A method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement

Abstract

The present invention discloses a method for efficiently and greenly leaching zinc and indium from ultrasonically enhanced zinc oxide dust, and belongs to the technical field of hydrometallurgy. The present invention mixes the ground zinc oxide dust with a sulfuric acid solution, adds silicon dioxide particles, and performs enhanced leaching under ultrasonic conditions. After the leaching is completed, a leachate and a leaching residue containing silicon dioxide particles are obtained by solid-liquid separation, and zinc and indium in the zinc oxide dust enter the leachate, and the leaching residue containing silicon dioxide particles is dried and screened to obtain silicon dioxide particles. Compared with the traditional leaching treatment of adding an oxidant or oxygen pressure, the method of efficiently and greenly leaching zinc and indium from ultrasonically enhanced zinc oxide dust without adding an oxidant of the present invention does not require the addition of an oxidant, has a high extraction efficiency, and can be repeatedly recycled by adding silicon dioxide particles, which saves costs and does not produce excess waste residue. It is a green, safe, and efficient method for leaching zinc and indium, and has good industrial application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement. Background Art

[0002] Indium is a typical rare metal, which is widely used in high-tech and military fields such as indium tin oxide targets, electronic semiconductors, photovoltaic cells, etc. It is an important multi-purpose strategic resource. Indium has almost no independent deposits in nature. Due to its strong affinity with sulfur, it often coexists in non-ferrous metal sulfide ores such as lead, zinc and tin in an isomorphous form. At present, the raw materials for industrial production of primary indium mainly come from intermediate products or by-products in the metal smelting process, such as dust, leaching slag, slag, anode mud, electrolyte, etc. With the increase in indium consumption, recovering indium from metal smelting by-products has become an important source of indium.

[0003] As an important secondary resource containing zinc, zinc oxide dust has the main phases of ferrites such as ZnO, ZnS (sphalerite), ZnFe2O4 (zinc ferrite), PbSO4, and PbS. The indium-bearing phases are mainly indium oxide, indium sulfide, indium sulfate, and indium zinc ferrite, etc., which are important raw materials for recovering indium. Due to the presence of some ZnS and zinc ferrite in zinc oxide dust, part of the indium is still wrapped. In the sulfuric acid system, sphalerite is insoluble in water and sulfuric acid. It can only be partially leached by adding oxidants or using strengthening methods. This is one of the main reasons for the loss of indium and the low leaching rate in large-scale production. Most processes increase the leaching rate of Zn and In by adding chemical reagents and using auxiliary means, such as the atmospheric pressure-oxygen pressure combined leaching process. However, since the pressurized acid leaching needs to be carried out in an autoclave, it has high requirements for production equipment and is not suitable for industrial application; the room temperature oxidative acid leaching uses oxidants to achieve enhanced leaching. At present, the commonly used oxidants are KMnO4, MnO2, H2O2 and O3. KMnO4 is relatively expensive, which increases the leaching cost; adding pyrolusite (MnO2) as an oxidant to assist leaching will introduce more Mn, resulting in a decrease in current efficiency and an increase in slag volume; ozone and H2O2 are not only harmful to the health of operators, but their strong oxidation will seriously corrode the machine, resulting in increased maintenance costs. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement comprises the following steps:

[0007] (1) grinding zinc oxide dust to obtain fine-grained leaching raw materials;

[0008] (2) adding the ground zinc oxide dust to a sulfuric acid solution and mixing them uniformly, adding silicon dioxide particles, and then stirring and leaching under ultrasonic conditions. After completion, solid-liquid separation is performed to obtain a leachate and a leach residue containing silicon dioxide particles;

[0009] (3) After drying the leached residue containing silicon dioxide particles, the silicon dioxide particles are sieved out, and then washed with water 2 to 3 times and then dried to obtain silicon dioxide particles.

[0010] The invention recovers zinc and indium in the leaching solution and recovers lead in the leaching residue.

[0011] As a preferred embodiment of the present invention, in step (1), particles with a particle size of 120 mesh or more account for more than 95% of the fine-grained leaching raw materials.

[0012] As a preferred embodiment of the present invention, the mass volume ratio of the zinc oxide fume to the sulfuric acid solution is 1 g: (3-8) mL; and the concentration of the sulfuric acid solution is 1.5-4 mol / L.

