CN112520786B - Acid-soluble titanium-rich material and preparation method and application thereof - Google Patents

Abstract

The invention discloses an acid-soluble titanium-rich material and a preparation method and application thereof, wherein the preparation method comprises the following steps: s1, naturally cooling titanium slag generated after the smelting of the ore smelting electric furnace to 1100-800 ℃; s2, mixing the titanium slag with the temperature of 1100-; s3, after the sodium treatment reaction is ended, sequentially carrying out water washing, magnetic separation and gravity separation on the materials in the iron tank to obtain titanium-containing materials, wherein the magnetic separation is two-stage magnetic separation, the magnetic field intensity of one stage is 0.4T-0.8T, and the magnetic field intensity of the second stage is 1.3T-1.9T; s4, mixing the titanium-containing material obtained in the step S3 with dilute hydrochloric acid for acidification reaction to obtain TiO ₂ Precipitating, adding a certain amount of fluorite in the process of acidification reaction, and adding ammonium chloride crystals at the later stage of acidification reaction. The invention solves the problem of the existing titanium-rich material TiO ₂ Low grade and low acidolysis rate.

Description

Acid-soluble titanium-rich material, preparation method and application thereof

technical field

The invention relates to the technical field of metallurgy, in particular to an acid-soluble titanium-rich material and a preparation method and application thereof.

Background technique

In a broad sense, titanium-rich materials refer to materials rich in titanium dioxide (TiO ₂ ). The main raw materials used in the production of titanium dioxide and titanium sponge are titanium-rich ores. Titanium concentrate or titanium slag is generally used for the production of titanium dioxide by the sulfuric acid method. Titanium slag or artificial titanium is generally used in the production of titanium dioxide by the chloride method and the production of sponge titanium. Rutile is the raw material. Titanium-rich minerals or slag such as titanium slag and artificial rutile are generally referred to as titanium-rich materials, and such titanium-rich materials can usually be called titanium-rich materials in a narrow sense. Titanium-rich materials used in domestic industrial production are mainly titanium slag.

The mechanical beneficiation method can obtain high-grade titanium concentrate, but the content of calcium and magnesium impurities in the titanium concentrate is relatively high, and the content of calcium and magnesium oxides is usually higher than 6%, which seriously affects the quality of the product. Calcium in ilmenite concentrates exists in the form of impurity minerals or conjoined bodies, while magnesium mainly exists in the form of isomorphic substitution. The content of calcium and magnesium oxides in the acid-soluble titanium slag obtained by smelting this titanium concentrate is usually higher than 9%, which seriously increases the production load of titanium dioxide by the sulfuric acid method and reduces the quality of titanium dioxide.

The titanium-containing raw materials used in the production of titanium dioxide by the sulfuric acid method at home and abroad include titanium concentrate with a TiO ₂ content of about 47%, titanium slag with a TiO ₂ content of 72% to 76% (referred to as acid-soluble titanium slag), and titanium concentrate and titanium slag. For the mixture of titanium slag, the TiO ₂ content of acid-soluble titanium slag generally cannot exceed 76%, otherwise, the low-valent titanium generated by the over-reduction at high temperature in the electric furnace is difficult to be acidly hydrolyzed. The titanium-containing raw material used in the production process of titanium dioxide by chlorination method and sponge titanium at home and abroad can only be high titanium slag (referred to as titanium chloride slag) with a TiO ₂ content of more than 90%, otherwise, the impurity content in titanium tetrachloride is too large This results in unqualified products, equipment blockage and shutdown, and at the same time a large amount of waste residue is produced. The cost of artificial rutile is too high, few manufacturers produce it, and such products are rarely used in actual production. The production of titanium dioxide by the hydrochloric acid method has not yet been industrialized because it is difficult to find suitable titanium-containing raw materials.

The use of acid-soluble titanium slag as raw material for the production of titanium dioxide by the sulfuric acid method is an environmentally friendly choice and a development trend, which can greatly reduce the generation of ferrous sulfate and dilute waste sulfuric acid.

The existing acid-soluble titanium slag is usually produced by high-temperature smelting in an electric arc furnace. The raw material used is titanium concentrate, and the reducing agent is anthracite or petroleum coke. The technological process is as follows: the titanium concentrate and the reducing agent (such as coke) are mixed in a certain proportion, and then added to the submerged arc furnace after agglomeration. It is reduced to elemental iron, and other metal oxides cannot be reduced. After removing iron, acid-soluble titanium slag with TiO ₂ content (ω) 72% to 76% is obtained by crushing. At the same time, molten iron is cast into iron ingots for steelmaking or cast iron. Product production.

The _TiO2 grade of the existing acid-soluble titanium slag is not high, the content of calcium and magnesium is high, and it contains a certain amount of low-valent titanium. However, it has seriously affected the enthusiasm of titanium dioxide manufacturers to use slag.

The existing patent (CN103359781A) first performs a sodium reaction (melting and reacting ilmenite and sodium hydroxide to generate a solid phase mixture of sodium metatitanate), and then obtains a titanium-rich material through water washing, filtration, sorting and acidification. Although the TiO ₂ grade in the titanium-rich material is improved compared with the above reduction method, the TiO ₂ grade is still not high, and the acid hydrolysis rate is low.

