Method for directly and selectively extracting indium from high-iron indium-containing solution without reduction

Abstract

The invention discloses a method for directly and selectively extracting indium from a high-iron indium-containing solution without reduction, which comprises the following steps: mixing the high-iron zinc indium-containing solution obtained by acid leaching of zinc oxide with a composite extractant, extracting, separating to obtain an indium-iron-containing organic phase, adding a detergent into the indium-iron-containing organic phase for washing, and separating to obtain a zinc-removed indium-iron-containing organic phase, the method comprises the following steps: adding a composite extractant into a high-iron-zinc indium-containing solution, then adding a stripping agent to carry out indium stripping to obtain an indium-containing stripping solution so as to realize the separation of indium in the high-iron-zinc indium-containing solution, and the composite extractant consists of 10-40% by volume of a phosphate extractant A, 5-20% by volume of a phosphoric acid synergistic extractant B and 40-85% by volume of sulfonated kerosene. According to the method, ferric iron does not need to be reduced, the indium-iron separation coefficient is high, extraction is not prone to emulsification, and the indium recovery rate is high.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for directly selectively extracting indium from a high-iron indium-containing solution without reduction. Background Art

[0002] Indium is a rare metal located in Group IIIA of the periodic table. It is one of the most scarce metals in the world. Its application in high-tech fields such as weapons manufacturing, aerospace, and information industry is indispensable. In recent years, due to its physical and chemical properties such as light permeability and strong conductivity, indium has been widely used in ITO targets, electronic semiconductors, high-performance indium alloys, photovoltaic cells, modern military and other high-tech fields.

[0003] The content of indium in the earth's crust is extremely small (0.11μg / g), and it cannot form minerals independently. It is only associated with trace amounts of metal ores such as zinc and lead. At present, the raw materials for producing indium mainly come from zinc leaching slag, and the amount of indium can reach 512t / a, which is of considerable value. The common treatment process is "volatilization roasting-acid leaching-extraction-electrolysis". The supernatant of volatile smoke acid leaching usually contains a large amount of iron and zinc, and the concentration of indium ions is relatively low. Since the properties of trivalent iron ions and indium ions are similar, it is difficult to separate and enrich indium from the acid supernatant. At present, the trivalent iron ions in the solution are usually reduced to divalent iron ions first, and the characteristics of the large difference in the properties of indium and divalent iron are used to extract indium with a single extraction system of P204. There are problems such as complex process, easy emulsification during the extraction process, slow phase separation, incomplete reduction, and easy co-extraction of iron. In addition, there is the possibility of producing arsenic-containing highly toxic compound gas during the reduction process.

[0004] Chinese patent document CN109943720A discloses a method for comprehensive recovery of zinc and indium from a low-indium, high-iron zinc-containing solution, which uses "goethite method for iron removal - deep reduction of iron filings - P204 extraction - zinc powder replacement" to obtain crude indium, which can achieve indium and iron separation and indium enrichment, but the method requires pre-iron removal and deep reduction of iron, and has problems such as incomplete trivalent iron reduction, large amount of iron powder, and slow extraction phase separation; Chinese patent document CN105018752A discloses a method for separation, enrichment and recovery of indium from a low-concentration indium sulfate solution, which uses a step-by-step extraction method of "P204 extraction - hydrochloric acid stripping - TBP extraction - sulfuric acid stripping" to obtain a high-concentration indium sulfate solution, which achieves The enrichment and separation of indium, but the method has the problems of long process flow and poor extraction selectivity; Chinese patent documents CN113373323A and CN102061398A adopt the method of "first extracting iron removal, then extracting indium" to achieve indium-iron separation, and the indium-iron separation effect is good, but the process flow is long, the cost of iron removal is high, and the back extraction acid consumption is large; Chinese patent document CN105018753A discloses a composite extractant and a method for extracting, separating and recovering indium with the composite extractant, using zinc leaching residue reduction leaching solution as the stock solution, and using the composite extractant to selectively extract indium, the stock solution is reduced during the leaching process, and the iron in the treated solution is mainly present as divalent iron ions.

