CN101333605A - A technology for extracting indium from indium-rich bottom lead - Google Patents

Abstract

The invention relates to a technology for extracting indium from indium-rich bottom lead. Firstly, the indium-rich bottom lead is melted and cast into an anode plate, and a stainless steel plate or a refined lead plate is used as a cathode for electrolysis in a fluorosilicic acid system; The anode is electrolyzed and enters the electrolyte, and is precipitated at the cathode to obtain electric lead; indium is dissolved together with the lead and retained in the electrolyte, then P ₂₀₄ is used to extract indium from the electrolyte, and back-extracted with hydrochloric acid to obtain an indium-rich back-extraction solution , the indium-rich back-extraction solution adjusts the pH value and then replaces it with an aluminum plate to obtain sponge indium, and the sponge indium is processed by conventional pressing and caustic soda melting and casting to obtain crude indium. The present invention directly obtains electric lead products while effectively recovering indium, has high recovery rate of valuable metals, low reagent consumption, and low production cost; the process is closed loop, environment-friendly, and belongs to the clean production process.

Description

A technology for extracting indium from indium-rich bottom lead

【Technical field】

The invention belongs to the field of metallurgy and chemical industry, and relates to a technology for electrolyzing and extracting indium from indium-rich bottom lead.

【Background technique】

Explanation of name: P ₂₀₄ is di-(2-ethylhexyl) phosphoric acid . Indium, like other scattered elements, has no independent industrial deposits that can be mined. It mainly coexists with minerals such as lead, zinc, copper, and tin, and is the product of comprehensive utilization of resources. In the refining process of these main metals, the associated indium is enriched in different degrees in the products such as smoke dust, smelting waste slag (slag, leaching slag, purification slag, etc.), soot, and indium-containing waste according to different process conditions. Indium raw materials, and then various chemical metallurgical methods to prepare crude indium.

The indium associated with the zinc concentrate enters the crude zinc during the pyro-method zinc smelting process, and in the crude zinc rectification process, the indium and the lead enter the melting furnace of the lead tower together, and the bottom lead containing indium is obtained through melting; in addition, the lead containing Indium hard zinc also produces a kind of indium-rich bottom lead in the process of pyroprocessing; materials containing indium, lead fume, anode slime and other materials can also obtain indium-rich bottom lead in the process of pyro-smelting. The chemical composition of the indium-rich bottom lead is roughly (weight percent): In0.5-1.2%, Pb94-96%, Zn1-3%, Fe0.05-0.1%, As0.02%-0.1%. Indium mostly exists in the form of metal eutectic in the bottom lead, and it is very difficult to extract. For example, it is recorded in the article "Recovering Germanium and Indium from Electric Furnace Bottom Lead" in "Nonferrous Metals (Smelting Part)": In order to recover indium in bottom lead, it is generally based on the fact that indium and most impurity metals have a higher affinity to oxygen than lead The principle is to blast and oxidize the molten crude lead solution, so that indium and other impurity metals are preferentially oxidized into the scum, and the crude lead is electrolytically refined. After the scum is washed with water to remove the alkali, the inorganic acid is used as the leaching agent to make the In ₂ O ₃ in the scum react with it to form In ₂ (SO ₄ ) ₃ into the solution; a large amount of PbO will form insoluble PbSO ₄ to precipitate , and separated from indium, and then filtered the resulting leachate, then through the conventional "aluminum plate replacement - compaction alkali fusion" treatment process to obtain crude indium. Although this process can achieve better recovery of indium, it also has the disadvantage of a long process. The direct recovery rate of indium is only about 70-75%, and the total recovery rate is only about 85%. In the oxidative slagging process, the slagging temperature and blast pressure are 800-900°C and 0.15-0.24MPa respectively. The power consumption and energy consumption are large, and a large amount of expensive caustic soda is also consumed, and the working conditions are harsh. The scum is leached with sulfuric acid, and the leaching rate of indium is only about 85%. If HCl+H ₂ SO ₄ mixed acid is used for leaching, and KMnO ₄ oxidant is added, the leaching rate of indium can be increased to more than 90%, but the production cost will also increase significantly. ; In addition, due to the low concentration of indium in the leaching solution and the elution of alkali from the scum, the discharge of waste water during the entire process is large and the environmental pollution is serious.