Therefore, how to obtain a titanium-rich material with high TiO ₂ grade, no low-valent titanium (that is, high acid hydrolysis rate), and reasonable cost has become the eager expectation of sulfuric acid method titanium dioxide manufacturers.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of an acid-soluble titanium-rich material, so as to solve the problems of low TiO ₂ grade and low acidolysis rate of the existing titanium-rich material.

In addition, the present invention also provides the acid-soluble titanium-rich material produced by the above preparation method and its application.

The present invention is achieved through the following technical solutions:

The preparation method of acid-soluble titanium-rich material comprises the following steps:

S1. Naturally cool down the titanium slag produced by the submerged thermal electric furnace to 1100-800°C;

S2. Mix titanium slag with a temperature of 1100-800° C. and solid caustic soda in a certain proportion in the iron can to carry out sodium reaction. The reaction time is 20 to 60 minutes. In the later stage of the reaction, add NaCl solution to the iron can Air is blown into the material in the tank;

S3. After the sodiumization reaction is terminated, the materials in the iron can are washed with water, magnetically separated and re-selected to obtain titanium-containing materials. Among them, the magnetic separation is divided into two stages of magnetic separation, and the magnetic field strength of one stage is 0.4T-0.8T, and the The magnetic field strength of the segment is 1.3T-1.9T;

S4, mixing the titanium-containing material obtained in step S3 with dilute hydrochloric acid to carry out an acidification reaction to obtain TiO ₂ precipitation, adding a certain amount of fluorite during the acidification reaction, and adding ammonium chloride crystals in the later stage of the acidification reaction;

S5. The TiO ₂ precipitate obtained in step S4 is filtered, washed with water, and filtered by a plate and frame filter press to obtain an acid-soluble titanium-rich material.

Titanium slag manufacturers will stop the furnace, stop feeding, and stop power transmission after each submerged thermal electric furnace smelting is completed. Then, the titanium slag is scraped out from one outlet of the electric furnace, and the molten iron is released from the other outlet of the electric furnace until all the slag and iron are discharged. The raw material used in the present invention is the high-temperature molten titanium slag discharged on site from the slag outlet of the electric furnace of the manufacturer, and the temperature is about 1600°C.

The boiling point of NaOH is 1390°C, so as not to vaporize NaOH. Therefore, the temperature of the sodium reaction must be lower than 1390°C and lower than the range of 1390°C. The high-temperature titanium slag below 1390°C will quickly melt the caustic soda into a liquid state in the iron tank, as long as When the temperature is not lower than 350℃ (the melting point of NaOH is 318.4℃), NaOH will have a series of chemical reactions with the components of titanium slag, but in order to improve the conversion rate of titanium oxide, it is more suitable to control the temperature below 1100℃ (sodium titanate) The melting point is 1128°C, and the product is in a solid phase, which is conducive to the forward reaction). At this time, the product sodium titanate is in a solid phase, which is conducive to improving the conversion rate of the sodium reaction. When the temperature is lower than 800°C, the reaction speed is slow and requires a long time. reaction time.

In the present invention, in the later stage of the sodiumization reaction, NaCl solution is added into the iron can, and air is blown into the material in the iron can, and the Na ^ions in solution or molten Na ^ions will interact with the remaining components of the titanium slag. A series of chemical reactions (NaCl melting point is 801 ° C), one of the purposes of adding NaCl in the later stage is to further sodiumize the titanium slag components that have not been fully reacted, and the second purpose is to recycle the NaCl waste liquid produced in the subsequent process. The purpose of blowing in air is to increase the oxygen content in the molten material, accelerate the progress of the positive reaction, further promote the reaction process of NaOH and NaCl, and increase the rate of sodium ionization of low-valent titanium oxide Ti ₂ O ₃ into Na ₂ TiO ₃ . rate and conversion rate. If air is not blown, the reaction of low-valent titanium is not only slow, but also the conversion rate is low, which will seriously affect the production efficiency and product quality.

The specific reaction of NaOH is as follows:

2NaOH(l) _{+ TiO2} (s)= _Na2TiO3 (s)+ _H2O (g)

4NaOH(l)+ _Ti2O3 (s) _{+ 1} /2O2 _{= 2Na2TiO3} (s) ₊ 2H2O(g)

The resulting Na ₂ TiO ₃ (s) is insoluble in water.

Oxides such as SiO ₂ , MnO, Al ₂ O ₃ and V ₂ O ₅ react with NaOH to form soluble salts such as Na ₂ SiO ₃ , Na ₂ MnO ₄ , NaAlO ₂ , and NaVO ₃ respectively.

2NaOH(l)+ _SiO2 (s) ₌ Na2SiO3(s) _{+ H2O} (g)

2NaOH(l) ₊ MnO(s)+ _O2 = _Na2MnO4 (s)+ _H2O (g)

2NaOH(l) _{+ Al2O3} (s)=2NaAlO2(s) _{+ H2O} (g)

2NaOH(l) _{+ V2O5} (s)= _2NaVO3 (s)+ _H2O (g)

FeO, Fe, CaO, MgO will not react with NaOH, are inert, and remain in the slag in solid form.

The specific reaction of NaCl is as follows:

2NaCl(l) _{+ TiO2} (s)+ _H2O = _Na2TiO3 (s)+2HCl(g)

4NaCl(l)+Ti ₂ O ₃ (s)+2H ₂ O+1/2O ₂ =2Na ₂ TiO ₃ (s)+4HCl(g)

The resulting Na ₂ TiO ₃ (s) is insoluble in water.