[0005] The above technologies all require the prior removal of iron or reduction of trivalent iron, which results in long process flow, high cost of iron disposal in the solution, and easy oxidation of iron during the extraction process, resulting in emulsification. It is urgent to develop a new method for direct selective extraction of indium from high-iron indium-containing solution without reduction. Summary of the invention

[0006] In order to overcome the problems in the prior art, the present invention provides a method for directly selectively extracting indium from a high-iron indium solution without reduction. The method of the present invention does not require the reduction of trivalent iron, has a high indium-iron separation coefficient, is not easy to emulsify, and has a high indium recovery rate.

[0007] In order to solve the above technical problems, the technical solution proposed by the present invention is: The present invention provides a method for directly selectively extracting indium from a high-iron indium-containing solution without reduction, comprising the following steps: S1. Mixing the high-iron zinc-containing indium solution obtained after acid leaching of zinc oxide with a composite extractant, extracting and separating to obtain an indium-containing iron organic phase; the high-iron zinc-containing indium solution is not subjected to reduction treatment, and the composite extractant is composed of 10% to 40% by volume of a phosphate extractant A, 5% to 20% of a phosphoric acid co-extractant B, and 40% to 85% of sulfonated kerosene; S2. Add a detergent to the indium-iron organic phase for washing, separate and obtain the indium-iron organic phase after zinc removal, then add a stripping agent to strip indium to obtain an indium-containing stripping solution, thereby achieving the separation of indium in the high-iron-zinc indium-containing solution.

[0008] In the present invention, the high-iron zinc indium solution obtained after the acid leaching of zinc oxide is treated, and the high-iron zinc indium solution without reduction treatment contains a large amount of trivalent iron ions. The high-iron zinc indium solution is extracted by a composite extractant. The phosphate extractant A has the ability to extract both indium and iron, but the extraction speed of the phosphate extractant A for indium is faster than that for iron. At the same time, the addition of the phosphoric acid co-extractant B can better inhibit the extraction of iron by the extractant, eliminate the emulsification phenomenon that occurs when the pure phosphate extractant A extracts iron, and control the phosphate extractant A and the phosphoric acid co-extractant B within the above range to ensure that indium is preferentially extracted and iron is extracted in small amounts. Sulfonated kerosene is used as a diluent, and its function is to improve the physical properties of the extractant, and has good solubility for the extractant and the extractant, which is conducive to the separation and clarification of the two phases. A detergent is added to the indium-containing iron organic phase obtained after extraction to mainly remove zinc and other impurities, and then stripping is performed to obtain an indium-containing stripping solution containing trace iron impurities, thereby achieving the separation of iron, zinc and indium.

[0009] As an optional embodiment, in the method provided by the present invention, in step S2, an iron-containing organic phase is also obtained after back extraction, an acid washing agent is added to the iron-containing organic phase, and a washed organic phase is obtained after acid washing, and then an anti-iron agent is added to the washed organic phase, and an anti-iron liquid and an organic phase are obtained after back extraction, and the anti-iron liquid is used for the preparation of iron; the organic phase is a composite extractant, which is used for the extraction of the high-iron zinc-indium-containing solution in step S1.

[0010] The iron-containing organic phase obtained after stripping is treated with acid washing, and the obtained acid washing liquid is recycled and reused as an acid washing agent. The organic phase obtained after stripping is treated with iron removal, and the organic phase after iron removal is a composite extractant, which can be recycled and continued to be used for the extraction of high-iron zinc-containing indium solution, thereby realizing the recycling of the organic phase.

[0011] As an optional embodiment, in the method provided by the present invention, the phosphate ester extractant A is selected from one or more of 2-ethylhexyl phosphate mono-2-ethylhexyl ester, di(2-ethylhexyl) phosphate, bis(2,4,4-trimethylpentyl)phosphonic acid, and 1,3-dioctyl-2-thiourea.

[0012] As an optional embodiment, in the method provided by the present invention, the phosphoric acid synergist B is selected from one or more of trioctyl phosphine oxide, tributyl phosphate, trialkyl phosphine oxide, and dimethylheptyl methylphosphonate.