【Content of invention】

In order to overcome the above-mentioned shortcomings of the prior art, the present invention provides a technology for extracting indium from indium-rich bottom lead with short process, low production cost, high recovery rate of valuable metals, and environmental friendliness. The present invention effectively recovers indium while , but also directly obtain high-grade electric lead.

The technical solution adopted by the present invention to solve its technical problems is: a technology for extracting indium from indium-rich bottom lead, including bottom lead electrolysis and electrolyte extraction of indium, melting and casting the indium-rich bottom lead into an anode plate, and using stainless steel The plate or refined lead plate is used as the cathode, and the electrolysis is carried out in an acidic aqueous solution containing fluorine. The electrolysis process conditions are: current density 140-200A/m ² , electrolysis cycle 24-92h, electrolyte circulation 0-1500L/h , the electrolysis temperature is 25～60℃, the pole distance is 4～12cm, the pre-electrolysis solution contains In≤2.0g/L, the electrolysis additives added to each ton of electric lead are: bone glue 0.4～0.5kg, sodium lignosulfonate 0.25～ 0.45kg; Indium is electrodissolved from the anode and enriched in the electrolyte, and lead is deposited at the cathode to form electric lead; then P ₂₀₄ is used to extract indium from the electrolyte, and the process conditions for extracting indium are: the weight percent content of the organic phase is 30 %P ₂₀₄ + 70% sulfonated kerosene, the extraction stages are 2-4, compared to V _O : _VA = 1 (3-5); and back-extracted with hydrochloric acid to obtain an indium-rich stripping solution, the stripping condition is: hydrochloric acid The concentration is 4-7mol·L ^-1 , compared with V _O : _VA = (4-6): 1, the series is 3-5, and the indium-rich back-extraction solution is first adjusted to pH = 1.0-4.0 with lye. Then replace the aluminum plate at 5-60°C to obtain indium sponge.

The indium-rich bottom lead refers to the bottom lead of the rectification tower refined by the crude zinc fire method, or the bottom lead treated by the hard zinc fire method, or the indium-rich bottom lead obtained by fire smelting of materials containing indium and lead, and its chemical composition The weight percent content is: In0.3-1.2, Pb85.2-98.5, Zn0.5-2.5, Sb0.32-0.85, Sn0.5-1.5.

The fluorine-containing acidic aqueous solution is lead fluorosilicate solution, and its composition is (g·L ^-1 ): H ₂ SiF ₆ 190-231, Pb60-110, In≤2.0, Sn≤1.26.

The beneficial effects of the present invention are: the technological process is short, the recovery rate of valuable metals is high, the consumption of reagents is small, the production cost is low, the process is closed loop, the environment is friendly, and it belongs to the clean production process. lead products.

【Description of drawings】

Fig. 1 is a schematic block diagram of the process flow of the present invention.

【Detailed ways】

Below in conjunction with embodiment the present invention is further described.

