SE417951B - PROCEDURE FOR THE MANUFACTURE OF FOODSTUFFS - Google Patents

Description

g 7113983-o 'J f ... depends on a good contact between the liquid and the solid. "net. Lower quality phosphate ore containing high levels of impurities is not suitable for use in the known methods of preparation of phosphoric acid and other phosphorus-containing fertilizers. Many off-pollutants The natural phosphate ore reacts with the sulfuric acid, which results in a very high sulfuric acid consumption. Because of the bad reaction kinetics in the production of phosphoric acid in a reaction medium systems containing two phases (liquid and solid) are required except for a maturation period as long as several days. In the production of non- granular phosphorus-containing fertilizer requires a long ripening time, up to several months, in order for the reaction to be complete and free sulfuric acid is reduced to a minimum. In the production of granulated phosphorus-containing fertilizer based on phosphate ore -important to achieve a good contact between the liquid and the solid .net to reduce various corrosive attacks of excess free acid brought to a minimum. In order to obtain hard fertilizers, granules, it is important that no unreacted sulfuric acid is present. gTriple superphosphate, which is highly concentrated phosphorus-containing fertilizers containing 44-46% PQO5, have been produced by decomposition phosphate ore using phosphoric acid. In this case, it is obtained citrate soluble phosphate using only precious phosphoric acid. It is an object of the present invention to overcome many of the disadvantages of the prior art methods of preparation in of phosphorus-containing fertilizers. Another object of the invention is * to provide a procedure for the production of fertilizers from relatively low quality phosphate ore. Another purpose is to provide a process for the production of manure oil, at which method uses the calcium present in natural lig phosphate ore. Another object is to provide a procedure for : production of fertilizers in the form of either solid, liquid or .suspension. Another object of the invention is to provide one faster reaction between untreated phosphate ore and sulfuric acid in a a mixture of gas, liquid and solid than has hitherto been been possible. Another object is to effect a reaction between pretreated, defluorinated phosphate ore and sulfuric acid. Further an object of the invention is to provide a method for producing position of fertilizer through the use of dilute sulfur-containing acid produced from sulfur oxides obtained from the combustion of sulfur natural fuels. Another object of the invention is to .x 7713983-0 kN provide a process for the production of fertilizers by use of the sulfur-containing acid needle as a by-product of sulfur generating processes, e.g. production of pulp by digestion of firewood. Another object is to provide a method for producing position of fertilizer in connection with a cheap source of sulfur oxide located in geographical proximity to fertilizer users. Another end- The object of the invention is to provide phosphorus-containing or other essential plant nutrients, which are easy to ammonium. Another purpose is to make ammoniated or unammonized, phosphorus-containing or others essential plant nutrients easy to granulate. Another purpose with The invention is to utilize sulfur oxides obtained in the combustion of sulfur-containing natural fuels in combination with phosphate ore and anhydrous ammonia for the production of fertilizers without any free ammonia is lost from the reaction system. Another end- The object of the invention is to provide a method for producing phosphorus-containing fertilizers, in which process sulfur dioxide converted to sulfuric acid, which effectively solubilizes the pretreatment lad, avfluogenated phosphate ore.

The invention thus relates to a process for preparation of fertilizer, and this process is characterized by a gas sulfur oxides are reacted with an aqueous solution having a pH of value of 3-8 in a multistage reactor to form evavelant acid, and that the pH of the solution of the sulfur-containing acid is maintained at 3-8 by means of a basic ion selected from calcium, ammonium and potassium ions, the calcium being derived from a phosphorus salt or a nitrogen-containing salt, to form a phosphorus-containing, a nitrogen-containing or a potassium-containing fertilizer part or a combination thereof, whereby the basic ion is made water soluble by reaction with the sulfur-containing acid at a pH value of 2.5-5 and the pH value of the solution is increased to a value between 3 and 8 to facilitate the reaction with the evavoxides.

The invention is described below in detail with reference to the accompanying drawing, in which Fig. 1 sohematically illustrates one embodiment of the method according to the invention for producing phosphate-containing fertilizers from ground phosphate ores; Fig. 2 is a schematic illustrates another embodiment of the method according to the invention for the production of phosphate-containing fertilizers from unpainted phosphate ore; and Fig. 3 sohematically illustrates an embodiment of the process according to the invention for the preparation of phosphate-containing fertilizers during recycling of liquid product§¿mm_ 7713983-o o h " Sulfur oxides are used in the process according to the invention formed during the combustion of sulfur halo.ga fossil fuels. such as carbon or oil, in an ordinary steam boiler or sulfur oxides formed as - products at various industrial plants, such as chemical plants, cellulose factories, refineries, fertilizer industries, steel mills I or gasworks. According to the preferred embodiments described below Sulfur oxides obtained from the combustion of coal were used, but it should be : it is seen that one can use sulfur oxides derived from any suitable sulfur oxide source. The method according to the invention makes it possible it is possible to use carbon with a high sulfur content, the preferred sulfur the content is higher than 2%. There are currently large amounts of carbon, which not utilized fi J¿5 due to the very high sulfur content, There is one increasing need for energy sources other than desulfurized oil or gas. Through satisfactory utilization of high sulfur coal and oil such needs are met very effectively, and existing combustion equipment after only minor modification. Very expensive methods of removing polluting sulfur oxides from smoke gases have not proved satisfactory. In accordance with According to the invention, it is possible to burn fuels with high sulfur contents, got which in many cases is more economical due to higher calorific value o and lower transportation costs. According to the invention, it is thus possible to burn fuels with a high sulfur content and utilize the resulting sulfur veloxides so that the exhaust fumes have low residual levels of sulfur oxides, lower than the permitted limits. It is therefore economically possible for power plants or other industries, which in steam nor burns sulfur-containing coal or sulfur-containing oil, to be utilized the process according to the invention for the production of fertilizers such as a by-product. vlo combustion possibly coal or oil with enough evevelhelt. Hvar- vld can but 'provide local growers with suitable goaeelmeeel so a de currently high transport costs are reduced. Some industries have been forced to switch to using coal to save oil 'ooh gas. By applying the method according to the invention it becomes in this case it is often possible to use locally occurring fuels, whereby high transport costs are avoided. The equipment required for implementation of the method according to the invention makes it possible both to remove SOX from flue gases ooh to produce fertilizers. This is very important; as the fertilizer industry is constantly trying to j. satisfy the increasing need for possible fertilizers. i i v Flue gases obtained in an ordinary coal-fired steam boiler containing this sulfur oxide and fly ash and with a temperature of 193-232 ° can be conducted by any conventional fly ash separating device and 7713983-0 s solids from the gas stream. Separator for separating fly ash may consist of a single stage of the type of rrwerogenic reactor, which below will be described in more detail. In such cases where it is It is advisable to mix the phosphate ore with the coal before combustion in the steam. boiler, it is not advisable to use any separator for separation fly ash.