[0013] As an optional embodiment, in the method provided by the present invention, in step S1, the volume ratio of the high-iron-zinc-indium-containing solution to the composite extractant is 1:1~3:1.

[0014] In the present invention, the volume ratio of the extractant to the solution is O / A. A too large ratio will lead to waste of the extractant and reduce the processing efficiency, while a too small ratio will lead to poor extraction effect.

[0015] As an optional embodiment, in the method provided by the present invention, in step S1, the extraction time is 1 to 3 minutes, and the number of extraction stages is 2 to 5.

[0016] In the present invention, since the extraction rate of indium by the phosphate extractant A is faster than that of iron, the extraction time, that is, the difference in extraction kinetics between indium and iron, is controlled to further achieve the separation of indium and iron.

[0017] As an optional embodiment, in the method provided by the present invention, a zinc-containing raffinate is also obtained in step S1, and the zinc-containing raffinate is used for zinc recovery.

[0018] As an optional embodiment, in the method provided by the present invention, in step S2, the detergent is selected from one of sulfuric acid, hydrochloric acid or oxalic acid; the volume ratio of the detergent to the indium iron-containing organic phase is 20:1~50:1.

[0019] The purpose of the detergent in the present invention is to remove zinc in the organic phase in advance. If the stripping is performed directly without washing, the zinc will enter the stripping solution, making the stripping solution composition complex and affecting the subsequent impurity removal.

[0020] As an optional embodiment, in the method provided by the present invention, the detergent concentration is 1-3 mol / L, the washing time is 1-5 min, and the washing level is 1-4.

[0021] As an optional embodiment, in the method provided by the present invention, in step S2, the stripping agent is selected from one of sulfuric acid, hydrochloric acid or oxalic acid; the volume ratio of the stripping agent to the indium iron-containing organic phase is 10:1~30:1.

[0022] As an optional embodiment, in the method provided by the present invention, the concentration of the stripping agent is 2-5 mol / L, the stripping time is 1-5 min; and the stripping stage is 5-10.

[0023] As an optional embodiment, in the method provided by the present invention, a zinc-containing raffinate is also obtained in step S1, and the zinc-containing raffinate is used for zinc recovery.

[0024] As an optional embodiment, in the method provided by the present invention, in step S2, the obtained indium-containing stripping solution is adjusted to a pH of 2 to 4 by adding alkali to remove trace bismuth and iron in the solution, or is used as a stock solution for electrolytic indium to prepare crude indium.

[0025] As an optional embodiment, in the method provided by the present invention, the acid cleaning agent is selected from pure water or tap water, and the volume ratio of the acid cleaning agent to the iron-containing organic phase is 5:1~15:1.

[0026] As an optional embodiment, in the method provided by the present invention, the anti-iron agent is selected from one of sulfuric acid, hydrochloric acid or oxalic acid, the concentration of the anti-iron agent is 0.5~1.5 mol / L, the volume ratio of the anti-iron agent to the iron-containing organic phase is 1:1~3:1, and the temperature is 30~50°C.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention does not reduce or remove iron, but directly uses a composite extractant to extract indium. The phosphoric acid co-extractant B is added to the phosphate ester extractant A, which inhibits the extraction of iron by the phosphate ester extractant A, greatly improves the indium-iron separation coefficient, and eliminates the emulsification phenomenon that will occur during the extraction of the phosphate ester extractant A. The extraction capacity of the extractant is improved, and the indium-iron separation effect is good.

[0028] (2) The present invention avoids the step of using zinc powder or iron powder to reduce the indium-containing liquid in the prior art, thereby reducing losses and saving costs.

[0029] (3) The present invention improves the subsequent iron removal step, avoids the damage to the environment and organic matter caused by high-concentration hydrochloric acid iron removal, improves the working environment, and improves the recycling performance of the extractant. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a technical roadmap for the short-process extraction and enrichment of high-iron indium-containing solution of the present invention. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0033] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0034] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0035] Example 1 A method for directly selectively extracting indium from a high-iron indium solution without reduction, the process is as follows Figure 1 As shown, this method uses the high-iron indium solution obtained in the production process of a domestic zinc smelting enterprise as raw material, and its main components are shown in Table 1.

