FI65383C - FOERFARANDE FOER UTVINNING OCH SEPARERING AV METALLJONER T EX AV ZINK KOPPAR OCH JAERN MED ANVAENDNING AV FLYTANDE KATJONBYTARE - Google Patents

Description

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(71) (72) Gunnar Thorsen, Steinhaugen Ui, 7000 Trondheim, Norway-Norge (NO) (7U) Forssen & Salomaa Oy (5U) Method for the recovery and separation of metal ions, eg zinc, copper and iron, from liquid cation exchangers using - Förfarande för utvinning och separering av metalljoner, t.ex. of the zinc, head and side, with the addition of a fly ash

It is known that liquid organic cation exchangers such as, for example, fatty acids, naphthalene acids and other carboxylic acids, and alkane phosphoric acids such as diethylhexyl phosphoric acid (HDEHP) can be used to separate metal ions from aqueous solutions between metal ions and said organic substances. When the organic active components are present dissolved in an organic solvent which is insoluble in the aqueous phase, the contact between the organic and aqueous phases causes the formation of an organometallic compound between the active organic component and the metal ion in the aqueous phase. The organometallic compound thus formed is soluble in the organic phase but not in the aqueous phase, and the metal is thus extracted into the organic phase.

The formation of an organometallic compound takes place by cation exchange, whereby protons are released from the organic acid in equivalent amounts corresponding to the amount of metal to be extracted in the aqueous phase. This results in a corresponding decrease in the pH of the aqueous phase. Now, the formation of an organometallic compound depends primarily on the pH. As a general rule for carboxylic acids, it can be considered that the lower limit of extraction of metal ions is slightly lower than the pH at which the corresponding metals precipitate as hydroxides.

2 65383 This pH dependence causes the extraction to take place selectively, and the separation of metals is achieved by adjusting the pH in aqueous solution.

In the case of alkyl phosphoric acids, these can extract metal ions at lower pH values than carboxylic acids. In addition, special effects can arise, such as, for example, a change in the selectivity for copper and zinc in the transition from carboxylic acids to alkylphosphoric acid as a cation exchanger.

As a general rule, however, the extraction of metal ions by acidic cation exchangers results in the release of an equivalent amount of protons, and therefore only a very limited amount of metal ions can be extracted before this low pH is reached and the extraction ceases. This can be counteracted by neutralizing the released protons by introducing an alkali into the system. In this case, the pH remains at a level where the extraction of metal ions can continue.

In practice, however, this results in the use of the above-mentioned cation exchangers for extracting metal ions being in many cases prohibitively expensive or offering an economic advantage over the precipitation reaction, since the process requires the addition of an equivalent alkali corresponding to the amount of metal extracted.

The present invention relates to a process for recovering and separating metals from a metalloplastic raw material consisting of a solid material containing one or more metals zinc, copper, cadmium, nickel, cobalt, magnesium and iron, or from a metalloplastic raw material and an aqueous solution of metal salts, and t The process is characterized in that the metallic feedstock is extracted with a liquid cation bleach formed from an organic acid dissolved in an organic solvent to form one or more organometallic compounds by a reaction between a solid material and an organic phase, which compounds are then dissolved in an organic solvent. in the following liquid-liquid extraction process, in which the organic phase is contacted with a mineral acid for the selective removal of zinc and metals from organometallic compounds, or the organic phase containing 65383 organometallic compounds are contacted with an aqueous solution of metals to effect separation of the metals by exchange between the organic and aqueous metal solution.

The idea of the invention is based on a combination which involves the extraction of a metal-containing raw material with an organic acid (cation purifier) and the subsequent use of the organometallic compounds thus formed in a liquid-liquid extraction process. The extraction process uses said organic solution of metal complexes to recover and separate metal ions from an aqueous solution of metal salts. The aqueous solution of metal ions is normally derived from the extraction of the metal-containing raw material with a mineral acid, such as sulfuric acid, whereby a number of metals may enter the solution.