According to an embodiment of the method according to the invention, which will be described in more detail below, the sulfur dioxide in the gas is converted to sulfuric acid, which was used to make preparations traded, defluorinated phosphate ore water soluble. If during the procedure according to the invention using untreated phosphate ore, it is desirable that the the sulfur dioxide in the flue gas and then hydrate the formed the sulfur trioxide so that sulphate ions are formed and the least possible amount sulfur dioxide is in equilibrium with the solution. By maximum oxidation of sulfur dioxide reduces the likelihood that sulfur dioxide will be released into the atmosphere. Solutions of sulfuric acid or of salts thereof, which contain the ion SO32 ", have a tendency to decompose below formation of SO2. It is therefore advantageous to oxidize the sulfur oxides as completely as possible during the formation of sulfates, which do not disintegrated. This oxidation can be carried out according to various methods, such as as by the use of an oxidation catalyst in direct contact with the flue gas, especially if the solids have been removed. The oxidation can also carried out in a separate absorption tower, in which a solution is passed in countercurrent to air. You can also carry out the oxidation in a downstream working heterogeneous absorption reactor of the type described in detail re below. The oxidation can be carried out in any absorption device, in which air is brought into contact with liquid obtained after ab- sorption of sulfur oxide gases. To the above solutions you can also add oxidizing salts so that sulfuric acid or sulfates are formed instead of sulfuric acid or sulfites.

The hot gas is led into a live contact unit cooler (absorption reactor), where some of the sulfur oxides are absorbed by direct contact between the gas and a coolant, which may be water or water containing pH-raising chemicals to improve absorption the sorption reaction. Upon cooling the gas, water evaporates, and it the solution obtained after evaporation is led to a sedimentation tank, from which the decanted liquid can be recycled to the cooler.

In the direct contact between the sulfur oxide-containing gas stream and the coolant cools the gas stream by evaporating part of the liquid phase.

This cooling during evaporation is driven about as far as the gas becomes saturated with water vapor, after which the gas stream is led to a reaction absorption tower, where the gas is brought into co-current contact or against ~ power contact with an absorbent liquid. 7713983-0 6 _ The function of the reaction absorption tower is that in solution transfer the sulfur oxides and possibly nitrogen oxides which are not solutions were used in the cooler. Solutions were used in the reaction-absorption tower with higher pH values. The gas liberated from acid anhydrides is passed then through a liquid trap and transported by means of a fan through a chimney into the atmosphere. In some establishments it may be appropriate to raise the temperature of the gas to a temperature before discharging above the saturation level. g e A chemical used to remove sulfur oxides is the calcium found in phosphate ores. Calcium is non-aqueous 'soluble in the form it is in the fi osphate ore and must therefore be made soluble by reaction with an acid. In the process according to the invention ~ one. can be to digest the phosphate malt and make the calcium ion 'water soluble I used sulfuric acid and sulfuric acid formed by sulfur oxides in flue gas in combination with phosphoric acid or miscellaneous phosphorus-containing acids or nitric acid or various nitrogenous acids to increase the acidic solubility. reactivity of the ion to the ore; i e i. if The chemical reaction between the acid and ground phosphate ore can be carried out in a suitable heterogeneous reactor; The phosphate ore can be used treated and unpainted form, and the reaction between the acid and phosphate the ore can be carried out in a ball mill. The function of the grinder is to promote the reaction by mechanically releasing any coatings of calcium salts on the phosphate ore. When a mixture of phosphorus-containing acids or Nitrogenic acids are used in combination with sulfuric acid and sulfuric acid. acidity, it may be appropriate to carry out mechanical grinding, when unground phosphate ore is introduced into the system. If the operation of the meadow boiler does not deteriorate and erosion does not constitute a disturbing factor, as in the use of stoker with underfiring or moving rust, you can sell the unpainted The phosphate ore with the acids in such a way that the untreated phosphate ore 'i§men is added to the coal burned in the meadow boiler; whereby one mal mal- but and the tile in the ball mill. The mixture of ore and clinker can also dry ground before insertion into the towers. The acidification can also take place by bringing pre-ground phosphate ore into contact with the acid mixture.

Powdered or ground_phosphatema1m can be introduced into rotating phosphoric acid in a cone for a reaction to take place prior to introduction into the reactant. the containers. Granulation is not desired; can the slurry from acidifying the cone is led to a flat »or Pemtransportör, where the slurry harden and the resulting product is pulverized to a ROP dukt. ("Run-Of-Pile"). Another option is to introduce the acidified the ore in a granulation system {If the oxide islands do not result in a sufficiently strong mixture of sulfuric acid and sulfuric acid, concentrated phosphoric acid must be added to these acids to increase the 7 7713983-0 7 untreated rate of phosphate ore. Possibly can nitric acid can also be used. The same consideration as regards the solution applies regardless of the way the slurry is treated. las. Another method of solubilization is to mix ground, untreated phosphate ore with an excess of air before introduction into the cooling tower.

Ground phosphate ore can also be introduced on top of the heterogeneous reaction. tower. The ore should be ground to at least such a particle size that 90% pass through a sieve with the opening 0.15 mm.

In the process according to the invention it is possible to use traded or by defluorization pretreated phosphate ore with so low BPL value as about 50. The BPL value is the phosphate content in phosphate ore expressed as tricalcium phosphate, Ca3 (PO4) 2. In the procedure according to invention, it is particularly convenient to use phosphate ore with BPL values of about 55-65. Phosphate ores with BPL values of 66 or less are considered be of low quality and are not suitable for use with those hitherto known processes for the production of fertilizers but are suitable to be used in the method according to the invention. The low price of low quality barrel ore makes the process according to the invention economical very attractive. Phosphate ores with BPL values higher than 66 are also suitable to be used in the method according to the invention.

When the calcium in the phosphate ore is made available with the help of sulfur oxides in the manner described above, the entire calcium requirement carried in this way, and there is no need to add precious calcium from other sources. That you do not need to buy calcium from any other source means a saving. If additional basic ions are required to remove the acidic ions formed during the hydration of the sulfur oxides, you can add ammonia or something cheap, alkaline to the system plant nutrient. If the economy allows, you can e.g. add potassium carbonate.

The slurry obtained by solubilizing the phosphate ore contains calcium ions, sulphate ions, sulphate ions, phosphate ions and optionally nitrate ions, other ions added with the desired acids, and ions released from the ore as a result of the solubilization. If nitrogen is desired in the final fertilizer product, is the cheapest the nitrogen source of anhydrous ammonia, which can be bound by the acidic slurry ningen. The anhydrous ammonia can be added to the slurry to neutralize it to a point where the acidity does not lead to or storage problem. Granules with too high a content of free acid have thus a tendency to be soft even after drying. If such granules clay is packed in bags, the excess acid causes an attack on the sacks ("bag root"). If granules with an excess of acid are handled Wïlolêå ”as_§êf ~ $ 9f {* _. P91kY? Š'É.¿_PïÉ? Ff1Éâ._låäö? Fêßa? On fšrêëöšššfïšââ_šït.ë after 'i those originally derived from plants, which were later petrified under g D; 7713983-0 8 drying, resulting in a baking of the granules. The advantageous economy with the neutralization step described above depends that the fixed nitrogen or the solid present nitrogen has a higher sales value than the original gaseous ammonia.