[0036] Table 1: Main components of high iron zinc indium solution (g / L)

[0037] * indicates the unit is mg / L The steps for separating and recovering indium from the solution are as follows: (1) Extraction: The high-iron zinc-containing indium solution was fully mixed with a composite extractant DY23 composed of 20% bis(2,4,4-trimethylpentyl)phosphonic acid + 20% trioctyl phosphine oxide + 60% sulfonated kerosene in a ratio of 3:1 (volume ratio, the same below) for three-stage countercurrent extraction. The extraction temperature was room temperature (25°C), the extraction time was 1.5 min, and the oscillation intensity was 240rpm. After extraction, the zinc-containing raffinate and the indium-iron organic phase were separated. After testing, the indium content in the zinc-containing raffinate was 2.49 mg / L, the iron content was 27.46 g / L, the indium extraction rate reached 99.75%, the trivalent iron extraction rate was 8.93%, and the indium-iron separation coefficient β In / Fe3+ It is 4128.81.

[0038] (2) Washing: Add 200 g / L sulfuric acid as a detergent to the indium iron-containing organic phase (containing 484 mg / L zinc) obtained in step (1), with a volume ratio of O / A = 40:1, a washing time of 3 min, a washing temperature of 25°C, and an oscillation intensity of 240 rpm, and perform secondary countercurrent washing. After washing, a washing liquid and an indium iron-containing organic phase after impurity removal are separated. After testing, the zinc content in the washing liquid is 22.2 g / L, and the zinc washing rate reaches 99.5%.

[0039] (3) Indium removal: 4 mol / L hydrochloric acid was added as an indium removal agent to the indium-iron organic phase (containing 722 mg / L indium) obtained in step (2) after impurity removal. The indium-iron separation was performed in a seven-stage countercurrent indium removal process at a volume ratio of O / A = 20:1, a stripping time of 3 min, a washing temperature of 25°C, and an oscillation intensity of 240 rpm. After indium removal, an indium-containing stripping solution and an iron-containing organic phase were separated. After testing, the indium content in the indium-containing stripping solution was 56 g / L, the Fe content was 0.372 g / L, the indium content in the organic phase was 180 mg / L, the indium stripping rate was 94.12%, and iron was almost not stripped. The indium-iron separation effect was very obvious, and the remaining indium in the organic phase was almost not lost in the subsequent steps.

[0040] (4) Acid washing: pure water was added to the iron-containing organic phase obtained in step (3) as an acid washing agent, with a volume ratio of O / A = 5:1, a washing time of 3 min, and a washing temperature of 25°C, to perform a single-stage acid washing. + It was completely washed off, with indium loss less than 0.1%.

[0041] (5) Iron removal: Add 70 g / L oxalic acid solution as an iron removal agent to the washed organic phase obtained in step (4), and perform secondary countercurrent iron removal at a volume ratio of O / A = 2:1, an iron removal time of 13 min, and an iron removal temperature of 45°C to obtain an organic phase DY23 and an iron removal liquid. After testing, the iron content in the organic phase DY23 after iron removal is 83.1 mg / L, and the iron stripping rate reaches 98.18%. The organic phase DY23 can be returned to step (1) for re-extraction.

[0042] (6) Re-extraction: The organic phase DY23 obtained after de-ferrification was mixed with the high-iron indium solution at an O / A ratio of 1:3, with an extraction temperature of 25°C and an extraction time of 1.5 min, and a three-stage countercurrent extraction was performed. After testing, the indium content in the raffinate was 4.07 mg / L, the indium extraction rate reached 99.6%, and the indium-iron separation coefficient was β In / Fe3+ It is 2583.52.

[0043] The indium recovery rate of the whole process reaches 99.6%, the indium and iron separation effect is good, the extractant circulation effect is good, the raffinate and washing liquid can be returned to the subsequent zinc production process, the acid washing liquid can be added with acid and returned to the stripping section, and the anti-iron liquid can be used in the subsequent iron preparation process.