Figure 1 shows the principle of said method. To simplify the description, it is assumed in the figure that only two metals are dissolved when extracting the metal-containing raw material, but in principle the number of metals that can be recovered and separated using the present invention is not limited in any way.

In the reaction between the metal-containing feedstock and the boiler exchanger, the predominantly basic metal (Me ^.) In the feedstock reacts with the boiler exchanger (KH) to form an organometallic compound (K.Me ^.). Thereafter, in the next rivet-liquid extraction process, the least basic metal (Me 2) is extracted, switching to the organic phase in exchange with the metal Me 2, which exits into the aqueous phase. The metal is thus enriched in the aqueous phase during the Me 2 extraction process, while the Me 2 is transferred to the organic phase.

As the aqueous phase of metals Me ^. and Me ^ j. in addition to containing other metals, the metals can be extracted individually, possibly in groups, by appropriate partitioning of the organic phase and by adjusting the number of extraction stages within the technical execution of the extraction process.

Since the aqueous phase contains free millial acid, this free acid is neutralized to the extent appropriate by a corresponding increase in the amount of organic phase which is contacted with the aqueous phase during the 4,638,83 extraction process. The protons in the aqueous phase are then extracted in exchange with the basic metal from the organic phase.

It should also be noted that it is normally advantageous to dissolve as much of the metals as possible during the primary extraction with the organic phase. Excess organometallic compound can be taken directly to the Separation with mineral acid. Thus, the ideal system is to provide quantitative extraction of precious metals in the organic phase, after which the metals are separated by selective separation from the organic phase with a mineral acid, such as sulfuric acid.

According to Figure 1, by way of example, it has been assumed that the metals are alloyed from the release solution in metallic form by electrolysis. A number of alternative methods for treating aqueous solutions of these metal salts by reduction and precipitation processes are possible and these methods must be evaluated on a case-by-case basis. By carrying out the removal with an excess of concentrated mineral acid, it is thus possible to directly precipitate the metal salts in the separation process.

The present invention therefore relates to a process for recovering and separating metal ions, e.g. zinc, copper and iron, from an aqueous solution in the presence or absence of free mineral acid using a liquid cation bleach dissolved in a suitable organic solvent by combining the metal-containing feedstock with liquid extraction followed by liquid extraction. a liquid-liquid extraction process or a separation process, the process being characterized in that the liquid boiler exchanger is an organic acid, preferably a carboxylic acid or an alkane phosphoric acid, and in particular a carboxylic acid "Versatic 911", which is contacted and reacted with a metal-containing raw material, in a subsequent liquid-liquid extraction process to recover and separate metal ions from an aqueous solution of metals that are less basic than the metal / metals in the organic phase, or The inorganic compound is contacted directly with a mineral acid for selective metal removal.

As can be seen from Figure 1, the invention results in a closed process cycle with the possibility of quantitative recovery of precious metals in the metal holding material so that the part of the raw material which reacts with the cation exchanger is finally extracted with mineral acid or other aqueous liquid.

The following is an example of how the invention can be used in the hydrometallurgical production of zinc, where the metallic raw material exists in a form known as "calcine" which is prepared by roasting sulfide concentrates. In this case, the zinc oxide contained in the calcine reacts with the organic acid to form an organometallic compound of zinc, which is then used to remove ferrous metals from the acidic zinc sulfate solution within the heat extraction stage of the process.

However, the general principle of the invention can be used in the context of any hydro-metallurgical process in which it is possible to prepare an organometallic compound by reaction between a solid metal-containing raw material and an active organic extraction component. In previously known hydrometallurgical processes, reference may be made, for example, to the purification and purification of metals such as copper, nickel, cobalt and zinc from sulphide and oxide ores. In the case of sulphide ores, the raw material is most often pre-roasted with metal oxide (calcine), which is essentially the starting material of the present invention.