The formation of diammonium phosphate “also has an excellent buffering effect, i when using pretreated, defluorinated phosphate ore, and one obtains an excellent solution for keeping a low vapor pressure of SOÉ in weight with the solution. g g e D The ash retained in the slurry contains minerals, formation of carbon. These chemicals have a dual value. They are weak alkaline, as evidenced by the fact that in the past soap was produced by ' leach these chemicals out of the ashes and then saponify the fats thereby.

Most important, however, is this mineral, which contributed to the the growth of these prehistoric plants, can do the same for our crops. These minerals are commonly called micronutrients. They also give 7 gaaselmeaelspredukten an increased value; The most important ekenmleke contribution is that the fly ash from the steam boiler can be economically brought to the soil as part of the fertilizer. Otherwise it would [be necessary to remove fly ash and prevent environmental pollution, something that would be costly. e According to the invention, calcium derived from phosphorus is used. barrel ore for reaction with sulfur-containing acids, which are available to a very advantageous prle. It has previously been considered to solubilize phosphate ore with such a highly dilute sulfuric acid and sulfuric acid} obtained in conventional scrubbers. We have was appropriate to add concentrated phosphorus acid to the weak acids obtained from the sulfur oxides, since such a mixture increases temperature and improves the reaction with the ore so that the calcium ion becomes available. Use of weak sulfur-containing acids derived from flue gases for dilution of strong acids enables a greater position of phosphate-containing fertilizers than the use of only strong I _syror.

In prior art processes have concentrated¿ sulfuric acid I was added to phosphate ore for the production of ordinary superphosphate, The re- starving acidified product contains about 20% iP2O5 after ripening.

If concentrated phosphoric acid is mixed with phosphate ore in stoichiometric portions, after ripening a product containing 46% P2O5¿ is obtained According to a third commercial method, which is called process, phosphoric acid is prepared by reacting sulfuric acid with phosphoric acid. "_fatmalm_iwstökiometric proportions. sufficient e is used 7713983-0 9 sulfuric acid to precipitate all the calcium in the phosphate ore such as sulphate and other insoluble salts. The slurries are then transferred to a drum. filter, where the solids are separated from the liquid, which is called black phosphoric acid. In contrast, white or clear phosphoric acid is obtained, when one burns phosphorus and hydrates the resulting phosphorus pentoxide in water. In the preparation of the black phosphoric acid, the filtration becomes more and more troublesome, as the quality gets deteriorate. In the method according to the invention, the said cost is avoided. only the separation.

In the process according to the invention it is possible to use phosphate ore of lower quality than is possible with the known processes for the production of fertilizers. Low quality phosphate ore can be used small, because you do not need to separate sulfates (calcium) from it resulting acid, and since smaller amounts of phosphorus can be used acid or expensive concentrated sulfuric acid. In commercial production fertilizer in accordance with the present invention can be 25% of the phosphorus pentoxide in the fertilizer is derived from phosphoric acid and 75% is derived from the phosphate ore. Phosphate ore is used in the amount required to provide the required calcium to neutralize all the sulfur oxides in flue gases or other cheap sources of sulfur oxide. When the resulting the slurry is reacted with ammonia, it can therefore be freed the phosphate to bind the ammonia. The phosphoric acid used to help with the acidification becomes available for reaction with ammonia in the same way as when diammonium phosphate is produced. If, when using treatment of untreated phosphate ore carries out appropriate oxidation of sulfur dioxide it to sulfur trioxide and hydrates to form sulfates, can use a small amount of dilution water or sufficient re- circulating solution to increase the acid concentration 40%. In this case, very little phosphoric acid needs to be added to a ball mill. reactor. In this case, the ball mill was used as a reactor in connection with the solubilization, whereby the reaction can be carried out in a few minutes thanks whether the combination of mixing and grinding.

In the procedure illustrated in Fig. 1, untreated lad phosphate ore. In the illustrated process, the flue gas is first led through a single stage apparatus for removing dry particulate matter (fly ash). Use of this separator is optional. The one from the separator incoming flue gas is introduced into the cooling tower shown together with a ground phosphate ore fluidized with an excess of air. In the cooling tower ab- the sulfur oxides in the flue gas are sorbed by droplets obtained by ejection solution by spreading nozzle, and the acidified small droplets the pairs in turn react with the fine particles of phosphate ore. This Solubilization of the phosphate ore releases the calcium from the ore, thereby 7713983-0 10 h f 7 _ h obtains a phosphorus-containing slurry and calcium salts of the various veloxides. The cooling tower is cancerous with any effective heat _ogen reactor; as a single step of the heterogeneous reaction shown in Fig. 1 the actor, but without any separation plate. The slurry from the cooling tower led to a sedimentation tank. I I '* In a sedimentation tank 1, the solids are allowed to sink bottom; and the clear liquid is taken from the top of the tank and recirculated. cooled to the cooling tower so that calcium ions in the solution can react further with the sulfur oxides hydrated to acids. About the sulfur degree of oxidation is not sufficient to produce more than about 25% of the must be absorbed into the cooling tower, must be strong, commercially available phosphoric acid is introduced into sedimentation tank 1 to accelerate acidification. the making of the phosphate ore. h The gas emanating from the cooling tower, which is freed from the part of the sulfur oxides and is saturated with water vapor, is led to the ie gfig. 1 showed the heterogeneous reactor. This gas may also contain par- articles of ground ore which have not been agglomerated or reacted in refrigeration a tornet. In addition, further ground phosphate ore can be fluidized with air and mixed with this gas. The resulting mixture is introduced into the top of the heterogeneous reactor, and a solution is also introduced into the reactor. containing basic ions for the removal of residual sulfur oxides by reaction between the solution and the oxides. Any particles of ground phosphate ore, which has been carried from the cooling tower or introduced directly in the heterogeneous reactor, is further agglomerated and passed with it from reactor starting solution to a sedimentation tank 2. If concentrated the sulfur-containing acid is not sufficient for the desired one solubilization of the phosphate ore, strong, commercially available phosphoric acid also in sedimentation tank 2. According to the invention can starting from a gas stream containing low levels of sulfur oxides produce dilute sulfur-containing acids (concentration less than 60% by weight p_percent), something that has not previously been commercially possible. I sedi- Mention 2, the solids are allowed to sink to the bottom, and the clear the decanted liquid is recycled to the heterogeneous reactor. sight from svaveioxiaer, gas ygaska oçnffosphatmaimspartikiar the liberated gas is transported by means of a fan through a liquid trap as well further through a chimney into the atmosphere. A reheating device (not shown) may be required in some plants to increase gas temperature the trip to a temperature above the dew point. ' IN The pH of the heterogeneous reactor is regulated with the solution the calcium derived from the phosphate ore and can be further regulated 7713983-0 ll by adding anhydrous ammonia, potassium carbonate or something other economical, basic plant nutrients. A pH value of between 5 and 8 can be used depending on the degree of sulfur oxidation, the pH value 1 se- dimming tank 1, use extra acid, and the carbon sulfur content. In order to increase the absorption of sulfur oxides can also some of the solution from sedimentation tank 2 is returned to sedimentation tank 1 Via a valve V1 for increasing the pH value in sedimentation tank 1 or vice versa. If the higher pH value is maintained in sedimentation tank 2, a pH value of between 2.5 and 5 can be maintained in the sedimentation tank 1, also here depending on the degree of sulfur oxidation, the pH in sedimentation tank 2, use extra acid and carbon sulfur content. During certain conditions with regard to the sulfur content of the carbon, acceptable SO losses, degree of sulfur oxidation or pretreatment and defluorization of the phosphate ore, as well as used extra acid, the pH value can be kept the same level in both tanks, which facilitates the operation and selection of materials. In order to be able to regulate the pH values and the reaction of the phosphate ore, the sedimentation tanks 1 and 2 are interconnected with each other_in such a way that solids or liquids can be transferred between thoughts. When pretreated, defluorinated phosphate ore was used in combination with oxidation of SO2 to SO3 can solution with higher pH from sedimentation tank 2 is introduced into sedimentation tank 1 for regulation of the pH of the solution injected into the cooling tower. When pre-treated. defluorinated phosphate ore was used to absorb the sulfur oxides in it state they exist in the flue gas, sedimentation tank Q can be divided to form an additional reaction vessel, wherein ammonia is added for regulating the pH in the heterogeneous reaction and in the cooling the tower.