A technology for extracting indium from indium-rich bottom lead, including bottom lead electrolysis and electrolyte extraction of indium, see Figure 1, the raw material is indium-rich bottom lead, and the indium-rich bottom lead refers to the bottom of B# tower refined by crude zinc fire method Lead, or hard zinc fire-treated bottom lead, or indium-rich bottom lead obtained by fire smelting materials containing indium and lead, B # tower (B tower) is a rectification tower in crude zinc distillation and refining. Crude zinc is heated and condensed at high temperature in the lead tower, and the metals with low boiling point in the crude zinc become vapor to separate from the metals with high boiling point. The zinc that has not evaporated in the lead tower but contains more high boiling point metals flows into the melting furnace from the lower part of the lead tower , the melt is divided into three layers, the uppermost layer is lead-containing zinc, also known as cadmium-free zinc or B-number zinc, and then B# number zinc is added to B# tower for rectification to realize the separation of zinc from high-boiling point metals such as lead, indium, and iron , The crude lead produced at the bottom of tower B is also called bottom lead. The weight percentage content of its chemical composition is: In0.3～1.2, Pb85.2～98.5, Zn0.5～2.5, Sb0.32～0.85, Sn0.5～1.5; first melt the indium-rich bottom lead and cast it into an anode Plate, with stainless steel plate or refined lead plate as the cathode, electrolyze in a fluorine-containing acidic aqueous solution, the fluorine-containing acidic aqueous solution is lead fluorosilicate solution, and its composition is (g·L ^-1 ): H ₂ SiF ₆ 190～231, Pb60～110, In≤2.0, Sn≤1.26; electrolysis process conditions are: current density 140～200A/m ² , electrolysis cycle 24～92h, electrolyte circulation 0～1500L/h, electrolysis The temperature is 25-60°C, the pole distance is 4-12cm, the pre-electrolysis solution contains In≤2.0g/L, and the electrolysis additives added to each ton of electric lead are: bone glue 0.4-0.5kg, sodium lignosulfonate 0.25-0.45kg ; Indium is electrodissolved from the anode and enriched in the electrolyte, and lead is deposited into electric lead at the cathode; then P ₂₀₄ is used to extract indium from the electrolyte, and the process conditions for extracting indium are: the weight percentage of the organic phase is composed of 30% P ₂₀₄ +70% sulfonated kerosene, the extraction stages are 2-4, compared with V _O : _VA = 1 (3-5); and back-extracted with hydrochloric acid to obtain an indium-rich stripping solution, the stripping condition is: hydrochloric acid concentration 4 ～7mol·L ^-1 , compared with V _O : _VA =(4～6):1, and the series is 3～5, the indium-rich stripping solution is first adjusted to pH = 1.0～4.0 with lye, and then Replace aluminum plates at 5-60°C to obtain indium sponge. The invention has the advantages of short technological process, high recovery rate of valuable metals, small consumption of reagents, low production cost, closed circuit circulation of the process, environmental friendliness, clean production process, and direct production of electric lead products while effectively recovering indium.

Example 1:

1. The chemical composition is (%): In: 0.357, Pb: 88.89, Zn: 8.75, Cu: 0.006, Fe: 0.0023, As: 0.023, Sb: 0.32, Ge: 0.021, Sn: 0.8, Ag<0.0005 Indium-rich lead was melted and cast into an anode plate of length×width=20cm×12cm.

2. Using a stainless steel plate as the cathode, conduct bottom lead electrolysis in a lead fluorosilicate solution with chemical composition (g/L): Pb ²⁺ : 83.46, SiF ₆ ^2- : 196.54, In ³⁺ : 1.91. Before electrolysis The electrolysis process conditions of the solution are: current density 155A·m ^-2 , electrolysis period 24h, electrolyte circulation volume 100mL·h ^-1 , temperature 25°C, pole distance 40mm, electrolysis additives: bone glue 0.5kg/t, _{electric lead} , wood Sodium sulfonate 0.45kg/t _{electric lead} . The anode consumes 276.15g, precipitates 285.05g of electric lead containing Pb98.31%, and produces 2.32g of anode slime. Its chemical composition and composition are (%): Pb: 7.73, In: 0.263. The electrolysis rate of indium in the whole electrolysis process is 91%, and the lead precipitation rate and current efficiency are both >98%. The chemical composition of the solution after electrolysis is (g/L): Pb ²⁺ : 76.87, SiF ₆ ^2- : 208.11, In ³⁺ : 2.33.

3. Extract indium from the above electrolyzed liquid with P ₂₀₄ and back-extract indium with hydrochloric acid. The operating conditions are: ①The organic phase is composed of P ₂₀₄ and sulfonated kerosene in a volume ratio of 3:7, ②The number of extraction stages is 3, V _O : _VA = 1:3, ③ the loaded organic phase was washed with 200g L ^-1 fluorosilicic acid, V _O : _VA = 1: 1, the order was 4, ④ the organic phase was washed with 6mol L ^-1 hydrochloric acid Back extraction, V _O : _VA = 3: 1, the number of stages is 3, ⑤ The temperature is 25°C, and the shaking and standing time are both 5 minutes. The contents of indium in the raffinate and stripping solution are 0.00008g/L and 9.236g/L respectively, and the concentrations of Pb and Zn in the raffinate are trace amounts; the extraction rate and stripping rate of indium are both > 96%.

