A process for efficiently recovering indium from alkali residue

Abstract

The present invention provides a treatment process for efficiently recovering indium from alkali slag, specifically comprising: S1, grinding and screening the alkali slag, and washing it with water to obtain a pretreated alkali slag; S2, placing the pretreated alkali slag into a reaction tank, adding an acid solution, and heating the reaction to obtain an acid leaching solution I; S3, adding the acid leaching solution to hydrogen peroxide for stirring and reacting, stopping the stirring, and allowing it to stand to obtain an acid leaching solution II; S4, adding water to the acid leaching solution II, followed by adding polyacrylamide for dispersion, filter pressing, and reducing with iron powder to obtain high-copper slag and acid leaching solution III; S5, purifying the acid leaching solution III through a reverse osmosis membrane and reducing it with zinc flakes to obtain sponge indium; S6, smelting the sponge indium to cast an indium ingot to obtain crude indium, and electrolytically refining the crude indium to obtain refined indium. The treatment process of the present invention achieves one-time recovery of indium, with a direct recovery rate of indium as high as 95% and a purity of 99.995%. At the same time, the direct recovery rate of copper reaches up to 85%, while all lead remains in the slag mud, achieving the separation of indium from other valuable metals, increasing economic benefits, and having good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and in particular to a processing technology for efficiently recovering indium from alkali slag. Background Art

[0002] In recent years, the national lead smelting industry has extensively researched technologies for recovering valuable metals from lead stirring. Among these, alkaline slag, also known as alkali slag or black slag, has attracted significant industry attention due to its rich content of copper (20%-30%), indium (1%-3%), and lead (30%-40%).

[0003] However, due to the granular nature of the alkali residue and the presence of metals, indium recovery is difficult, and the ideal recovery rate is difficult to achieve. Currently, repeated recovery (two to three times) is used, which can increase the indium recovery rate to around 85%. However, this recovery method is time-consuming and labor-intensive, with high production costs, and the overall recovery of valuable metals is poor.

[0004] Given the high indium content and considerable value in alkali slag, the tempering method is still used to re-refine the alkali slag. However, this method will cause the indium to disperse in the system and cannot be effectively recovered. At the same time, copper and lead will also be dispersed again, making it difficult to achieve comprehensive recovery of valuable metals. Summary of the Invention

[0005] In view of this, the present invention proposes a treatment process for efficiently recovering indium from alkaline slag. The treatment process is simple and efficient, can recover indium in one go, realizes the separation of indium from other valuable metals, and achieves comprehensive recovery of valuable metals, which has very great practical significance.

[0006] The technical solution of the present invention is achieved as follows:

[0007] A process for efficiently recovering indium from alkali slag comprises the following steps:

[0008] S1, grinding and sieving the alkali residue, and washing with water to obtain pretreated alkali residue;

[0009] S2, put the pretreated alkali residue in S1 into a reaction tank, add acid solution, heat to 70-90°C and react for 110-130 minutes to obtain acid leaching solution I;

[0010] S3, add hydrogen peroxide to the acid extract of S2, stir, react for 20-40 minutes, stop stirring, and let stand for 50-70 minutes to obtain acid extract II;

[0011] S4, adding water to the acid leaching solution II in S3, then adding polyacrylamide and dispersing for 8-12 minutes, filtering, and reducing the iron powder to obtain high copper slag and acid leaching solution III;

[0012] S5, purifying the acid leaching solution III in S4 through a reverse osmosis membrane and reducing it with zinc flakes to obtain sponge indium;

[0013] S6. Smelt the sponge indium in S5 to cast an indium ingot to obtain crude indium, and electrolytically refine the crude indium to obtain refined indium.

[0014] Furthermore, in step S1, the mesh size of the grinding and screening is 90-110 meshes.

[0015] Furthermore, in step S2, the solid-liquid ratio of the pretreated alkali residue to the acid solution is 1:8-12 g / mL; the acid solution is a sulfuric acid solution and a hydrochloric acid solution in a volume ratio of 1:2-4; and the concentration of the acid solution is 0.5-1.5 mol / L.

[0016] Furthermore, in step S3, the amount of hydrogen peroxide added is 1%-3% of the volume of the acid leaching solution, and the concentration is 30%-40% v / v; the stirring speed is 200-300 rpm.