Oxides such as SiO ₂ , MnO, Al ₂ O ₃ and V ₂ O ₅ react with NaCl to form soluble salts such as Na ₂ SiO ₃ , Na ₂ MnO ₄ , NaAlO ₂ , and NaVO ₃ respectively.

2NaCl(l)+SiO ₂ (s)+H ₂ O=Na ₂ SiO ₃ (s)+2HCl(g)

2NaCl(l)+MnO(s)+H ₂ O+O ₂ =Na ₂ MnO ₄ (s)+2HCl(g)

2NaCl(l)+Al ₂ O ₃ (s)+H ₂ O=2NaAlO ₂ (s)+2HCl(g)

2NaCl(l)+V ₂ O ₅ (s)+H ₂ O=2NaVO ₃ (s)+2HCl(g)

FeO, Fe, CaO, MgO will not react with NaCl, are inert, and remain in the slag in solid form.

During the reaction process, stirring is continuously performed, and the melting reaction time is controlled at 20-60 min. The higher the temperature, the shorter the required reaction time.

After the sodium reaction is completed, add water to the iron can, and wash the material repeatedly to remove soluble salts such as Na ₂ SiO ₃ , Na ₂ MnO ₄ , NaAlO ₂ , NaVO ₃ , and the remaining solid contains the following components: Na ₂ TiO ₃ , FeO, Fe, CaO, MgO, most of them are Na ₂ TiO ₃ , a small part is FeO and MgO, and the others are very few.

Among them, Na ₂ TiO ₃ exists in the form of hydrated sodium titanate. Na ₂ TiO ₃ is washed with water, and the Na ⁺ ions in it undergo ion exchange reaction with H ⁺ ions in water, and part of the Na ⁺ ions are leached into the liquid phase to form lye, leaving solid-phase hydrated sodium titanate. The reaction equation is as follows:

2Na ₂ TiO ₃ (s)+2H ₂ O(l)=Na ₂ O·2TiO ₂ ·H ₂ O(s)+2NaOH(l)

The NaOH generated here can be returned to the iron tank for recycling.

The above-mentioned solid phase is then subjected to conventional wet magnetic separation and re-selection to remove most of FeO and MgO to obtain a titanium-containing material with a very high content of Na ₂ O·2TiO ₂ ·H ₂ O(s).

The magnetic separation is divided into two stages of magnetic separation, the magnetic field strength of the first stage is 0.4T-0.8T, preferably 0.6T-0.7T, and the magnetic field strength of the second stage is 1.3T-1.9T, preferably 1.4T-1.7T. In the solid phase after the sodiumization reaction, in addition to FeO, there are some elemental iron powder and a small amount of unreduced Fe ₂ O ₃ . These iron oxides are combined with other metal oxides to form magnetite, titanium It exists in the form of magnetite, iron black titanium, hematite, perovskite and other phases. The reason why the first stage adopts weak magnetic separation and the second stage adopts strong magnetic separation is to avoid the magnetic blockage of the separation gap of the strong magnetic separator when removing strong magnetic minerals such as magnetite and semi-phantom hematite. To ensure that the strong magnetic separation goes forward, and at the same time, by using the weak magnetic separation process to discard a large number of strong magnetic minerals, such as magnetite, the minerals entering the strong magnetic separation are greatly reduced. Because the magnetic field of the strong magnetic separator is generally above 1T, and the minimum residual magnetic field is 0.05T, which is enough to attract strong magnetite, iron powder, etc. In addition, weak magnetic iron ores such as hematite, magnetite, semi-phantom hematite, etc., which are more or less always have strong magnetic properties, and the steel balls added in grinding are ground into iron powder, which is even more strong magnetic of. Therefore, even in the strong magnetic unloading area, it is difficult to completely remove the ore, which will cause magnetic blockage of the separation medium of the strong magnetic machine. The beneficial effect of using two-stage magnetic separation with reasonable strength is to remove iron-containing materials to the maximum extent, and at the same time to ensure the smooth operation of the magnetic separation process, and also to improve the operating efficiency of the magnetic separator and reduce power consumption.

A small amount of fluorite is added in the acidification reaction to remove the SiO ₂ that has not been completely sodiumized, and a solid-liquid mixture mainly containing TiO ₂ can be obtained.

The main reaction of acidification reaction is:

Na ₂ O·2TiO ₂ ·H ₂ O(s)+2HCl(l)=2TiO ₂ (s)+2NaCl+2H ₂ O

The NaCl produced here can be recycled back to the iron can.

Side reactions are:

FeO+2HCl=FeCl ₂ +H ₂ O

CaO+2HCl=CaCl ₂ +H ₂ O

MgO+2HCl=MgCl ₂ +H ₂ O

MgO in titanium-containing materials is easily soluble in dilute acid, so most of MgO can be removed. Since the MgO content in the high calcium magnesium titanium slag is as high as 6%, there will still be a small amount of MgO in the titanium-containing material. It is easy to volatilize after the reaction to generate ammonia, and it can remove MgO more thoroughly than dilute hydrochloric acid. The suitable mass fraction of NH ₄ Cl in the hydrochloric acid solution is 0.8%-1.3%.