When the process according to the invention is used, for example, in the hydrometallurgical production of zinc, in which, as is known, zinc oxide in calcine is dissolved in sulfuric acid and zinc is electrolytically doped, the process can be used to remove iron from zinc sulphate solution without any consumption of alkali or other additives.

This is further illustrated in the following, where, for example, it is assumed that the liquid cationic foam is a commercial carboxylic acid such as "Versatic 911" (Shell), hereinafter referred to as "Versatic", which exists as a solution dissolved in a suitable organic solvent.

Figure 2 shows the principle of the method mentioned below. In the figure, KH corresponds to "Versatic" acid.

"Versatic" in its acid form is reactive with solid zinc oxide (calcine). The reaction forms a metal compound between zinc and 6 65383 "Versatic" (Zn-Versatic). Thereafter, when the zinc-plated organic phase and the iron-containing aqueous zinc sulfate solution come into contact with each other, a valence reaction between zinc and iron occurs. In this case, the iron enters the organic phase, where it is present as the metal compound Fe-Versatic. In the exchange reactor, an equivalent amount of zinc is transferred from the organic phase to the zinc sulfate water solution. In this way, iron is quantitatively removed from the zinc sulphate solution in contact between the two immiscible phases in one or more stages, depending on the technical performance of the extraction process.

After extraction, the organic phase can be liberated from the iron by contacting it with sulfuric acid or another mineral acid in one or more degrees. The cation exchanger ("Versatic") then regenerates to its acid form and is again ready to be charged with zinc in reaction with solid zinc oxide (calcine).

As can be seen from the above method, the raw material, in this case zinc oxide, acts as an alkali and the use of special chemicals is unnecessary. In the reaction between "Versatic" and calcine, zinc dissolves in the organic phase and is subsequently precipitated as a metal in the electrolysis, after being transferred to the aqueous phase in the extraction step.

Norwegian Patent No. 108,047 discloses a process for separating iron from metal sulphate solutions and a hydrometallurgical process for the production of zinc. This patent refers to conventional processes used in the hydrometallurgical production of zinc.

That patent states that the extraction of calcine with sulfuric acid takes place in two stages, the first stage being characterized as neutral extraction and the second stage as acidic extraction.

In the first stage, an excess of calcine is added so that the extraction will be relatively mild. In this case, the iron el enters the solution and a non-ferrous einclsulfate solution is obtained. However, the remaining calcine contains significant amounts of zinc bound to iron in the form of zinc ferrites. To increase the total yield of zinc, this residue is subjected to a vigorous extraction process by heating with excess sulfuric acid 655383, which is termed acidic extraction. In this case, the remaining amount of zinc goes into the solution, but at the same time considerable amounts of iron also accompany the solution.

Norwegian Patent No. 108,047 shows how this iron can be precipitated as a basic sulfate in an acidic solution in the presence of cations such as K +, Na * or NH 4. This precipitation product is called jarosite and said patent provides the basis for a so-called jarosite process in the hydro-metallurgical production of zinc. This process is used in a number of zinc plants and one of its advantages over previous processes is that iron is not a limiting factor in extraction yield in calcine acid treatment,

The process according to the invention, which is based on a combination formed between the reaction between calcine and an organic cation exchanger and the subsequent liquid-liquid extraction to remove iron by means of an organometallic zinc complex formed from a zinc sulphate solution, is particularly suitable for zinc hydrometallurgical production. The invention can be based on and based on the two-stage extraction process which forms the basis of the bridging process.

However, the process according to the invention has obvious advantages over the refining process in that it is not necessary to add el from a chemical, such as ammonia, to form a precipitation product. Furthermore, in the present method, iron can be taken out of the process loop in alternative forms. The removal of charged organic Fe-Versatlc is a very flexible step, where it is possible, for example, to prepare a very suitable starting material for the further processing of iron into high-grade iron powder or electrolyte-steel. Iron can be crystallized out as ferrous sulfate from the release fluid, where the ferrous sulfate concentration can be kept close to the saturation concentration. Since crystallization is more advantageous as divalent ferrous sulfate, the iron can be reduced with e.g. sulfur dioxide before precipitation.