From the bottom of both sedimentation tank 1 and sedimentation tank 2, a slurry of solid and liquid is taken out, and this slurry is passed to a pre-neutralization container and / or to a granulator depending on the solids content of the slurry. Ju mera the more liquid the slurry contains, the more slurry is led to the neutralization container. The distribution between pre-neutralization conditions the holder and the granulator are regulated by means of a valve V2. If further solubilization of the ore is desired, one can in the pre-neutralization vessel introduce strong phosphoric acid and possibly strong nitric acid, as shown in Fig. 1, to promote further solubilization and evaporation.

Continued solubilization takes place in the granulator and may possibly end up in the dryer. If additional anhydrous ammonia is added in the pre-neutralization vessel together with phosphoric acid, the to 77713983-0 o a 12 heat to effect a decoction of liquid. About the slurry from the sedimentation tanks contains a high content of solids, can the slurry is led directly to the granulator, where the reaction between Free ammonia and acids take place without the need for additional evaporation.

If it is desired to produce complete fertilizer (NPK fertilizer), add potassium carbonate in desired amounts in the granulator. As with normal fertilizer application, the material is passed from the granulator via a drying appliance and a radiator to a screen, and those separated therein, too large? the particles are ground and mixed with the separated, too small particles poch is recycled to the granulator. If the liquid content is small, it is reduced the amount of recycled material is reduced, and grinding of the screened the product does not have to be necessary. * d that in the process according to the invention it can be prepared 'liquid fertilizer, wherein a part of the recirculating liquid is discharged, is taken out of the system through a control valve V3, as shown in Fig. 1.

For this liquid product, you can in a container provided with Omnöpare å (ioke shown) put potassium carbonate, uncoated ammonium nitrate or something other water-soluble plant nutrient so that the product has the desired a fsättning. When pretreated, defluorinated phosphate ore is used, allow at the high reactivity that the main part of the liquid flow is taken out as liquid fertilizer, if desired. This would eliminate the need for ~ pre-neutralization container and granulation plant with associated the equipment, whereby both the capital costs and the operating costs reduction. å å 'å By suitable control of the valve V6, one can as a pro- product drain a fertilizer suspension. In a stirrer equipped with holder (not shown), this nutrient can be added to this suspension ß substances and agents for stabilizing the suspension, Part of it very fine silicon-containing material from the fly ash and the solubilized ore has a stabilizing effect on this suspension. As shown of Fig. 1, in the process according to the invention, liquid fertilizer, fertilizer suspension or solid fertilizer depending on the end product desired. o p The heterogeneous used in the process according to the invention the reactor can be any suitable apparatus which charges rapidly. chemical reaction between the reactants in a heterogeneous mixture of gas, liquid and / or solid, such as one fitted with filler bodies reactor or any other reactor designed to avoid clogging setting. A particularly suitable device is described in detail in Swedish patent application 77 13 982-2- 7713983-0 13 The heterogeneous reactor shown in Fig. 1 has an exterior housing 10, the cross section of which is preferably circular but may also be square, rectangular, triangular, hexagonal or have any other symmetrical polygonal shape. The cross-section of the housing may also have another geo- metric shape, which is symmetrical with respect to the axis of the apparatus, at the main condition is that the casing is gas and liquid tight and enables regulated gas flow through the reactor. To enable maximum flexibility capacity when using the reactor, the housing 10 can be manufactured in sec. sections, each section being provided with flanges, such as 11 and 13, for rigid coupling with adjacent sections provided with similar flanges, such as 12 and lt. Instead of flanges, it is possible to use turn over any suitable coupling means. To make it easier installation of large units, the sections can be welded before transport and assembly. Fig. 1 shows a heterogeneous two-stage reactor.

The heterogeneous reactor is arranged with the shaft vertical and with an inlet opening for solid, liquid and gas in the upper parts. The inlet opening can be arranged vertically or horizontally.

The gas is introduced into the reactor through the inlet port at a sufficient speed. heat and sufficient pressure to transport the gas through the reactor. In- the running pressure is lower than the atmospheric pressure in most cases so that it use the fan is not affected by abrasion of any solids in the incoming gas or by chemical attack of corrosive components.

The device is a low pressure device, and the gas velocity inside the housing is usually between 60 and 560 m / min before the inflow into the nozzle 21.