Since the SiO ₂ in the titanium slag is much higher than that of MnO, Al ₂ O ₃ and V ₂ O ₅ , there will be a small amount of SiO ₂ that cannot generate Na ₂ SiO ₃ , so it must be removed. After adding a small amount of fluorite (the main component is calcium fluoride CaF ₂ ) in waste hydrochloric acid, a small amount of hydrofluoric acid will be generated. The reaction equation is as follows:

CaF ₂ +2HCl=CaCl ₂ +2HF

Hydrofluoric acid can react with silicon dioxide to generate gaseous silicon tetrafluoride. The reaction equation is as follows:

SiO ₂ (s)+4HF(aq)=SiF ₄ (g)↑+2H ₂ O(l)

The generated SiF ₄ can continue to react with excess HF to generate fluorosilicic acid, thereby removing SiO ₂ in solid TiO ₂ (s). The reaction equation is as follows:

SiF ₄ (g)+2HF(aq)=H ₂ [SiF ₆ ](aq)

After the soluble NaCl, FeCl ₂ , CaCl ₂ , MgCl ₂ , and H ₂ O are removed by conventional filtration, water washing, and plate and frame filter press filtration, the obtained near-solid titanium-rich material is mainly composed of TiO ₂ , and also contains a small amount of FeO and CaO. , MgO and other impurities.

Compared with ordinary acid-soluble titanium slag, the acid _- soluble titanium-rich material prepared by the method of the invention has the advantages that, firstly, the grade of _TiO2 is significantly improved _; The ₂ grade is greater than 98%, and the acid hydrolysis rate of the acid-soluble titanium-rich material is greater than 99%, which solves the problems of low TiO ₂ grade and low acid hydrolysis rate of the existing titanium-rich material.

Further, in step S1, the titanium slag is placed in a slag tank, and a refractory lining is arranged in the slag tank.

The high temperature of 1600°C can be avoided by setting the refractory lining to soften the tank wall.

Further, in step S2, the reaction time is 30-40 min.

Further, in step S2, the molar amount of solid caustic soda is 1.8 times the sum of the molar amounts of TiO ₂ , SiO ₂ , MnO, Al ₂ O ₃ and V ₂ O ₅ in the titanium slag and the molar amount of Ti ₂ O ₃ in the titanium slag. 3.6 times the sum.

The amount of solid caustic soda affects the _TiO2 grade in the prepared acid-soluble titanium-rich material.

Further, in step S2, the molar amount of the NaCl solution is 0.2 times the sum of the molar amounts of TiO ₂ , SiO ₂ , MnO, Al ₂ O ₃ and V ₂ O ₅ in the titanium slag and the molar amount of Ti ₂ O ₃ in the titanium slag. 0.4 times the sum of , the molar amount of NaCl solution is calculated as NaCl.

Further, in step S3, the magnetic field strength of the first stage is 0.6T-0.7T, and the magnetic field strength of the second stage is 1.4T-1.7T.

Further, in step S4, the dilute hydrochloric acid adopts the chlorination method to produce dilute waste hydrochloric acid by-product, and the added amount is 2.1 times the molar amount of the titanium-containing material hydrated sodium titanate, and in terms of HCl, the concentration of the dilute waste hydrochloric acid is 16% to 20%. The amount of fluorite added is 0.5 times the molar amount of SiO ₂ in the titanium slag, and the amount of ammonium chloride crystal added is 0.8%-1.3% of the mass fraction of dilute waste hydrochloric acid, and the mass fraction of dilute waste hydrochloric acid is calculated as HCl.

The dilute waste hydrochloric acid produced by the chlorination method is diluted to below 20% for use. The reaction time is 40-100 min, preferably 60-70 min. If the time is too short, the maturation is not sufficient, which affects the yield, and if the time is too long, the production efficiency is reduced. The concentration (ω) of dilute hydrochloric acid is 10% to 20%, preferably 16% to 20%. If the concentration is too low, the acidification reaction efficiency will be reduced, the reaction time will be prolonged, and the conversion rate of titanium will be affected. If the concentration exceeds 20%, it will become concentrated hydrochloric acid, which will produce strong volatilization, form smoke, and deteriorate the production environment.

Further, the NaOH solution produced by the washing in step S3 is concentrated and crystallized using the heat generated by the natural cooling of the titanium slag to obtain solid caustic soda crystals; the NaCl solution generated by the acidification reaction in the step S4 is concentrated and crystallized using the heat generated by the natural cooling of the titanium slag to obtain Solid NaCl crystals.

That is, the NaOH solution produced by water washing is transported to the concentration tank through the pipeline. The concentration tank is located above the titanium slag slag tank. The heat emitted by the cooling process of the high-temperature titanium slag is used to heat the concentration tank, evaporate the water in the NaOH solution, and control the appropriate temperature. The solid NaOH crystal is formed and returned to the titanium slag iron tank for repeated use.

That is, the NaCl solution generated by the acidification reaction is transported to the concentration tank through the pipeline, and the concentration tank is located above the titanium slag slag tank. The heat emitted by the cooling process of the high-temperature titanium slag is used to heat the concentration tank, control the appropriate temperature, and evaporate the water in the NaCl solution. The solid NaCl crystal is returned to the titanium slag iron tank for recycling.

The acid-soluble titanium-rich material, wherein the _TiO2 grade in the acid-soluble titanium-rich material is greater than 98%, and the acidolysis rate of the acid-soluble titanium-rich material is greater than 99%.

The acid-soluble titanium-rich material is used in the production of titanium dioxide by the sulfuric acid method.