[0044] Example 2 A method for directly selectively extracting indium from a high-iron indium solution without reduction, the raw materials are the same as those in Example 1, and the steps of separating and recovering indium from the solution are as follows: (1) Extraction: The high-iron zinc-containing indium solution was mixed with a composite extractant DY23 composed of 30% 2-ethylhexyl phosphate mono-2-ethylhexyl ester + 20% tributyl phosphate + 50% sulfonated kerosene for four-stage countercurrent extraction, with a volume ratio of O / A = 1:3, an extraction temperature of 25°C, and an extraction time of 1.5 min. After testing, the indium content in the raffinate was 4.6 mg / L, the iron content in the indium-iron organic phase was 5.7 g / L, the indium extraction rate reached 99.54%, the trivalent iron extraction rate was 10.8%, and the indium-iron separation coefficient β In / Fe3+ It is 1806.04.

[0045] (2) Washing: Using 200 g / L sulfuric acid as a washing agent, the indium iron-containing organic phase produced in step (1) is subjected to secondary countercurrent washing at a volume ratio of O / A = 40:1, a washing time of 5 min, and a washing temperature of 25°C. After washing, a washing liquid and an indium iron-containing organic phase after impurity removal are separated.

[0046] (3) Indium stripping: 4 mol / L hydrochloric acid was used as an indium stripping agent to perform eight-stage countercurrent indium stripping on the indium-containing iron organic phase after impurity removal produced in step (2), with a volume ratio of O / A = 20:1, an indium stripping time of 5.71 min, and an indium stripping temperature of 25°C to obtain an indium-containing stripping solution and an iron-containing organic phase. After testing, the indium content in the indium-containing stripping solution was 20.3 mg / L, and the indium stripping rate reached 99.33%.

[0047] (4) Acid washing: Use pure water as the acid washing agent to perform secondary acid washing on the iron-containing organic phase produced in step (3), with a volume ratio of O / A = 10:1, an acid washing time of 2.99 min, and an acid washing temperature of 25°C. + It was completely washed off, with indium loss less than 0.1%.

[0048] (5) Iron removal: The washed organic phase produced in step (4) was subjected to single-stage iron removal using 70 g / L oxalic acid as an iron removal agent, with a volume ratio of O / A = 1:1, an iron removal time of 15 min, and an iron removal temperature of 45°C to obtain an organic phase DY23 and an iron removal liquid. After testing, the iron content in the iron removal liquid was 2.6 g / L, and the iron stripping rate reached more than 97%.

[0049] The indium recovery rate of the whole process reaches 99.54%, the indium-iron separation effect is good, the extractant circulation effect is good, the raffinate and washing liquid can be returned to the subsequent zinc production process, and the acid washing liquid can be added with acid and returned to the stripping stage.

[0050] Example 3 A method for selectively extracting indium from a high-iron indium solution without reduction, the experimental raw material is another batch of indium-containing solution, the main components are: indium concentration of 1.57g / L, iron concentration of 24.72g / L, divalent iron concentration of 10.28g / L, and trivalent iron concentration of 14.54g / L. This embodiment uses a centrifugal extractor for the experiment.

[0051] (1) Extraction: The high iron zinc indium solution and the composite extractant DY23 composed of 5% trialkyl phosphine oxide + 5% 2-ethylhexyl phosphate mono-2-ethylhexyl ester + 5% dimethyl heptyl methylphosphonate + 85% sulfonated kerosene were respectively introduced into a centrifugal extractor for five-stage countercurrent extraction. The extraction temperature was 25°C, the frequency of the centrifugal extractor was 70Hz, the mixing time was 1min, the water phase liquid inlet speed was 220ml / min, the oil phase liquid inlet speed was 110ml / min, the volume ratio O / A=2:1, and the hourly processing capacity was 13.2L / h. After testing, the indium content in the raffinate was 30.88mg / L, the iron content was 22.06g / L, the indium extraction rate reached 98.03%, and the trivalent iron extraction rate was 18.29%.

[0052] (2) Washing: Using 200 g / L sulfuric acid as a washing agent, the indium iron-containing organic phase produced in step (1) is subjected to secondary countercurrent washing at a volume ratio of O / A = 30:1, a washing time of 4 min, and a washing temperature of 25°C. After washing, a washing liquid and an indium iron-containing organic phase after impurity removal are separated.