In principle, there are no restrictions on the amounts of iron that can be removed from the zinc sulfate solution. It should also be emphasized that the excess free sulfuric acid from the strongly acidic solution can be neutralized as one step in the extraction process. This means that prior partial neutralization with calcine, which is e.g. normal practice in the precipitation of iron in the jarosite process, is unnecessary. Thus, the yield of zinc as well as the recovery of other metals in the ores is limited only by the extent to which it is possible to bring the metals into solution in the extraction processes.

A particular advantage of the method according to the invention is that it forms the basis for a very environmentally friendly process.

It should also be emphasized that the removal and separation of non-ferrous metals from the zinc sulphate solution is well supplied within the extraction process. In particular, copper can be extracted according to the same principle as described above for iron extraction. The mixture of copper, zinc and iron can thus be separated by using the zinc-containing organic solution first to extract the iron and then to extract the copper. This is further illustrated by the application below for the treatment of mining water.

When copper is the major component in the metal-containing feedstock, copper reacts with an organic cation bleach and can be used in the same manner as an organic zinc complex to extract iron from a metal brine.

It should be clarified that the process according to the invention is limited to the hydrometallurgical production of zinc and copper, but encompasses all areas where it is possible to use said combination of extraction of a metal-free raw material with an organic cation bleach and subsequent liquid-liquid extraction to separate metals from water. from a solution formed in the conventional extraction of the raw material with mineral acid.

Said combination of extraction and liquid-liquid extraction can also be used in connection with the separation and recovery of metal ions from such solutions which are not directly related to the production of metals from a solid raw material. Examples are metal-plated wastewater and used pickling baths in the metal industry after chemical surface treatment, as well as other metal-plutonium waste liquids, such as, for example, mine effluents.

9 65383 In these cases, however, the solid which is reactive with the organic acid (cation exchanger) must be added to the process loop, e.g. in the form of lime. Because the metal solution is sulfate-based, an equivalent amount of gypsum precipitates relative to the metal elements that are recovered.

This method is, for example, very suitable for the recovery and separation of precious metals from mining waters, in which, for example, 0.5 to 1.0 g / l of copper, 1 to 2 g / l of zinc and 5 to 6 g / l of iron can be presented as a characteristic composition.

Figure 3 shows, by way of example, a process diagram for the recovery and separation of copper, zinc and iron from membrane water, where the metals are present as sulphates. As the extraction components, for example, "Versa-tic" can be used. In the first stage for the neete-liquid extraction, iron separates from the alloy and in the next stage, copper can separate from the zinc. The zinc concentration of the remaining zinc sulphate solution is equivalent to the combined total concentration of the original zinc, copper and iron and any free sulfuric acid. From this zinc sulphate solution, a branch stream can be taken to be treated with lime and used to form an organometallic zinc compound which is used in liquid-liquid extraction.

When the present method is used to treat spent etching baths containing relatively high concentrations of zinc and iron mixed, e.g., the aforementioned Zn-Versatick complex can be used as a liquid-liquid extraction element to separate iron from a pickling bath. After this treatment, the bath is formed by a zinc salt solution from which zinc can be alloyed and recovered pure.

The invention is explained in more detail below by means of examples.

Example 1 200 g of technical calcine prepared by roasting zinc sulphide concentrate were contacted with 1 liter of an organic phase consisting of 30% "Vereatic 91]" dissolved in "Shellsol TD". After stirring for 20 min at 50 ° C, the solid and liquid phases were separated. The organic phase now had a zinc concentration of 40 g / l.