[0017] Furthermore, in step S4, the ratio of the amount of water added to the amount of pretreated alkali residue added is 7-9:1 mL / g; the amount of polyacrylamide added is 0.05%-0.15% of the volume of the acid leaching solution II; and the mass ratio of the iron powder to the copper in the acid leaching solution II is 1.2-1.3:1.

[0018] Furthermore, in step S5, the membrane flux of the reverse osmosis membrane is 20-40 L / (m 2 ·h); the mass ratio of the zinc sheet to the indium in the acid leaching solution III is 1.2-1.3:1.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention's process for efficiently recovering indium from alkaline slag employs an "acid leaching-oxidation-flocculation-purification-reduction" process, enabling one-time recovery of indium. The process features clear operational steps, ease of implementation, and high production efficiency. The acid leaching process avoids the dispersion of indium in the system caused by the traditional tempering method for recovering indium, thereby improving the direct recovery rate of indium. Tests have demonstrated a direct recovery rate of up to 95% and a refined indium purity of 99.995%. Furthermore, the direct recovery rate for copper reaches a maximum of 85%, while all lead remains in the slag. The present process achieves separation of indium from other valuable metals, enhancing market added value and economic benefits, with promising application prospects. DETAILED DESCRIPTION

[0021] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0022] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0023] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0024] Example 1

[0025] A process for efficiently recovering indium from alkali slag comprises the following steps:

[0026] S1, grinding the alkali residue through a 100-mesh sieve, and washing with water to obtain pretreated alkali residue;

[0027] S2, the pretreated alkali residue in S1 is put into a reaction tank, and an acid solution with a concentration of 1.0 mol / L is added, the solid-liquid ratio of the pretreated alkali residue to the acid solution is 1:8-12 g / mL, wherein the acid solution is a sulfuric acid solution and a hydrochloric acid solution with a volume ratio of 1:3, and the temperature is raised to 80° C. and reacted for 120 min to obtain acid leaching solution I;

[0028] S3. Add 35% v / v hydrogen peroxide to the acid extract in S2 and stir at 250 rpm. The amount of hydrogen peroxide added is 2% of the volume of the acid extract. React for 30 minutes, stop stirring, and let stand for 60 minutes to obtain acid extract II.

[0029] S4, adding water to the acid leaching solution II in S3, the ratio of the amount of water added to the amount of pretreated alkaline slag added is 8:1 mL / g, then adding polyacrylamide, the amount of polyacrylamide added is 0.1% of the volume of the acid leaching solution II, dispersing for 10 minutes, filter pressing, and reducing iron powder. The mass ratio of iron powder to copper in the acid leaching solution II is 1.25:1, to obtain high-copper slag and acid leaching solution III;

[0030] S5, the acid leaching liquid III in S4 is passed through the membrane with a flux of 30L / (m 2 h) by reverse osmosis membrane purification, followed by reduction with zinc flakes, wherein the mass ratio of zinc flakes to indium in acid leaching solution III is 1.25:1, to obtain sponge indium;

[0031] S6. Smelt the sponge indium in S5 to cast an indium ingot to obtain crude indium, and electrolytically refine the crude indium to obtain refined indium.

[0032] The final purity of refined indium metal is 99.995%, the direct recovery rate of indium is 95%, and the direct recovery rate of copper is 85%.

[0033] Example 2

[0034] A process for efficiently recovering indium from alkali slag comprises the following steps:

[0035] S1, grinding the alkali residue through a 90-mesh sieve, washing with water to obtain pretreated alkali residue;

[0036] S2, the pretreated alkali residue in S1 was put into a reaction tank, and an acid solution with a concentration of 0.5 mol / L was added, the solid-liquid ratio of the pretreated alkali residue to the acid solution was 1:8 g / mL, wherein the acid solution was a sulfuric acid solution and a hydrochloric acid solution with a volume ratio of 1:2, and the temperature was raised to 70°C and reacted for 110 minutes to obtain acid leaching solution I;

[0037] S3. Add 30% v / v hydrogen peroxide to the acid extract in S2, stirring at 200 rpm. The amount of hydrogen peroxide added is 1% of the volume of the acid extract. React for 20 minutes, stop stirring, and let stand for 50 minutes to obtain acid extract II.