[0053] (3) Indium stripping: Using 4 mol / L hydrochloric acid as the indium stripping agent, the indium-containing iron organic phase produced in step (2) after the impurities are removed is subjected to nine-stage countercurrent indium stripping, with a volume ratio of O / A = 25:1, an indium stripping time of 4 min, and an indium stripping temperature of 25°C to obtain an indium-containing stripping solution and an iron-containing organic phase. After testing, the indium content in the indium-containing stripping solution was 17.5 mg / L, and the indium stripping rate reached 99.51%.

[0054] (4) Acid washing: The iron-containing organic phase produced in step (3) was subjected to secondary acid washing using pure water as the acid washing agent, with a volume ratio of O / A = 15:1, an acid washing time of 4 min, and an acid washing temperature of 25°C. H+ in the organic phase was completely washed away, and the indium loss was less than 0.1%.

[0055] (5) Iron removal: The washed organic phase produced in step (4) was subjected to single-stage iron removal using 90 g / L oxalic acid as an iron removal agent, with a volume ratio of O / A = 2:1, an iron removal time of 10 min, and an iron removal temperature of 45°C to obtain an organic phase DY23 and an iron removal liquid. After testing, the iron content in the iron removal liquid was 2.8 g / L, and the iron stripping rate reached more than 96%.

[0056] During the whole process, the recovery rate of indium reaches 99.24%, the separation of indium and iron is thorough, the recycling effect of the extractant is good, the raffinate and washing liquid can be returned to the subsequent zinc production process, and the washing acid liquid can be added with acid and returned to the stripping stage.

[0057] Example 4 The difference from Example 1 is that the extraction time of the composite extractant is 4 min, and the other raw materials and steps are the same as those in Example 1.

[0058] After testing, when the extraction time is 4 minutes, the extraction rate of indium is 98.24%, and the extraction rate of iron is 22.15%. The extraction rate of indium is low, and the extraction rate of iron is high, and the efficient separation of indium and iron cannot be achieved.

[0059] Comparative Example 1 The difference from Example 1 is that the composition of the composite extractant is 40% di(2-ethylhexyl) phosphate + 60% sulfonated kerosene, and the remaining raw materials and steps are the same as those in Example 1.

[0060] Compared with DY23 extractant, the composite extractant composed of 40% di(2-ethylhexyl) phosphate + 60% sulfonated kerosene has a poorer extraction effect on indium, with an indium extraction rate of only 81.26% and an iron extraction rate of 32.94%. At the same time, the phase separation speed is slow, and a third phase will be generated. When using a centrifugal extractor for extraction, the problem of phase separation cannot be found at the oil outlet. This shows that single extractant A cannot achieve efficient separation of indium and iron.

[0061] Comparative Example 2 The difference from Example 1 is that the composition of the composite extractant is 40% trioctylphosphine oxide + 60% sulfonated kerosene, and the other raw materials and steps are the same as those in Example 1.

[0062] After testing, when 40% trioctylphosphine oxide + 60% sulfonated kerosene composite extractant was used to extract the high iron zinc indium solution, the indium extraction rate was 82.5%, and the iron extraction rate was as high as 91.25%. This shows that the single synergist B has poor selectivity for indium. At the same time, because the iron content in the solution is much higher than that of indium, the iron extraction rate is higher than that of indium, and the separation of indium and iron cannot be achieved.

[0063] Comparative Example 3 The difference from Example 1 is that the composition of the composite extractant is 50% bis(2,4,4-trimethylpentyl)phosphonic acid+10% trioctylphosphine oxide+40% sulfonated kerosene, and the other raw materials and steps are the same as those in Example 1.

[0064] After testing, when a composite extractant consisting of 50% bis(2,4,4-trimethylpentyl)phosphonic acid + 10% trioctyl phosphine oxide + 40% sulfonated kerosene was used to extract the high-iron-zinc indium solution, the indium extraction rate was 95.23% and the iron extraction rate was 26.58%, which failed to achieve efficient separation of indium and iron.