ίο 65 38 3

In a mixing vessel, 100 ml of an aqueous sulfate solution containing 120 g / l of zinc and 18 g / l of iron was contacted with 317 ml of the above-mentioned 30% Versatic solution. 83 ml of zinc-loaded Versatic solution containing 40 g / l of zinc are then gradually added, and after an hour of contact time at 20 ° C, the aqueous and organic phases are separated. Analysis of both phases gave the following results:

Aqueous phase 152.0 g / l Zn 0.3 g / l Fe

Organic phase 0.4 g / l Zn 4.42 g / l Fe

Example 2

From the aqueous sulfate solution containing 120 g / l zinc and 18 g / l iron, the iron was continuously extracted in an apparatus consisting of three "stirrer-precipitators" connected in series at 50 ° C. The organic phase was divided into two streams, a pure 30 Z Versatic solution (Org.-1) and a zinc-loaded 30 Z Versatic solution (0rg.-2) containing 40 g / l zinc. The organic solvent was "Shellsol TD".

The aqueous phase and the Org.-1 solution were introduced into the first and last stages, respectively, while the Org, -2-l solution was partitioned between the three stages.

Relative total feed rate:

Aqueous solution: Org.-1: Org.-2 * 1: 2.2: 0.8.

The effluent single sulphate aqueous solution contains 152 g / l Zn and less than 0.1 g / l Fe.

Example 3

From the sulfuric acid grade sulfate containing 120 g / l zinc and 18 g / l iron and 25 g / l free sulfuric acid, both iron and free protons were extracted continuously in the same manner as in Example 2.

Relative total feed rate: 11 65383

Aqueous solution: Org.-1: 0rg.-2 «* 1: 1.8: 1.2.

The nearby aqueous solution of single sulfate contained 169 g / l Zn and less than 0.1 g / l

Pe.

Example 4 100 g of metal oxide were contacted with 1 liter of an organic phase consisting of 30% cation exchanger dissolved in "Shellsol TD" liquid. After stirring for 20 min at 50 ° C, the solid and liquid phases were separated and the metal concentration was measured in the organic phase.

The results are shown in Table 1 below.

Table 1. Metal concentration g / l in the organic phase after contact with metal hydroxides.

Metal oxide Cation exchanger

Vereatic 911 Diethylhexylphosphoric acid (HDEHP)

CuO 1.56 0.53

Ni 2 O 3 1.50 0.57

NiO 0.22 0.15

Example 5

A mixture of 75 g ZnO and 75 g CuO was contacted with 1 liter of the organic phase formed by 10 Z Versatic 911 dissolved in Shellsol TD. After stirring for 20 min at 50 ° C, the organic phase contained 27 g / l Zn and 0.02 g / l Cu.

Example 6

A mixture containing 25 g / l * H-2 ° 3 3a 25 8 CuO * 8 was contacted at 30 ° C with the organic phase according to Example 5. The metal concentration in the organic phase after 20 min was 0.35 g / l Ni and 0.03 g / l Cu.

65383

Example 7 To 1 liter of a zinc sulfate solution containing 15 g / l Zn was added an equivalent amount of solid calcium hydroxide corresponding to 9.2 g Ca. After stirring for 5 hours at 20 ° C, the precipitate was filtered off from the aqueous phase. The filter cake, consisting of gypsum and precipitated hydroxide, was divided into two equal parts and each transferred to its own mixing range. Each aliquot was contacted with 400 ml of 30% Versatlc 911 resp. 30% HDEHP dissolved in Shellsol TD fluid. After stirring for 30 min at 20 ° C, the zinc concentration in both organic solutions was: 30% Versatlc 911: 15.1 g / l Zn 30 HDEHP: 14.9 g / l Zn.

Example 8 100 g of calcium and magnesium oxide, respectively, were each slurried in 1 liter of water. The slurry phase was contacted with 1 liter of the organic phase containing 30 Z of Versatlc® 911 dissolved in Shellsol ®TD. The temperature was 25 ° C.