When the acid-soluble titanium-rich material is used as the titanium source for the production of titanium dioxide by the sulfuric acid method, the consumption of sulfuric acid per unit of titanium dioxide product is significantly reduced, the acidolysis rate is significantly improved, the acidolysis residue is significantly reduced, and the source of impurities in the titanium dioxide product is significantly reduced. Medium concentration sulfuric acid can be used as acid hydrolysis acid, and the discharge of dilute waste sulfuric acid is greatly reduced.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. Compared with the common acid-soluble titanium slag, the acid-soluble titanium-rich material prepared by the method of the present invention has the advantages that the grade of TiO ₂ is significantly improved, and the acid-soluble titanium-rich material does not contain low-valent titanium oxide Ti ₂ O ₃ . The grade of medium _TiO2 is greater than 98%, and the acidolysis rate of the acid-soluble titanium-rich material is greater than 99%.

2. When the acid-soluble titanium-rich material prepared by the present invention is used as the titanium source for the production of titanium dioxide by the sulfuric acid method, the consumption of sulfuric acid per unit of titanium dioxide product is significantly reduced, the acid hydrolysis rate is significantly improved, the acid hydrolysis residue is significantly reduced, and the amount of the titanium dioxide in the titanium dioxide product is significantly reduced. The source of impurities is significantly reduced, and medium-concentration sulfuric acid can be used as acidolysis acid, and the discharge of dilute waste sulfuric acid is greatly reduced.

3. The present invention effectively utilizes the latent heat of the high-temperature titanium slag of the electric furnace, and effectively reuses the dilute waste hydrochloric acid of the chlorination method.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the examples. limit.

Example 1:

The preparation method of acid-soluble titanium-rich material comprises the following steps:

S1. Collect 1kg of molten acid-soluble titanium slag at a high temperature of 1500°C from the slag outlet of the titanium slag electric furnace during stable production at the Panzhihua Titanium Slag Plant, put it in a slag tank lined with high-temperature refractory materials, and naturally cool it down to At 1100°C, take 777.2g of flaky caustic soda and place it in an iron can with an iron inner surface;

The chemical composition (%) of titanium slag is shown in Table 1:

Table 1

S2, pour all the titanium slag with a temperature of 1100 ° C into the iron can for sodium reaction, stir continuously, and the reaction continues for 20min, then, add 126g of NaCl crystals into the iron can, and infuse into the material in the iron can Air, continue to react for 15min;

S3. After the sodiumization reaction is terminated, water is added to the iron tank, and the material is repeatedly washed with water until the washing liquid is neutral, and a solid mixture is filtered; is 0.6T, and the second-stage magnetic field strength is 1.5T. Obtain titanium-containing material and place it in a ceramic container;

The washed NaOH solution is sent to the concentration tank. The concentration tank is located above the titanium slag tank. The heat from the cooling process of the high-temperature titanium slag is used to heat the concentration tank to evaporate the water in the NaOH solution and control the appropriate temperature at the NaOH crystallization point. , to form solid NaOH crystals, which are returned to the titanium slag iron tank for repeated use. The reused amount is included in the above-mentioned 777.2 g of flaky caustic soda.

S4. Add 2085 g of dilute waste hydrochloric acid and 9 g of fluorite powder (calculated as CaF ₂ ) with a concentration of 18% (ω) by chlorination process into the above-mentioned ceramic container equipped with titanium-containing materials, and keep normal temperature (10-35 ° C) That is, continue stirring for 60min to end, and add 3.7g of ammonium chloride crystals 20min before the end of the reaction;

The acidified NaCl solution is sent to the concentration tank, which is located above the titanium slag tank, and the heat from the cooling process of the high-temperature titanium slag is used to heat the concentration tank, evaporate the water in the NaCl solution, and control the appropriate temperature at the NaCl crystallization point. , to form solid NaCl crystals, which are returned to the titanium slag iron tank for repeated use. The recycled amount is contained in the above-mentioned 126 g of NaCl crystals.

S5. The TiO ₂ precipitate obtained in step S4 is filtered, washed with water, and filtered by a plate and frame filter press to obtain an acid-soluble titanium-rich material.

The acid-soluble titanium-rich material prepared in this example was dried and tested. The TiO ₂ grade was 98.8%, the acid hydrolysis rate was 99.6%, and the low-valent titanium Ti ₂ O ₃ content was “trace”.

The measurement method of _TiO grade is as follows:

Dissolve 24.5 g of ammonium thiocyanate in 80 mL of hot water, filter, cool to room temperature and dilute to 100 mL, store in a closed dark bottle to obtain ammonium thiocyanate indicator. Weigh 30g of ferric ammonium sulfate into a 1000mL single-scale volumetric flask, add 300mL of water containing 15mL of sulfuric acid to dissolve. The potassium permanganate solution was added dropwise until the solution was pink. Dilute to volume with water and shake. Weigh 190mg-210mg of titanium dioxide standard reference material dried to constant weight at (105±2) °C, and calibrate the above solution according to the described steps. Calculate the titanium dioxide equivalent T1 of the solution, expressed in grams of equivalent TiO2 per milliliter:

In the formula: m1—the mass of the titanium dioxide standard reference substance used, in grams (g); ω (TiO2)—the titanium dioxide content of the standard reference substance, expressed in mass fraction; V1—the volume of the standard solution of ferric ammonium sulfate consumed by the titration , and the unit is milliliter (mL).