[0038] S4, adding water to the acid leaching solution II in S3, the ratio of the amount of water added to the amount of pretreated alkaline slag added is 7:1 mL / g, then adding polyacrylamide, the amount of polyacrylamide added is 0.05% of the volume of the acid leaching solution II, dispersing for 8 minutes, filter pressing, and reducing iron powder. The mass ratio of iron powder to copper in the acid leaching solution II is 1.2:1, to obtain high-copper slag and acid leaching solution III;

[0039] S5, the acid leaching liquid III in S4 is passed through the membrane with a flux of 20L / (m 2 h) by reverse osmosis membrane purification, followed by reduction with zinc flakes, wherein the mass ratio of zinc flakes to indium in acid leaching solution III is 1.2:1, to obtain sponge indium;

[0040] S6. Smelt the sponge indium in S5 to cast an indium ingot to obtain crude indium, and electrolytically refine the crude indium to obtain refined indium.

[0041] The final purity of refined indium metal is 99.993%, the direct recovery rate of indium is 93%, and the direct recovery rate of copper is 83%.

[0042] Example 3

[0043] A process for efficiently recovering indium from alkali slag comprises the following steps:

[0044] S1, grinding the alkali residue through a 110-mesh sieve and washing with water to obtain pretreated alkali residue;

[0045] S2, the pretreated alkali residue in S1 was put into a reaction tank, and an acid solution with a concentration of 1.5 mol / L was added, the solid-liquid ratio of the pretreated alkali residue to the acid solution was 1:12 g / mL, wherein the acid solution was a sulfuric acid solution and a hydrochloric acid solution with a volume ratio of 1:4, and the temperature was raised to 90° C. and reacted for 130 min to obtain acid leaching solution I;

[0046] S3. Add 40% v / v hydrogen peroxide to the acid extract in S2, stirring at 300 rpm. The amount of hydrogen peroxide added is 3% of the volume of the acid extract. React for 40 minutes, stop stirring, and let stand for 70 minutes to obtain acid extract II.

[0047] S4, adding water to the acid leaching solution II in S3, the ratio of the amount of water added to the amount of pretreated alkaline slag added is 9:1 mL / g, then adding polyacrylamide, the amount of polyacrylamide added is 0.15% of the volume of the acid leaching solution II, dispersing for 12 minutes, filter pressing, and reducing iron powder. The mass ratio of iron powder to copper in the acid leaching solution II is 1.3:1, to obtain high-copper slag and acid leaching solution III;

[0048] S5, the acid leaching liquid III in S4 is passed through the membrane with a flux of 40L / (m 2 h) by reverse osmosis membrane purification, followed by reduction with zinc flakes, wherein the mass ratio of zinc flakes to indium in acid leaching solution III is 1.3:1, to obtain sponge indium;

[0049] S6. Smelt the sponge indium in S5 to cast an indium ingot to obtain crude indium, and electrolytically refine the crude indium to obtain refined indium.

[0050] The final purity of refined indium metal is 99.994%, the direct recovery rate of indium is 94%, and the direct recovery rate of copper is 84%.

[0051] Comparative Example 1

[0052] The difference from Example 1 is that the traditional tempering method is used to extract and recover indium.

[0053] A process for efficiently recovering indium from alkali slag comprises the following steps:

[0054] S1. Place the alkali slag in a tempering furnace, raise the temperature to 700°C and maintain for 3 hours, take out the molten copper, cool it, and obtain a copper ingot;

[0055] S2, taking out the tempered alkali slag, cooling it, crushing it, adding lime as a flux and mixing it, with the mass ratio of lime to alkali slag being 1:3, placing the mixture in a tempering furnace, heating it to 1100° C. and holding it for 3 hours to obtain indium slag;

[0056] S3. Take out the indium slag, cool it, refine it, remove impurities, and obtain refined indium.

[0057] The final purity of refined indium metal was 89.999%, the recovery rate of indium was 82%, and the recovery rate of copper was 71%.

[0058] Comparative Example 2

[0059] The difference from Example 1 is that in step S5, reverse osmosis membrane purification is not used, and conventional filtration purification is used; the rest is consistent with Example 1.