[0013] As a preferred embodiment of the present invention, the mass volume ratio of the silicon dioxide particles to the sulfuric acid solution is (16-27) g:1 L; and the particle size of the silicon dioxide particles is 0.1 mm to 1.5 mm.

[0014] As a preferred embodiment of the present invention, the power of the ultrasound is 200-1200W, the temperature of the stirring leaching is 30-90°C, and the time is 30-120min.

[0015] As a preferred embodiment of the present invention, in the step (3), the drying temperature is 80 to 120° C. and the drying time is 60 to 120 min.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention mixes the ground zinc oxide dust and sulfuric acid solution evenly, adds silicon dioxide particles, and performs enhanced leaching under ultrasonic conditions. After the leaching is completed, a leachate and a leached residue containing silicon dioxide particles are obtained by solid-liquid separation. Zinc and indium in the zinc oxide dust enter the leachate, and the leached residue containing silicon dioxide particles is dried and sieved to obtain silicon dioxide particles, which can be used for subsequent recycling.

[0018] (2) Compared with the traditional leaching treatment of adding oxidants or oxygen pressure, the method of ultrasonically enhancing zinc oxide smoke to efficiently and greenly leaching zinc and indium without adding oxidants of the present invention does not require the addition of oxidants, has high extraction efficiency, and the addition of silicon dioxide particles can be repeatedly recycled, which saves costs and does not produce excess waste residue. It is a green, safe and efficient method for leaching zinc and indium, and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the process flow chart for efficient and green leaching of zinc and indium from zinc oxide dust enhanced by ultrasonic.

[0020] Figure 2 This is a diagram showing the leaching results of zinc and indium during the recycling process of silicon dioxide particles in Example 1. DETAILED DESCRIPTION

[0021] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0022] Example 1

[0023] A method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement, the specific steps are as follows:

[0024] (1) Zinc oxide dust grinding

[0025] The zinc oxide dust is ground to a particle size of more than 120 meshes, accounting for more than 90%, to obtain a fine-grained leaching raw material; first, 15g of zinc oxide dust is ground to a particle size less than 0.15mm, wherein the zinc content in the zinc oxide dust is 43wt%, and the indium content is 900g / t.

[0026] (2) Adding silica particles to enhance leaching

[0027] 15g of ground zinc oxide fume was added to 45ml of sulfuric acid solution with an initial concentration of 1.5mol / L at a temperature of 45°C. After the zinc oxide fume and the sulfuric acid solution were fully mixed, silicon dioxide particles with a particle size of 0.1mm and a mass of 0.9g were added for ultrasonic enhanced leaching. The leaching time was 30min, the temperature was 60°C, and the ultrasonic power was 200W.

[0028] (3) Separation of silica particles and leaching residue

[0029] After the reaction is completed, the zinc-rich and indium-rich leaching solution and the leaching residue containing silicon dioxide particles are obtained by solid-liquid separation. Zinc and indium in zinc oxide smoke enter the acid solution. The leaching residue containing silicon dioxide particles obtained by solid-liquid separation after leaching is washed 2 to 3 times with water, and after drying, the silicon dioxide particles are sieved out. The volume of the leaching solution is 54 ml, the weight of the leaching residue is 4.9 g, the zinc content in the residue is 5.44%, the zinc leaching rate is 95.86%, the indium content is 82.37 g / t, and the indium leaching rate is 97.01%.

[0030] The separated silica particles can be recycled and reused. Figure 2 It can be seen that the leaching rates of zinc and indium are still maintained above 95% and 97% respectively when the silicon dioxide particles are subjected to 12 times of ultrasonic enhancement of the zinc oxide smoke efficient green leaching process of zinc and indium.

[0031] Example 2

[0032] A method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement, the specific steps are as follows:

[0033] (1) Zinc oxide dust grinding

[0034] The zinc oxide dust is ground to a particle size of more than 120 meshes, accounting for more than 90%, to obtain a fine-grained leaching raw material; first, 15g of zinc oxide dust is ground to a particle size less than 0.20mm, wherein the zinc content in the zinc oxide dust is 43wt%, and the indium content is 900g / t.

[0035] (2) Adding silica particles to enhance leaching

[0036] 15g of ground zinc oxide fume was added to 80ml of sulfuric acid solution with an initial concentration of 2mol / L at a temperature of 70°C. After the zinc oxide fume and the sulfuric acid solution were fully mixed, 2.16g of silicon dioxide particles with a particle size of 1.5mm were added for ultrasonic enhanced leaching. The leaching time was 60min, the temperature was 90°C, and the ultrasonic power was 500W.