The measurement method of acid hydrolysis rate is as follows:

Get the acid-soluble titanium-rich material and place it in the acid hydrolysis tank, add 10.8mol of sulfuric acid (calculated as H ₂ SO ₄ ), carry out acidolysis reaction, the concentration of sulfuric acid is 75% (ω), the reaction temperature is 75 ° C, and the reaction time for 30min.

After the reaction is completed, the total titanium in the above-mentioned titanium liquid and the total titanium in the titanium-rich material product are measured successively, and the acid hydrolysis rate %=(total titanium in the solution)/(total titanium in the mineral powder)×100 is measured according to the formula. The solution rate was calculated to obtain an acid solution rate of 99.8%.

Example 2:

This embodiment is based on Embodiment 1, and the difference from Embodiment 1 is:

The temperature of the titanium slag during the sodium reaction was 800°C.

The acid-soluble titanium-rich material prepared in this example was dried and tested. The _TiO2 grade was 98.3%, the acid hydrolysis rate was 99.7%, and the low _- valent titanium _Ti2O3 content was "trace".

Example 3:

This embodiment is based on Embodiment 1, and the difference from Embodiment 1 is:

The temperature of the titanium slag during the sodium reaction was 1000°C.

The acid-soluble titanium-rich material prepared in this example was dried and tested. The TiO ₂ grade was 98.7%, the acid hydrolysis rate was 99.8%, and the low-valent titanium Ti ₂ O ₃ content was "trace".

Example 4:

This embodiment is based on Embodiment 1, and the difference from Embodiment 1 is:

The magnetic field strength of the first stage is 0.7T, and the magnetic field strength of the second stage is 1.7T.

The acid-soluble titanium-rich material prepared in this example was dried and tested. The TiO ₂ grade was 98.7%, the acid hydrolysis rate was 99.7%, and the low-valent titanium Ti ₂ O ₃ content was “trace”.

Example 5:

This embodiment is based on Embodiment 1, and the difference from Embodiment 1 is:

The magnetic field strength of the first stage is 0.5T, and the magnetic field strength of the second stage is 1.4T.

The acid-soluble titanium-rich material prepared in this example was dried and tested. The TiO ₂ grade was 98.3%, the acid hydrolysis rate was 99.6%, and the low-valent titanium Ti ₂ O ₃ content was “trace”.

Example 6:

This embodiment is based on Embodiment 1, and the difference from Embodiment 1 is:

In step S4, the concentration of by-product dilute waste hydrochloric acid of the chlorination method used is 16% (ω).

The acid-soluble titanium-rich material prepared in this example was dried and tested. The TiO ₂ grade was 98.5%, the acid hydrolysis rate was 99.5%, and the low-valent titanium Ti ₂ O ₃ content was “trace”.

Example 7:

This embodiment is based on Embodiment 1, and the difference from Embodiment 1 is:

In step S4, the concentration of dilute waste hydrochloric acid produced by the chlorination method used is 20% (ω).

The acid-soluble titanium-rich material prepared in this example was dried and tested, and the _TiO2 grade was 98.9%, the acid hydrolysis rate was 99.7%, and the low _- valent titanium _Ti2O3 content was "trace".

Comparative Example 1:

This comparative example is based on Example 1, and the difference from Example 1 is:

The temperature of the titanium slag during the sodium reaction was 1350°C.

The acid-soluble titanium-rich material product prepared in this comparative example was tested after drying, and the TiO ₂ grade was 92.1%, and the acid hydrolysis rate was 94.2%.

In this comparative example, the temperature of molten titanium slag is 1350°C, which is higher than the boiling point of caustic soda, so that it gasifies, so that the amount of caustic soda is insufficient, resulting in insufficient sodiumization reaction, which affects the _TiO2 grade of the titanium-rich material product, and also promotes low prices. Titanium content increased.

Comparative Example 2:

This comparative example is based on Example 1, and the difference from Example 1 is:

The temperature of the titanium slag during the sodium reaction was 600°C.

After drying the acid-soluble titanium-rich material product prepared in this comparative example, the TiO ₂ grade was 95.1%, and the acid hydrolysis rate was 96.3%.

In this comparative example, the temperature of the molten titanium slag is 600°C, and the temperature is too low, and the TiO ₂ grade and acidolysis rate are both reduced without prolonging the time.

Comparative Example 3:

This comparative example is based on Example 1, and the difference from Example 1 is:

In S4, add 1985 g of dilute waste hydrochloric acid and 9 g of fluorite powder (calculated as CaF ₂ ) with a concentration of 16% (ω) by chlorination process to the ceramic container containing the titanium-containing material to maintain normal temperature (10-35 ° C), i.e. Yes, continue stirring for 30min to end, and add 3.7g of ammonium chloride crystals 20min before the end of the reaction. Then carry out conventional filtration, water washing, and plate and frame filter press filtration to obtain titanium-rich material products

The acid-soluble titanium-rich material prepared in this comparative example was tested after drying, and the TiO ₂ grade was 94.5%, and the acid hydrolysis rate was 95.2%.

In this comparative example, when 1985g of dilute hydrochloric acid is not enough, and the concentration is reduced to 16% (ω), and the stirring time is not sufficient, the conversion rate of _TiO2 will be affected and the impurity content will be increased.