[0065] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for directly selectively extracting indium from a high-iron indium solution without reduction, characterized in that: The following steps are involved: S1. Mixing the high-iron zinc-containing indium solution obtained after acid leaching of zinc oxide with a composite extractant, extracting and separating to obtain an indium-containing iron organic phase; the high-iron zinc-containing indium solution is not subjected to reduction treatment, and the composite extractant is composed of 10% to 40% by volume of a phosphate extractant A, 5% to 20% of a phosphoric acid co-extractant B, and 40% to 85% of sulfonated kerosene; S2. Add a detergent to the indium-iron organic phase for washing, separate and obtain the indium-iron organic phase after zinc removal, then add a stripping agent to strip indium to obtain an indium-containing stripping solution, thereby achieving the separation of indium in the high-iron-zinc indium-containing solution.

2. The method for direct selective extraction of indium from a high-iron indium solution without reduction according to claim 1, characterized in that: In step S2, an iron-containing organic phase is obtained after back extraction, an acid washing agent is added to the iron-containing organic phase, and a washed organic phase is obtained after acid washing, and then an anti-iron agent is added to the washed organic phase, and an anti-iron liquid and an organic phase are obtained after back extraction. The anti-iron liquid is used for the preparation of iron, and the organic phase is a composite extractant, which is used for the extraction of the high-iron zinc-containing indium solution in step S1.

3. The method for direct selective extraction of indium from a high-iron indium solution without reduction according to claim 1, characterized in that: The phosphate extractant A is selected from one or more of 2-ethylhexyl phosphate mono-2-ethylhexyl ester, di(2-ethylhexyl) phosphate, bis(2,4,4-trimethylpentyl)phosphonic acid, and 1,3-dioctyl-2-thiourea.

4. The method for direct selective extraction of indium from a high-iron indium solution without reduction according to claim 1, characterized in that: The phosphoric acid synergist B is selected from one or more of trioctylphosphine oxide, tributyl phosphate, trialkylphosphine oxide, and dimethylheptyl methylphosphonate.

5. The method for direct selective extraction of indium from a high-iron indium solution without reduction according to claim 1, characterized in that: In step S1, the volume ratio of the high iron zinc indium-containing solution to the composite extractant is 1:1 to 3:

1.

6. The method for direct selective extraction of indium from a high-iron indium solution without reduction according to claim 1, characterized in that: In step S1, the extraction time is 1-3 min, and the extraction level is 2-5.

7. The method for direct selective extraction of indium from a high-iron indium solution without reduction according to claim 1, characterized in that: In step S2, the detergent is selected from one of sulfuric acid, hydrochloric acid or oxalic acid; the volume ratio of the detergent to the indium iron-containing organic phase is 20:1~50:1; the detergent concentration is 1~3 mol / L, the washing time is 1~5min, and the washing level is 1~4.

8. The method for direct selective extraction of indium from a high-iron indium solution without reduction according to claim 1, characterized in that: In step S2, the stripping agent is selected from one of sulfuric acid, hydrochloric acid or oxalic acid; the volume ratio of the stripping agent to the indium iron-containing organic phase is 10:1~30:1; the stripping agent concentration is 2~5 mol / L, the stripping time is 1~5 min; the stripping level is 5~10.

9. The method for direct selective extraction of indium from a high-iron indium solution without reduction according to claim 2, characterized in that: The acid washing agent is selected from pure water or tap water, and the volume ratio of the acid washing agent to the iron-containing organic phase is 5:1~15:1; the anti-iron agent is selected from one of sulfuric acid, hydrochloric acid or oxalic acid, the concentration of the anti-iron agent is 0.5~1.5 mol / L, the volume ratio of the anti-iron agent to the iron-containing organic phase is 1:1~3:1, and the temperature is 30~50°C.

10. The method for direct selective extraction of indium from a high-iron indium solution without reduction according to claim 1, characterized in that: In step S2, the obtained indium-containing stripping solution is adjusted to a pH of 2-4 by adding alkali to remove trace bismuth and iron in the solution, or is used as a stock solution for electrolyzing indium to prepare crude indium.

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