Example 2:

1 Melt the indium-rich bottom lead with the chemical composition (%): In: 0.888, Pb: 97.33, Zn: 0.98, Cu<0.001, Fe: 0.0026, Sb: 0.44, Ge: 0.018, Sn: 1.19, Ag: 0.00013 And cast the anode plate of length×width=12.5cm×7.2cm.

2. Using the stainless steel plate as the cathode, carry out three cycles in the lead fluorosilicate solution with chemical composition (g/L): Pb ²⁺ 93.27～103.87, SiF ₆ ^2- 196.54～230.40, In ³⁺ 1.436～1.592 Periodic "bottom lead electrolysis - electrolyte P ₂₀₄ extraction of indium - hydrochloric acid back extraction of indium" operation. The electrolysis process conditions are: current density 155A·m ^-2 , electrolysis cycle 24h, electrolyte circulation volume 100mL·h ^-1 , temperature at room temperature, pole distance 40mm, electrolysis additives: bone glue 0.5kg/t _{electrolytic lead} , sodium lignosulfonate 0.45kg/t _{electric lead} . The whole process consumes 460.65g of anodes and produces 475.65g of lead containing Pb98.42%. The output of anode slime is 6.35g, and its chemical composition is (%): Pb9.30, In0.37, Ag0.05; indium electrolysis rate is 99.28%, lead precipitation rate and current efficiency are 91.43% and 96.82% respectively. The chemical composition of the solution after electrolysis is (g/L): Pb ²⁺ 99.82, SiF ₆ ^2- 229.58, In ³⁺ 2.23.

3. Indium extraction conditions in Example 1, a total of 6.28L of the above electrolyzed solution was used to extract indium with P ₂₀₄ and back-extract indium with hydrochloric acid. The organic phase used for indium is regenerated from the organic phase obtained in the stripping process of the previous cycle. The average contents of indium in the raffinate and stripping solution are 0.064g/L and 32.78g/L respectively. The extraction rate of indium And stripping rate> 95%.

4. Regeneration of the organic phase, using 7% oxalic acid solution to regenerate the organic phase, the process conditions are: V _O : _VA = 4: 1, the number of stages is 4, the temperature is 30°C, and the shaking and standing time are both 5 minutes .

Example 3:

1. The average chemical composition is (%): In0.31, Pb97.33, Zn1.81, Sb0.31, Sn0.62 indium-rich bottom lead is melted and cast into an anode plate

2. Using refined lead as the cathode, indium-rich bottom lead electrolysis is carried out in a lead fluorosilicate solution with chemical composition (g/L): Pb ²⁺ 106.01, SiF ₆ ^2- 194.33, In ³⁺ 0.069, Sn1.16 . The electrolysis process conditions are: current density 193.82A/m ² , homopolar center distance 90mm, electrolyte temperature 41-43°C, electrolyte circulation speed 15-25L/min, cathode-anode cycle 3d, electrolytic additive is bone glue 0.4kg/t _{Electric lead} , sodium lignosulfonate 0.25kg/t _{electric lead} . The electrolysis process consumed a total of 74.95t of anodes, and produced 74.53t of lead containing Pb99.99%. The indium electrolysis rate was 95.53%, and the lead precipitation rate and current efficiency were 96.35% and 89.45%, respectively. The chemical composition of the solution after electrolysis is (g/L): Pb ²⁺ 16.66, SiF ₆ ^2- 233.33, In ³⁺ 4.99