After stirring for 1 minute, the organic phase showed a metal concentration of 20 g / l for calcium and 16 g / l for magnesium, respectively.

Example 9 5 g of finely ground powdered metal was contacted with 400 ml of an organic phase containing 30 Z of cation exchanger (R) dissolved in Shellsol® TD. 400 ml of water was also present in the system and the experiment was performed in an oxygen gas space.

After stirring for 15 minutes and 120 minutes at 50 ° C, respectively, the solid and liquid phases were separated and the metal concentrations in the organic phase were measured.

The result is shown in Table 2 below.

13 65383

Table 2

Percentage of dissolved metal in the organic phase according to contact with pure metal powder% of metal dissolved in the organic phase (k)

Metal Versaticw911 ethylhexylphosphoric acid (HDEHP) 15 min 120 min 15 min 120 min

Zn 96 98 88.5 98.5

Cu 4 48 82 98

Ni 0.4 0.4 44 76

Example 10

The metal material formed in the cementation process in the hydro-metallurgical production of zinc was formed from a number of metals oxidized at 300 ° C by heating in air. The metals in the oxidized material contained the following percentages:

Cu Zn Cd Nl Co As Sb 22.8 34.3 7.9 0.1 0.1 0.1 0.25 75 g of solid oxidized material was contacted with 2 liters of organic phase, containing 30% of a cathlon bleach dissolved in Shellsol®TD. material. The system also included 0.5 liters of water.

After stirring for 4 hours at 50 ° C, the solid material present was separated off and the metal concentrations were measured. The result is shown in Table 3 below.

14 65383

Table 3

Percentage of metal dissolved in a solid oxidized material with a boiler.

Elements Cu Zn Cd Ni Co As Sb

Versatic ® 911 93.0 67.2 87.8 68.0 79.9 not measured diethylhexyl 99.5 99.7 99.4 96.4 94.2 96.2 62.0 phosphoric acid (HDEHP)

Example 11 200 g of sulfated copper concentrate, containing 27% copper, was contacted with 1 liter of an organic phase containing 30 X of diethylhexylphosphoric acid (HDEHP) dissolved in Shellsol® TD. The system also included 200 ml of water. The experiment was performed by stirring in an oxygen environment at 70 ° C.

After 2 hours, it was found that 1.8% of the copper was dissolved in the solid material.

Claims (8)

A process for the extraction and separation of metals from a metal-containing raw material, which consists of a solid material containing one or more of the metals zinc, copper, cadmium, nickel, cobalt, magnesium and iron, or from a metal-containing rigod and a aqueous solution of metal salts, characterized in that the metal-containing raw material is leached with a liquid cation exchanger, which is an organic acid dissolved in an organic solvent, one or more metal-organic compounds being formed by reaction between solids and the organic phase, which compounds are dissolved. in the organic solvent, and then used in a subsequent liquid-liquid extraction process, wherein the organic phase is contacted with a mineral acid to selectively remove zinc and the metals from the metallic organic compounds, or the organic phase containing the metallic organic compounds. , is brought into contact with an aqueous solution of metals, thereby obtaining a separation of the metals by exchange between the organic and the aqueous metal solution. Process according to claim 1, characterized in that the metals in the aqueous metal solution belt or partly originate from the same solid raw material used to form the metallic organic compounds, and that the aqueous solution of the metals is prepared by subjecting the raw material to a leaching with a mineral acid. , such as sulfuric acid or other aqueous leaching liquid. 3. A process according to claims 1-2, characterized in that after the reaction with the liquid cation exchanger, the solid solid material is subjected to a leaching with a mineral acid, such as sulfuric acid, or another aqueous leaching liquid for the recovery of residual metals and the aqueous metal solution thus obtained. or partially constitutes the aqueous phase of the liquid-liquid extraction process. Process according to claims 1-3, characterized in that the liquid cation exchanger, which is an organic acid, is a carboxylic acid or an alkane-phosphoric acid.