A spreader 41 may be located in the center of the apparatus inlet, and through this diffuser a solid or liquid reaction is introduced. component, an adsorbent, an absorbent or a refrigerants in the form of droplets, preferably with a diameter of between 40 and 1500 / um. Larger drops may be desirable to compensate for evaporation when evaporation conditions exist. The spreader 41 is preferably in the form of a solid cone, which alone or in combination tion with several similar bodies arranged in a certain pattern allows introduction of small water droplets over the entire cross section of the gas stream, before the gas flows into the conical nozzle 21. It is desirable to different size liquid droplets to achieve maximum differential accelerations, decelerations and speeds through the apparatus, whereby the reaction rate is increased. The injection pattern should extend over the entire area of the inlet 25 of the nozzle 21, and any suitable one spreader pattern is satisfactory. The spreader 41 can also be used 1713932-0 14 for introducing solid particles of the above size into mouth ~ paragraph 21 inlet 25. V dj g l The heterogeneous reaction mixture of gas, liquid and solid is introduced into the converging nozzle E1 through its inlet 25. The inlet 25 is preferably round and the nozzle 21 is preferred conical, but also other geometric shapes symmetrical in relation to those to the axis of the apparatus are useful. The cone ratio, i.e., the ratio the active inlet area between the cone and its active outlet area, should be between 2 and 64, preferably between 2 and 36. With effective area refers to the area perpendicular to the gas flow axis. IN The length of the converging part of the nozzle 21 is determined by convergence angle Å (see Fig. 1) teh the cone ratio defined above the. The mean convergence angle is suitably between 6 and 20 ° and is preferably between 10 and 16 °. By mean convergence angle is meant the angle between a straight line drawn from the inlet to the outlet and a vertical line (see angle A in Fig. 1). The sides of the nozzle 21 need not be straight but may be slightly convex or concave; The distance between the nozzle outlet 24 and the separation surface c 31 should be about 1.3-2.5 times and preferably 1.6-2.0 times the diameter of the outlet 24. l p Fig. 1 shows the separation surface 31 as a stop plate 31, E A l g g g c "Which is of sufficient size to allow substantially all particulate matter 'material from the nozzle outlet 24 should strike the plate at the same time as the area between the plate and the apparatus housing 10 is sufficient for the gas to be able to flow around the plate without significant pressure drop. Although the stop plate 31 in Fig. 1 is shown as a flat plate, one can also use a weak con- _kav plate to facilitate the passage of the gas around the edges and facilitate the removal of particulate matter. For reactions that do not sting separation of solid and liquid phases from the gas phase or for mass transfer Processing processes, such as evaporation in a cooling tower, do not require separation surface in the gas stream after the nozzle outlet. c g Additional spreaders may conveniently be located above the separation plate 31 in such a way that, with their aid, one coils 'removes particulate matter from the sheet B1, so that this material transported further through the device and out through the bottom outlet. Several such diffusers may be arranged around the periphery of the plate B1, or a single spreader can be: located in a central location. When enough fluid is used, the separation surface will become liquid and the pair the article material will not hit or adhere to the plate 51 without being trapped by the fluid. It is important that the fluid jets that 7713983-0 15 hits the plate 31 have such a direction and force that they pour the plate 31 relatively free of particulate matter. The reactor can also vase without the extra diffusers for cleaning the separation surface.

Fig. 1 shows an apparatus with two series-connected stages arranged above each other. From 1 to about 6 series-connected nozzle steps are suitable in the heterogeneous reactors used according to the invention. Before- typically 2-4 series connected steps were used. The number of nozzle steps is matched by the ability of the reactants to react with each other, and a large number of steps may be required when using special difficult materials. The number of steps is also affected by the conversion of the nozzles. gene angles and cone ratios.

Below the separation plate 33 in the lower stage contains the apparatus of Fig. 1 a container 15 for removing liquid and slamming. Furthermore, there is an outlet for clean gas in the form of a line 16 below or adjacent to the separation plate 35, as shown in Fig. 1. Either inside or outside the appliance, it may be appropriate to release the the only gas from the remaining liquid by means of a liquid trap 17, which removes fine liquid droplets remaining in the gas together with any solid or gases trapped by such droplets. The device shown in FIG. The vertical arrangement of the converging nozzles shown in FIG. particularly advantageous. In such a device equipped with a liquid trap and with a cone ratio of 4 and a convergence angle of 12 ° is namely pressure drop 89 mm H20 when using a nozzle, l45 mm H20 at use of two series-connected nozzles, 178 mm H2O during use of three series-connected nozzles and 211 mm H2O when using four series-connected nozzles, if the inlet speed is approx. 630 m / min. When the same apparatus equipped with two series-connected nozzles was used for removal of SOX and production of fertilizers in accordance with present invention, a pressure drop of 20 mm H 2 O was obtained and excellent process results, when the inlet speed was about 120 m / min. At vertical serial connection of two or more nozzles thus becomes the pressure drop less than the cumulative value.

The second stage of the heterogeneous reactor shown in Fig. 1 is identical to the first step. However, one can individually clay the amount of water or liquid chemical introduced into resp. step in front of the conical nozzle inlet and the amount of liquid that sprayed on the separator plates in resp. step. In addition to the added volumes the liquids used can also be different in the different steps. 7713983-o 16 o y When liquid, solid and gaseous components in mixture is passed through such nozzles as 21 in Fig. 1, a intimate contact between the reactants, resulting in the desired the high reaction rates. It is assumed that the high reaction achieved option efficiency depends on the differential speeds, acceleration and decelerations obtained when the compressible gas is contained holding non-compressible substances are passed through the conical nozzles, now whereby a relatively large expansion takes place after the outflow from the mouth. The systyox outlet 24. In the flowing reaction mixture there is a large play distribution of compressible and non-compressible substances. If external more solid or liquid particles are introduced into the gas stream, the content increases non-compressible components of the mixture. Through the spreader 41 can to introduce liquid or solid particles with many different particles sizes, and together with liquid or solid particles with many different particle sizes in the incoming gas stream are provided extremely high collision speeds and high speeds of compressible gas past the non-compressible particles or droplets, which starves in highly efficient reactions.g 2 To reduce the height of the heterogeneous one shown in Fig. 1 the reactor, multi-cone nozzles can be applied in each step.

Another preferred embodiment of the invention illustrates In Fig. 2. According to this embodiment, untreated, unpainted phosphor is used. fatmalm. This is possible by using the ball 2 shown in Fig. 2 the mill, in which unground phosphate ore is introduced and which acts as a combined grinder and reactor. According to this embodiment, Mman even if desired, use dry, ground phosphate ore. If desired¿ can of SO 2 to SO 3 instead of as illustrated in Fig. 1 the ground phosphate ore is introduced into the heterogeneous reactor, as shown in Fig. 2. The flue gas flow in Fig. 2 is the same as in Fig. 1. the fluids in the liquid streams are due to the desire to maximize the acidification reaction in the coal mill. For this reason, it is appropriate that in the tower keep such a low pH value that is compatible with the desired absorption of sulfur oxides. This is accomplished by maximizing oxidation the process increase the pH value by adding NH3 and / or KZCOB.

If the pH is set at 2.5-3.5 and a high sulfur content is achieved oxidation, a high concentration of sulfuric acid is obtained, whereby the need of phosphoric acid decreases. The higher the degree of oxidation that is achieved, the higher the sulfuric acid concentration, which increases the solubilization ratio mágan i kulkvarnen. A high degree of oxidation can be achieved by using of a catalyst in the gas stream or by aeration of the liquid 7713983-0 17 which is introduced into the heterogeneous reactor or by absorption of oxygen in the heterogeneous reactor or in the cooling tower. If monocalcium dihydrogen ortho- phosphate and / or monoammonium hydrogen sulphate are added to the solution for pH, more sulfur oxide hydrate can be absorbed in the cooling tower, from which the outgoing liquid is led to the ball mill for acidification of the unpainted phosphate ore. The lower the concentrations of sulfates and sulfites, especially sulfates, are in the recycling liquid, deso larger amounts of concentrated phosphoric acid need to be mixed with the the tower formed the acidic solution. By mixing the different acids can thus regulating acid activity and acid strength. so that solubilization the reaction in the ball mill takes place as quickly and as completely as possible ligt. The more dependent the process becomes on the acid derived from the sulfur the oxides, the more important the grinding effect in the ball mill so that primarily releases the coatings of calcium sulphate and calcium sulphite which tends to reduce both the reaction rate and the reaction degree of tion. The slurry of solid and liquid from the ball mill can passed through a filter; and the solids separated on the filter can led directly to a plate or belt conveyor, whose rotating knives or other pulverizing agents provide a ROP product with a composition between ordinary superphosphate and triple superphosphate. It matters led to the conveyor may also come from the bottom of the gene reactor. The slurry of solid and liquid from the ball mill led according to Fig. 2 to a separation system (a filter), from which a high solids slurry is led to a pre-neutralization transfer container and from there on to a granulator, a dryer, cooler and a sieve “for the production of solid fertilizer product.