3. Take more than 1m ³ of indium after electrolysis, the main technical conditions are as follows: (1) P ₂₀₄ extraction, organic phase composition 30% P ₂₀₄ +70% kerosene, compared V _O : V _A =1:2, extraction The number of stages is 4, the flow rate of the stock solution is 40mL/s, and the flow rate of the organic phase is 20mL/s; (2) the extraction phase is washed, the concentration of the fluorosilicic acid washing solution is 200g/L, the flow rate is 10mL/s, and the washing ratio V _O : V _A =2 : 1. The number of washing stages is 4. The composition of the fluoric acid washing liquid is (g/L): In0.45, Sn0.04, Sb0.023; (3) Hydrochloric acid stripping, the concentration of hydrochloric acid is 6mol·L ^-1 Ratio V _O : _VA = 3: 1, the number of stripping stages is 4, the flow rate of stripping indium solution is 6mL/s, and the raffinate composition (g/L): In0.0012, Sn0.57, Sb0.18; The extract solution contains In41.12g/L; (5) The back-extraction solution is regenerated with 5% oxalic acid solution, the flow rate of the oxalic acid solution is 10mL/s, and the composition (g/L) of the oxalic acid regeneration solution: In0.000068, Sn0.012, Sb0.045. The extraction rate and stripping rate of indium are both >98%;

4. Add lye to the indium-rich back-extraction solution to adjust the pH value to 2.0, and replace it with a conventional aluminum plate at 45° C. to prepare sponge indium. Then, the sponge indium is pressed into a ball and cast with caustic soda to obtain a crude indium product, and its composition is ( %): In97.53, Sn0.11, Pb1.7, Cd0.0069. The aluminum plate replacement rate is 99.24%.

Claims (3)

1, a kind of technology of from indium-rich bottom lead, extracting indium, comprise that plumbous electrolysis in the end and electrolytic solution carries indium, it is characterized in that: with indium-rich bottom lead fusion and be cast into positive plate, with stainless steel plate or lead bullion plate is negative electrode, carry out electrolysis in a kind of fluorine-containing acidic aqueous solution, electrolytic processing condition are: current density 140～200A/m ², electrolysing period 24～92h, circulation of elecrolyte amount 0～1500L/h, electrolysis temperature is 25～60 ℃, pole span 4～12cm contains In≤2.0g/L in the liquid before the electrolysis, and the electrolysis additive that adds in the electric lead per ton is: gelatine 0.4～0.5kg, the 0.25～0.45kg of wooden sodium sulfonate; Indium is molten and be enriched in electrolytic solution from anode electricity, plumbously becomes electricity plumbous in cathodic deposition; Use P again ₂₀₄Extraction of indium from electrolytic solution, the processing condition of collection indium are: it is 30%P that the weight percent content of organic phase is formed ₂₀₄+ 70% sulfonated kerosene, 2～4 grades of extraction progression are compared V ₀: V _A=1 (3～5); And obtaining rich indium strip liquor with the hydrochloric acid back extraction, the back extraction condition is: concentration of hydrochloric acid 4～7molL ^-1, compare V ₀: V _A=(4～6): 1, progression is 3～5 grades, and rich indium strip liquor is regulated pH value=1.0～4.0 with alkali lye earlier, carries out the aluminium sheet displacement at 5～60 ℃ again and obtains the sponge indium.

2, the technology of from indium-rich bottom lead, extracting indium as claimed in claim 1, it is characterized in that: described indium-rich bottom lead is meant the end lead of lead at the bottom of the rectifying tower of crude zinc pyrorefining or hard zinc pyrogenic attack or contains indium, the resultant indium-rich bottom lead of lead materials pyrometallurgical smelting that the weight percent content of its chemical ingredients is: In 0.3～1.2, Pb 85.2～98.5, Zn 0.5～2.5, Sb 0.32～0.85, Sn 0.5～1.5.

3, the technology of from indium-rich bottom lead, extracting indium as claimed in claim 1, it is characterized in that: described fluorine-containing acidic aqueous solution is a plumbous silicofluoride solution, its composition is (gL ^-1): H ₂SiF ₆190～231, Pb60～110, In≤2.0, Sn≤1.26.

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