Comparative Example 4:

This comparative example is based on Example 1, and the difference from Example 1 is:

The magnetic field strength of the first stage is 0.3T, and the magnetic field strength of the second stage is 1.1T.

The acid-soluble titanium-rich material product prepared in this comparative example was tested after drying, and the TiO ₂ grade was 94.7%, and the acid hydrolysis rate was 94.9%.

In this comparative example, the strengths of the first-stage magnetic field and the second-stage magnetic field are lower than those of the present invention, resulting in that the weak magnetic separation cannot remove the strong magnetic minerals, and the strong magnetic separation cannot remove the weak magnetic minerals. The content of iron oxides and magnesium oxides Significantly increased, seriously affecting the TiO ₂ grade.

Comparative Example 5:

This comparative example is based on Example 1, and the difference from Example 1 is:

The magnetic field strength of the first stage is 0.9T, and the magnetic field strength of the second stage is 2.0T.

The acid-soluble titanium-rich material product prepared in this comparative example was tested after drying, and the TiO ₂ grade was 95.6%, and the acid hydrolysis rate was 95.3%.

In this comparative example, the strengths of the first-stage magnetic field and the second-stage magnetic field are higher than those of the present invention, so that the field strength is too high during weak magnetic separation, causing weak magnetic minerals to block the gap of the magnetic separator, and too much weak magnetic minerals are mixed during strong magnetic separation. In the working area of the magnetic separator, the removal effect of oxides such as iron and magnesium is significantly reduced.

Comparative Example 6:

This comparative example is based on Example 1, and the difference from Example 1 is:

The magnetic separation is not segmented, and the magnetic field strength is 1.5T.

The acid-soluble titanium-rich material product prepared in this comparative example was tested after drying, and the TiO ₂ grade was 95.4%, and the acid hydrolysis rate was 94.8%.

In this comparative example, the magnetic separation is not segmented, and the removal effect of iron-containing materials is not as good as that of the second-stage magnetic separation, resulting in a decrease in the TiO ₂ grade of the titanium-rich material product.

Comparative Example 7:

This comparative example is based on Example 1, and the difference from Example 1 is:

In step S2, air is not blown.

The acid-soluble titanium-rich material prepared in this comparative example was dried and tested. The _TiO2 grade was 95.3%, the low _- valent titanium _Ti2O3 content was 1.73%, and the acid hydrolysis rate was 97.9%.

In this comparative example, when NaOH, NaCl and low-valent titanium are melted and reacted, the conversion rate and conversion rate of low-valent titanium are reduced because air is not blown, resulting in a decrease in the grade of TiO ₂ in the titanium-rich material product, and the low-valent titanium content increased.

Comparative Example 8:

This comparative example is based on Example 1, and the difference from Example 1 is:

In step S4, the concentration of dilute waste hydrochloric acid produced by the chlorination method used is 14% (ω).

The acid-soluble titanium-rich material product prepared in this comparative example was tested after drying, and the TiO ₂ grade was 96.4%, and the acid hydrolysis rate was 97.7%.

In this comparative example, the concentration of dilute waste hydrochloric acid is lower than that of the present invention. Under the condition of constant acidification time, the reaction is not sufficient, the sodium titanate is not completely converted into TiO ₂ , and the impurity content increases.

Comparative Example 9:

This comparative example is based on Example 1, and the difference from Example 1 is:

In step S4, the concentration of dilute waste hydrochloric acid produced by the chlorination method used is 24% (ω).

The acid-soluble titanium-rich material prepared in this comparative example was tested after drying, and the TiO ₂ grade was 96.3% and the acid hydrolysis rate was 97.8%.

In this comparative example, the concentration of dilute waste hydrochloric acid is higher than that of the present invention, which causes a large amount of concentrated hydrochloric acid to volatilize, resulting in insufficient molar amount of effective HCl participating in the reaction, and the sodium titanate is not completely converted into TiO ₂ , the impurity content increases, and it also deteriorates. surroundings.

Comparative Example 10:

This comparative example is based on Example 1, and the difference from Example 1 is:

In step S4, fluorite powder is not added.

The acid-soluble titanium-rich material product prepared in this comparative example was tested after drying, and the TiO ₂ grade was 94.9%, and the acid hydrolysis rate was 96.3%.

Comparative Example 11:

This comparative example is based on Example 1, and the difference from Example 1 is:

In step S4, ammonium chloride crystals are not added.

The acid-soluble titanium-rich material product prepared in this comparative example was tested after drying, and the TiO ₂ grade was 95.1%, and the acid hydrolysis rate was 96.1%.

Comparative Example 12:

This comparative example is based on Example 1, and the difference from Example 1 is:

In step S4, fluorite powder and ammonium chloride crystals are not added at the same time.

The acid-soluble titanium-rich material product prepared in this comparative example was tested after drying, and the TiO ₂ grade was 93.2%, and the acidolysis rate was 94.4%.

Comparative Example 13:

1kg of molten acid-soluble titanium slag at a high temperature of 1500°C was collected from the slag outlet of the titanium slag electric furnace during the stable production of Pangang Titanium Smelter, placed in a slag tank lined with high temperature refractory materials, and cooled to room temperature for use. Then 14.3 mol of sulfuric acid (calculated as H ₂ SO ₄ ) was added to carry out acidolysis reaction, the concentration of sulfuric acid was 92% (ω), the reaction temperature was 75° C., and the reaction time was 30 min.