The slurry from the ball mill can also be led to a spare tank, such as is shown by the dashed line in Fig. 2, if an outage occurs.

The filtered solution can be recycled to the heterogeneous reactor. as shown in Fig. 2.

From the cooling tower, a gas saturated with moisture and content is passed. holding sulfur oxides which have not been absorbed in the cooling tower, and this mixture is introduced into the heterogeneous reactor, where the calcium solution sorbs the sulfur oxides in the gas to form a slurry, which led to a sedimentation tank 2. The from this sedimentation tank tank decanted liquid can be recycled to the heterogeneous reactor via an additional aeration device, as shown in Fig. 2, to increase the efficiency of sulfur oxide removal. It may also be appropriate? guiding the decanted liquid through a clarification device for external more solid removal so that the diffusers in the heterogenw the reactor becomes clogged. 7713983-0 18 Alternatively, it may come from the heterogeneous reactor the slurry is passed through a filter for purifying the liquid so that the the particles in the heterogeneous reactor are not clogged, leaving them on the filter separated solids can be led to the said plate or belt conveyor the porter. If the plant also includes a conventional granulation facility, the slurries from the boiler clearing device, residence the tank and the sedimentation tanks are led to pre-neutralization tanks. or to the granulator or to both, depending on the concentration the use of solids, Use of a conventional granulation laying also makes it possible to introduce anhydrous ammonia into it in Fig. 2 shows the treatment tank from which the slurry is led sedimentation tank 5. The liquid decanted from sedimentation tank 3 guided through the clarification device or any other device for removing solids, so that clogging of the diffusers in the heterogeneous a reactor is prevented. This allows for further pH control in it heterogeneous reactor. The one obtained from the bottom of the sedimentation tank 5 the slurry is combined with the other slurries immediately to the neutralization container or combined with the liquid from the clarification the device. wherein the latter liquid stream is regulated by a valve V16. The slurries that lead to pre-neutralization containers 'clean or to the granulator or to both are treated in the same way which has been described for the process illustrated in Fig. 1, so that a solid, granulated fertilizer product is obtained. D D i then D Liquid fertilizer product can be removed from the recirculation the current to the diffuser of the heterogeneous reactor, the draining of such liquid fertilizer is regulated by means of a valve V12 in the line between the clarifier and the heterogeneous reactor. Donna flytnndw fertilizer product is passed to a stirred tank (no reprimanded); where potassium carbonate, uncoated ammonium nitrate and other common ingredients in liquid fertilizers, so that a product with the desired composition is obtained. 1 the liquid from the clarifier can also be passed through valve V16 and joins the slurry flow below the valve V. The resulting mixture is led to a valve V17, using 15 from which it can be bottled as a fertilizer suspension. According to According to the invention, fertilizers can thus be prepared, wherein a gas containing containing sulfur oxides is reacted with water in a multi-stage reactor to formation of sulfur-containing acid, after which the sulfur-containing acid is reacted test with a basic ion selected from calcium, ammonium and potassium ions, wherein the potassium is derived from a phosphorus-containing or nitrogen-containing salt, 7713983-0 19 to form a phosphorus-containing, nitrogen-containing or potassium-containing fertilizers or a combination thereof. The calcium ion is mainly desvis from phosphate ore.

The flow of gaseous, liquid and solid substances through the heterogeneous reactor, the cooling tower and the other contactors used The reactions can take place in countercurrent or in cocurrent or in any combination hence. The gas can thus flow inward current with both the liquid and that solid, or in cocurrent with one substance and in countercurrent to it other substance, or in countercurrent to both the liquid and the solid.

When untreated phosphate ore was used in the process of invention, it has been found that the sulfur-containing acid to the majority (more than 50%) must consist of sulfuric acid in order to obtain satisfactory conversion of the phosphate ore and satisfactory removal of sulfur dioxide from the flue gas. To obtain predominantly sulfuric acid, it is necessary to oxidize the sulfur oxides in the flue gas. This becomes more difficult with increasing sulfur content in the spent fuel. let. Under such conditions, it has been found appropriate to bilise the phosphate ore with a solution with a pH of about 2.5 ~ 4.0 and increasing the pH of the solution to about 5-8, preferably 5-7, for to facilitate the removal of sulfur oxides from the gas stream.

When pretreated, defluorinated phosphate ore is used in pre-treatment process according to the invention, the sulfur-containing acid may be sulfuric acidity. Satisfactory conversion of the phosphate template is obtained. but and satisfactory removal of sulfur dioxide from a flue gas obtained by the combustion of high sulfur fuels. Such treated, defluorinated phosphate ore has been shown to react very well with a sulfur-containing acid consisting mainly of sulfuric acid. The Thus, it becomes necessary to oxidize the sulfur dioxide in order to shall obtain a satisfactory solubilization of the phosphate ore.

Under such conditions, it has proved appropriate to solubilize phosphate ore with a solution having a pH of about 5-5, preferably 3.5-4.5, and to increase the pH of the solution to about 5-7, preferably 6-7, to facilitate the removal of sulfur oxides from the gas stream. but.

By pretreated, defluorinated phosphate ore is meant mainly crude tricalcium phosphate produced by thermal defluorization of fluorapatite. Processes for the production of defluorinated phosphate ore described in "Rhosphoros and Its Compounds", Volume II, John R. Vanwazer. lnterscience Publishers, Inc., New York, N.Y. l96l, pp. 1090-1092. One another suitable form of pretreated phosphate ore, which is particularly suitable .ivvizàaz-o 20 when using a main source of electrical energy, is calcium metaphosphate produced by simultaneous oxidation of elemental phosphorus and turnover of the resulting phosphorus pentoxide with phosphate ore; see pages 1095- 1097 in the above work Phosphorus and Its Compounds. In the event of method of the invention useful pre-treated, defluorinated phosphorus barrel ore usually contains less than about 0.2% F ooh. at least about 18% P (gull P2o5). untreated fluerepetlt contains ee 3, 5 v; F. Avfluerez-ed phosphate ore is now commercially available.