[0060] A process for efficiently recovering indium from alkali slag comprises the following steps:

[0061] S1, grinding the alkali residue through a 100-mesh sieve, and washing with water to obtain pretreated alkali residue;

[0062] S2, the pretreated alkali residue in S1 is put into a reaction tank, and an acid solution with a concentration of 1.0 mol / L is added, the solid-liquid ratio of the pretreated alkali residue to the acid solution is 1:8-12 g / mL, wherein the acid solution is a sulfuric acid solution and a hydrochloric acid solution with a volume ratio of 1:3, and the temperature is raised to 80° C. and reacted for 120 min to obtain acid leaching solution I;

[0063] S3. Add 35% v / v hydrogen peroxide to the acid extract in S2 and stir at 250 rpm. The amount of hydrogen peroxide added is 2% of the volume of the acid extract. React for 30 minutes, stop stirring, and let stand for 60 minutes to obtain acid extract II.

[0064] S4, adding water to the acid leaching solution II in S3, the ratio of the amount of water added to the amount of pretreated alkaline slag added is 8:1 mL / g, then adding polyacrylamide, the amount of polyacrylamide added is 0.1% of the volume of the acid leaching solution II, dispersing for 10 minutes, filter pressing, and reducing iron powder. The mass ratio of iron powder to copper in the acid leaching solution II is 1.25:1, to obtain high-copper slag and acid leaching solution III;

[0065] S5, filtering the acid leaching solution III in S4, and reducing it with zinc flakes, wherein the mass ratio of the zinc flakes to the indium in the acid leaching solution III is 1.25:1, to obtain sponge indium;

[0066] S6. Smelt the sponge indium in S5 to cast an indium ingot to obtain crude indium, and electrolytically refine the crude indium to obtain refined indium.

[0067] The final purity of refined indium metal is 92.994%, the direct recovery rate of indium is 85%, and the direct recovery rate of copper is 85%.

[0068] The results show that in Comparative Example 1, which uses a traditional tempering method to extract and recover indium, the indium in this method disperses in the system, resulting in a reduced indium recovery rate and purity. This also reduces the copper recovery rate, which causes copper to disperse again, preventing comprehensive recovery of valuable metals. Compared with Comparative Example 2, the present invention uses a reverse osmosis membrane for purification, effectively removing impurities, improving the purity of sponge indium, and increasing the direct recovery rate and purity of indium, without affecting the direct recovery rate of copper.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A process for efficiently recovering indium from alkali slag, characterized in that: The following steps are involved: S1, grinding and sieving the alkali residue, and washing with water to obtain pretreated alkali residue; S2, the pretreated alkali residue in S1 is put into a reaction tank, and 0.5-1.5 mol / L of acid solution is added according to a solid-liquid ratio of 1:8-12 g / mL, the acid solution is a sulfuric acid solution and a hydrochloric acid solution in a volume ratio of 1:2-4, and the temperature is raised to 70-90 ° C. and the reaction is carried out for 110-130 minutes to obtain acid leaching solution I; S3. Add hydrogen peroxide to the acid extract of S2, the amount of hydrogen peroxide added is 1%-3% of the volume of the acid extract, the concentration is 30%-40% v / v, stir at 200-300 rpm, react for 20-40 minutes, stop stirring, and let it stand for 50-70 minutes to obtain acid extract II; S4, adding water to the acid leaching solution II in S3, and then adding polyacrylamide to disperse for 8-12 minutes, wherein the amount of polyacrylamide added is 0.05%-0.15% of the volume of the acid leaching solution II, filtering, and reducing the iron powder to obtain high-copper slag and acid leaching solution III; S5, the acid leaching liquid III in S4 is purified by reverse osmosis membrane, the membrane flux of reverse osmosis membrane is 20-40L / (m 2 h), reducing with zinc flakes to obtain sponge indium; S6. Smelt the sponge indium in S5 to cast an indium ingot to obtain crude indium, and electrolytically refine the crude indium to obtain refined indium.

2. A process for efficiently recovering indium from alkali slag according to claim 1, characterized in that: In step S1, the mesh size of the grinding and sieving is 90-110 meshes.

3. A process for efficiently recovering indium from alkali slag according to claim 1, characterized in that: In step S4, the ratio of the amount of water added to the amount of pretreated alkali residue added is 7-9:1 mL / g; the mass ratio of the iron powder to the copper in the acid leaching solution II is 1.2-1.3:

1.

4. A process for efficiently recovering indium from alkali slag according to claim 1, characterized in that: In step S5, the mass ratio of the zinc sheet to the indium in the acid leaching solution III is 1.2-1.3:1.