After the reaction is completed, the total titanium in the above-mentioned titanium liquid and the total titanium in the titanium-rich material product are measured successively, and the acid hydrolysis rate %=(total titanium in the solution)/(total titanium in the mineral powder)×100 is measured according to the formula. The solution rate was calculated, and the acid solution rate was 92.8%.

In this comparative example, the acid-soluble titanium slag product produced by the factory is used, even if the concentrated sulfuric acid with a high concentration is used for acid hydrolysis, the acid hydrolysis rate is not high due to the existence of a large amount of low-valent titanium.

Comparative Example 14:

1kg of molten acid-soluble titanium slag at a high temperature of 1500°C was collected from the slag outlet of the titanium slag electric furnace during the stable production of Pangang Titanium Smelter, placed in a slag tank lined with high temperature refractory materials, and cooled to room temperature for use. Then 14.3 mol of sulfuric acid (calculated as H ₂ SO ₄ ) was added to carry out acidolysis reaction, the concentration of sulfuric acid was 75% (ω), the reaction temperature was 75° C., and the reaction time was 30 min.

After the reaction is completed, the total titanium in the above-mentioned titanium liquid and the total titanium in the titanium-rich material product are measured successively, and the acid hydrolysis rate %=(total titanium in the solution)/(total titanium in the mineral powder)×100 is measured according to the formula. The solution rate was calculated, and the acid solution rate was 79.4%.

This experiment shows that when using factory-produced acid-soluble titanium slag products to produce titanium dioxide, when using sulfuric acid with the same concentration as Example 1 for acidolysis, the acidolysis rate is significantly reduced due to the presence of a large amount of low-valent titanium.

The specific embodiments described above further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. The preparation method of the acid-soluble titanium-rich material is characterized by comprising the following steps:

s1, naturally cooling titanium slag generated after the smelting of the ore smelting electric furnace to 800-1100 ℃;

s2, mixing the titanium slag with the temperature of 800-;

s3, after the sodium treatment reaction is ended, sequentially carrying out water washing, magnetic separation and gravity separation on the materials in the iron tank to obtain titanium-containing materials, wherein the magnetic separation is two-section magnetic separation, the magnetic field intensity of one section is 0.4T-0.8T, and the magnetic field intensity of the second section is 1.3T-1.9T;

s4, mixing the titanium-containing material obtained in the step S3 with dilute hydrochloric acid for acidification reaction to obtain TiO ₂ Precipitating, adding a certain amount of fluorite in the process of acidification reaction, and adding ammonium chloride crystals at the later stage of acidification reaction;

s5, mixing the TiO obtained in the step S4 ₂ Filtering, washing and filter-pressing by a plate-and-frame filter press to obtain an acid-soluble titanium-rich material;

in step S4, dilute saltThe acid adopts a chlorination method to produce a byproduct of dilute waste hydrochloric acid, the addition amount of the dilute waste hydrochloric acid is 2.1 times of the molar amount of the titanium-containing material sodium titanate hydrate, and the concentration of the dilute waste hydrochloric acid is 16-20% in terms of HCl; the addition amount of fluorite is SiO in the titanium slag ₂ The molar weight is 0.5 times, the addition amount of ammonium chloride crystals is 0.8-1.3% of the mass fraction of the dilute waste hydrochloric acid, and the mass fraction of the dilute waste hydrochloric acid is calculated by HCl.

2. The method for preparing the acid-soluble titanium-rich material as claimed in claim 1, wherein in step S1, the titanium slag is placed in a slag pot, and a refractory lining is disposed in the slag pot.

3. The method for preparing the acid-soluble titanium-rich material as claimed in claim 1, wherein the reaction time in step S2 is 30-40 min.

4. The method of claim 1, wherein in step S2, the molar amount of the solid caustic soda is TiO in the titanium slag ₂ 、SiO ₂ 、MnO、Al ₂ O ₃ And V ₂ O ₅ 1.8 times of the sum of the molar weight and Ti in the titanium slag ₂ O ₃ 3.6 times the sum of the molar weight.

5. The method of claim 1, wherein in step S2, the molar amount of NaCl solution is TiO in the titanium slag ₂ 、SiO ₂ 、MnO、Al ₂ O ₃ And V ₂ O ₅ The sum of the molar weight of the titanium slag and the Ti in the titanium slag is 0.2 time ₂ O ₃ 0.4 times of the total molar amount, the molar amount of the NaCl solution being calculated as NaCl.

6. The method of claim 1, wherein in step S3, the first magnetic field strength is 0.6T-0.7T, and the second magnetic field strength is 1.4T-1.7T.

7. The method for preparing the acid-soluble titanium-rich material as claimed in claim 1, wherein the NaOH solution generated by washing in step S3 is concentrated and crystallized by using the heat generated by naturally cooling the titanium slag to obtain solid caustic soda crystals; and S4, concentrating and crystallizing the NaCl solution generated by the acidification reaction by utilizing heat generated by natural cooling of the titanium slag to obtain solid NaCl crystals.

8. The acid-soluble titanium-rich material produced by the method for preparing the acid-soluble titanium-rich material according to any one of claims 1 to 7, wherein TiO in the acid-soluble titanium-rich material ₂ The grade is more than 98 percent, and the acidolysis rate of the acid-soluble titanium-rich material is more than 99 percent.

9. The acid-soluble titanium-rich material according to claim 8 is used for producing titanium dioxide by a sulfuric acid method.