When using pretreated, defluorinated phosphate ore For example, the process according to the invention can be carried out at higher pH values than when using any untreated feefehmelm. The pH value is an important factor both in the removal of sulfur dioxide and in the conversion of phosphate ore. The pretreated, defluorinated phosphate ores have been shown to be distant over 90% of the sulfur oxides, mainly SO2, in the cooling tower during formation of mainly sulfuric acid. A pH value of between 3-5 is suitable in the cooling tower and in the sedimentation tank wedge, the preferred pH value being it is between 3.5 and 4.5. The conversion of pretreated, defluorinated phosphate ore to an ammoniorable fertilizer by solubilization with sulfuric acidity is greater than 90%. It has also proved appropriate to pretreat the defluorinated phosphate ore by leaching in water. For- treatment by leaching for a few days has been shown to increase sharply ore solubilization. Longer times, of the order of 30-120 days, are appropriate. The extremely effective removal of sulfur dioxide from a flue gas obtained during the combustion of a fuel with a high sulfur content improves at a pH in the heterogeneous reactor of between 5 and 8, preferably between 5.5 and 6.5. 'i'i Fig. 5 illustrates an embodiment of the method according to the invention, where a part of the product is recycled to it heterogeneous reactor (tower 2) and injected in liquid form therein. This embodiment has been found to be particularly suitable when using phosphate ore, whereby the sulfur oxides can be removed very efficiently from the gas stream without oxidation. The sulfur-containing acid formed, mainly sulfuric acid, has been shown to solubilize the treated the phosphate ore satisfactorily. As shown in Fig. 3, sulfur-containing carbon is fed through a feed means into a meadow boiler 51, where the coal is burned. The flue gases leave the boiler through one flue gas duct 62. In the horizontal duct 62 there are diffusers 90 for cooling of the hot flue gas before it is introduced into the cooling tower (tower 1).

It has been found appropriate to cool the flue gas to 54-71 ° C before the flue gas. the gas is introduced into tower 1. The cooling tower 52 (tower 1) is a heterogeneous reactor 7713983-0 21 which provides a good contact between liquid and gas. In tower l there are spreading re 91, 92 and 95. To all these diffusers and to the diffuser 90 in the channel 62, solution is led from the container 77 for liquid from tower 2.

The solution is pumped from the container 77 by means of a pump P-10 through a conductor 79, and the amount of liquid to the diffusers and to the container 70 for liquid from tower 1 is regulated by means of a valve V32. The gas from tower l led through a conduit 55 to the top of tower 2. Tower 2 may be which any suitable heterogeneous reactor to provide efficient reactivity. tion between liquids and gases. A particularly suitable heterogeneous reactor is a reactor of the type shown in more detail in Fig. 1. The gas stream led down in tower 2 and brought into contact with liquid sprayed through the diffuser 94 and 95. The gas leaves tower 2 through a channel 55, which is provided with suitable analysis means, such as an IR analyzer 56 for determining of the content S00 and a dust meter 58. In the channel 55 there is also a liquid trap 57 for lowering the temperature of water vapor in the outgoing smoke gases. By means of a fan 59, the gas is led through a chimney 60 into the atmosphere. the fern. This fan can also provide the required draft through the steam boiler.

Liquid is led to the container 70 from the bottom of tower 1 through a conduit 81 and in addition liquid from the container 77 through a line 78 containing a control valve V51. The liquid from the container 70 is passed to a reaction vessel 72 through a line 71, optionally by means of a pump P-ll. The reactant components for the production of fertilizers, in addition to the sulfur-containing acids formed, are introduced into the systemof by adding to the reaction vessel 72. These reaction components are water, ammonia and phosphate ore. Solubilization of the phosphate ore o takes place in the reaction vessel 72, and the pro- formed in the vessel 72 the product is passed through a line 73 containing a control valve V-O to a sedimentation tank 74, from which liquid fertilizer product is taken out through a line 75.

Liquid product from tank 74 is also recycled to the diffusers 94 and 95 in tower 2. The liquid leaves tower 2 through a conduit 82 and is led to the container 77. Liquid from the container 77 is partly passed to the diffusers in tower 1 and partly directly to the container 70.

When operating a test facility containing such equipment shown in Figures 1 and 5 has obtained a total pressure case of approx. 50 mm H2O between the gas inlet to the cooling tower and the gas outlet from the heterogeneous reactor. This means a big energy saving in comparison with conventional scrubbing drills, in which the pressure drop is 1000- l750 mm H20. s_? v139as-o 22 The carbon residue obtained during combustion can be ground and added to the fertilizer product produced, whereby waste problems are eliminated. Such a fertilizer has been used in cultivation dept soybeans, licorice (Bronbus) and spring wheat. In all cases, the plants grew considerably faster and became considerably larger than comparison plants at cultivation in good topsoil. d 'go The invention is illustrated by the following, non-limiting d exampler “I W e o l Example 1 o Liquid fertilizers were prepared on the basis of untreated load phosphate ore using equipment similar to that shown in Fig. 1, but without pre-neutralization container and granulator and associated apparatus for the production of solid fertilizers. Coal content containing about 3.37% sulfur was burned in a steam boiler, and the flue gas from the boiler containing 8.8% CO 2 was led without separation of fly ash * into the bottom of the cooling tower together with an excess of air (S9, lš) to facilitate the oxidation that can be achieved. The gas flow rate density was 7.9 m3 per minute at 16 ° C. Untreated phosphate ore was used with such a particle size that 82% passed through a sieve with the opening _0.062 mm and mainly 100% passed through a sieve with an opening of 0.84 mm; This phosphate ore was added to sedimentation tank 1 in an amount of 36.8 kg in a time of 5.5 hours. The liquid in sedimentation tank l and was recycled to the diffusers in the cooling tower in an amount of 2.6 l / m 5 p gas, with clogging of the nozzles being prevented at 1/5 of the calculated the flow rate. The pH of the liquid fed into the cooling tower was 4.2, and the pH of the liquid passed from the cooling tower to sedimentation tank 1 was 3.5. The gas was removed from the top of the cooling chamber. tower and was introduced on top of the heterogeneous reactor.

The sediment ring tank 2 was divided into a tank for receiving liquid from the heterogeneous reactor and one with this tank bound ammonia reactor for treating the solution to the heterocycle gene reactor. , d Water and ammonia were added to the ammonia reactor and the mixed liquid from this reactor was recycled to the diffusers in the heterogeneous reactor in an amount of 3.1 l / m9 gas, here too clogging of the diffusers was prevented during operation with reduced flow.a The liquid fed to the heterogeneous reactor had a pH of 6.3, and the liquid passed from the heterogeneous reactor to the the capture tank had a pH of 5.9. 7713983-0 25 The total removal of SOÛ from the flue gas was 347.

Liquid fertilizer product removed from the receiving ningstanken. The active components of the fertilizer were nitrogen from mmmwmomfwmt fi àfæmm fl mm Example 2.

A plant as shown in Fig. 1 was used, which however, was modified by both sedimentation tank 1 and sediment ~ tank 2 were replaced by a number of series-connected devices, namely a receiving tank, a solid flow reactor, a mixing reactor ~ and a sedimentation tank. Carbon containing 3.4% by weight of sulfur was burned in a steam boiler, and the flue gas from the steam boiler was led to ten of the cooling tower. eProtreated, defluorinated phosphate ore with a fluorine content of less than 0.18% was hydrolyzed in water for 11 days before introduction in the system. The hydrolyzed, pretreated, defluorinated phosphate ore (100% passes through a sieve with an opening of 2.33 mm) was inserted into the solid the flow reactors. It turned out that the pretreated, fluorescent The phosphate ore was reactive enough to obtain desired removal of SO 2 and desired conversion of the ore with the acids formed by the sulfur oxides in the flue gas. The desired conversion was obtained both with coarse particles (100% passes through a sieve with the opening 2.38 mm and 2 '% pass through a sieve with the opening 3.59 mm) and with fine articles (100% pass through a sieve with the aperture 2.38 mm and 75% pass through a sieve with the opening 0.074 mm). The liquid in sedimentation tanks were mixed and recycled to each of the towers, whereby the calcium phosphate concentrations were sufficient for the sulfur oxides in the flue gas would be absorbed. When the liquid from the heterogeneous reactor had a pH of 6.55, a sulfur dioxide removal of 90.1% was maintained and a sulfur dioxide concentration in the outgoing gas of 142 ppm. When work was carried out on the second of 5.70 a sulfur dioxide removal was obtained of 85.6% and a sulfur dioxide concentration in the exhaust gas of 207 ppm.

When ammonia was added to increase the pH of it from the heterogeneous reactor coming liquid to a pH of between 6.4 and 6.9, the sulfur dioxide removal increased to over 92%, which corresponded to a sulfur dioxide concentration in the outgoing gas of 110a ppm.

In all the cases described above, water was added to the reaction. to compensate for the dot water that evaporated in the dry Yl G11. _ 7713983-ng 24 In Exemnel §.

Such a plant as shown in Fig. 3 was used for .setting of liquid fertilizers based on pre-treated. avfluore- rad phosphate ore. Carbon containing about 6.2% by weight of sulfur, calculated on the dry weight was fed by means of a stoker with underheating in a double _ sided steam boiler and burned with an excess of air. The flue gases led from the boiler to the bottom of tower 2. In other comparable experiments 2 used as little as a 20% excess of air. By water injection In the duct between the boiler and tower 1, the temperature of the flue gas was lowered to -66 °, before the flue gas was introduced into tower 1. 59 kg of fluorinated phosphate ore containing less than 0.18 F was hydrolyzed in 1.7 months of water below 2 weeks. Water only and pretreated, defluorinated phosphate ore was placed in the reaction vessel to obtain the desired chemical conditions. conditions for the removal of sulfur oxides and the production of fertilizers.

When the recirculating liquid introduced into tower 2 had a pH value of 6.90 and the liquid carried from tower 2 to the liquid container from tower 2 had a pH of 6.50 a sulfur dioxide removal was obtained those from the flue gas of 92.5%. 2 When in addition to water and defluorized phosphate ore also Winfried a small amount of ammonia in the reaction vessel, increased removal of sulfur oxides, as shown in the table below, and conversion The phosphate ore and ammonia content was 90%, calculated using of the amounts of reaction products formed, i.e. calcium sulfite, calcium sulfate and ammonium phosphate. The values given in the table below are determined at 15-minute intervals. The flue gas left tower 2 with one -speed of 12.9 me / min and with a temperature of 4300. 7713983-0 25 Tower 2 Sulfur pH in pH ut ppm i utgàen- Prooentuellt the gas removal 6.60 6.0 6125 '94 .73 6.55 6.0 123 94.81 6.50 6.0 111 95.32 . 6.50 6.0 109 95.40 6.55 6.05 96 95.95 6.50 6.0 103 95.7 6.5 6.0 130 94.5 6.4 6.0 111 95.3 6.4 5.0 116 95 1 6.43 5.9 136 94 3 6.45 5.95 96 96 6.45 6.0 90 96.2 6.45 6.0 83 96.5 6.45 6.0 79 96.7 6.45 6.0 103 95.7 6.43 6.0 87 '96.3 6.46 6.0 88 96.3 6.42 6.0 85 96.4 6.42 6.0 101 95.7 6.35 5.78 95 96.0 6.3 5.88 119 95.0 According to the US limit values, a sulfur dioxide content in outgoing flue gases of 177 ppm, which in this case mctsva ~ 99.5% removal of the total sulfur content. By working in accordance with the present invention, one can thus exceed this limit value, when burning coal containing 6.2% sulfur.

It is obvious that many different variations of the above described preferred embodiments of the method according to the invention are possible within the scope of the invention.

Claims (1)

7713983-o l26 ¶¶ P a t e n t k r a v al; Process for the preparation of fertilizers, characterized in that a gas containing sulfur oxides is reacted with an aqueous solution having a pH value of 3-8 in a multi-stage reactor to form sulfuric acid, and the pH value 1 the solution e of the sulfur-containing acid is needled at 3-8 by means of a baeic ion selected from calcium, ammonium and potassium ions, the calcium potassium-containing fertilizers or a combination thereof, the basic ion being made water-soluble by reaction with the sulfur; containing the acid at a pH of 2.5-5 and the pH of the solution is increased to a range between 3 and 8 to facilitate reaction with the sulfur oxides. Z e 2, ¶ Process according to claim 1, characterized in that the sulfur-containing acid consists mainly of sulfuric acid, that the calcium ion is made water-soluble at a pH value of 2.5-4.0, and that the pH> of the solution is increased to a value between 5 and 8 to facilitate the reaction with the sulfur oxides. A method according to claim 2; It is known that the calcium ion is made water-soluble at a pH value of 5-4, and that the pH value of the solution is increased to a value between 5 and 7 to facilitate the reaction with the sulfur oxides. A method according to claim 2, claiming to be cold? The cium is derived from phosphate ore which is pretreated by leaching into the heat. 5. A process according to claim 2, characterized in that the sulfur oxide-containing gas is obtained during the combustion of fossil fuel. ï n n _ l t l 6. A process according to claim 2, characterized in that the sulfur oxide-containing gas is obtained from sulfur-producing chemical reactions. 7. A process according to claim 2, characterized in that the calcium is derived from phosphate ore with an equivalent Ca 3 (PO 4) 2 - content of 55-65%. ¶ ¶ e l8. Process according to claim 1, characterized in that of water the sulfur-containing acid consists mainly of sulfuric acidity, that the calcium ion originates from defluorinated phosphate ore and is made water-soluble at a pH value of 3-5, and that the pH the value is increased to a value of 5-8 to facilitate the reaction with the sulfur oxides. 9. A process according to claim 8, characterized in that the calcium ion is made water-soluble at a pH value of 3.5-4.5 and that the pH value of the solution is increased to a value of 6-7 to facilitate the reaction with the sulfur oxides. 10. A method according to claim 8, characterized in that the fluorinated phosphate ore contains less than 0.2% by weight of fluorine. 11. A method according to claim 8, characterized in that the defluorinated phosphate ore is pretreated by leaching in water. 12. A method according to claim 8, characterized in that the sulfur oxide-containing gas is obtained during the combustion of fossil fuel. 13. A process according to claim 8, characterized in that the sulfur oxide-containing gas is obtained from sulfur-producing chemical reactions. Process according to Claim 8, characterized in that the calcium is derived from phosphate ore with an equivalent Ca 3 (PO 4) 2 -haiu of 55-65 f. ), 1,591,272 (71-38), 3,697,248 (71-38)