[0037] (3) Separation of silica particles and leaching residue

[0038] After the reaction is completed, the zinc-rich and indium-rich leaching solution and the leaching residue containing silicon dioxide particles are obtained by solid-liquid separation. Zinc and indium in zinc oxide smoke enter the acid solution. The leaching residue containing silicon dioxide particles obtained by solid-liquid separation after leaching is washed 2 to 3 times with water, and after drying, the silicon dioxide particles are sieved out. The volume of the leaching solution is 87 ml, the weight of the leaching residue is 4.1 g, the zinc content in the residue is 5.12%, the zinc leaching rate is 96.74%, the indium content is 77.71 g / t, and the indium leaching rate is 97.64%.

[0039] Example 3

[0040] A method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement, the specific steps are as follows:

[0041] (1) Zinc oxide dust grinding

[0042] The zinc oxide dust is ground to a particle size of more than 120 meshes, accounting for more than 90%, to obtain a fine-grained leaching raw material; first, 15g of zinc oxide dust is ground to a particle size less than 0.10mm, wherein the zinc content in the zinc oxide dust is 43wt%, and the indium content is 900g / t.

[0043] (2) Adding silica particles to enhance leaching

[0044] 15g of ground zinc oxide fume was added to 120ml of sulfuric acid solution with an initial concentration of 4mol / L at a temperature of 80°C. After the zinc oxide fume and the sulfuric acid solution were fully mixed, 2g of silicon dioxide particles with a particle size of 0.4mm and a mass were added for ultrasonic enhanced leaching. The leaching time was 120min, the temperature was 30°C, and the ultrasonic power was 1200W.

[0045] (3) Separation of silica particles and leaching residue

[0046] After the reaction is completed, the zinc-rich and indium-rich leaching solution and the leaching residue containing silicon dioxide particles are obtained by solid-liquid separation. Zinc and indium in zinc oxide smoke enter the acid solution. The leaching residue containing silicon dioxide particles obtained by solid-liquid separation after leaching is washed 2 to 3 times with water, and after drying, the silicon dioxide particles are sieved out. The volume of the leaching solution is 128 ml, the leaching residue weighs 3.1 g, the zinc content in the residue is 2.61%, the zinc leaching rate is 98.75%, the indium content is 55.74 g / t, and the indium leaching rate is 98.72%.

[0047] Comparative Example 1

[0048] A method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement, the specific steps are as follows:

[0049] (1) Zinc oxide dust grinding

[0050] The zinc oxide dust is ground to a particle size of more than 120 meshes, accounting for more than 90%, to obtain a fine-grained leaching raw material; first, 15g of zinc oxide dust is ground to a particle size less than 0.15mm, wherein the zinc content in the zinc oxide dust is 43wt%, and the indium content is 900g / t.

[0051] (2) Ultrasonic enhanced leaching

[0052] 15g of ground zinc oxide fume was added into 45ml of sulfuric acid solution with an initial concentration of 1.5mol / L at a temperature of 45°C. After the zinc oxide fume and the sulfuric acid solution were fully mixed, ultrasonic enhanced leaching was performed with a leaching time of 30min, a temperature of 60°C, and an ultrasonic power of 200W.

[0053] (3) Leaching and separation

[0054] After the reaction is completed, the zinc-rich and indium-rich leaching solution and leaching residue are obtained by solid-liquid separation. The zinc and indium in the zinc oxide smoke enter the acid solution. The leaching residue is washed with water 2 to 3 times and dried. The volume of the leaching solution is 60 ml, the leaching residue weighs 7.8 g, the zinc content in the residue is 7.35%, the zinc leaching rate is 91.10%, the indium content is 212.71 g / t, and the indium leaching rate is 87.71%.

[0055] According to the comparison between Example 1 and Comparative Example 1, it can be seen that without adding silica particles, ZnS (sphalerite), PbS, indium sulfide, etc. are difficult to dissolve. At the same time, ZnS and PbS wrap the indium-containing phase, which makes it difficult for the wrapped indium to react with acid. Therefore, after ultrasonic enhanced leaching, the leaching rate is significantly reduced.

[0056] Comparative Example 2

[0057] A method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement, the specific steps are as follows:

[0058] (1) Zinc oxide dust grinding

[0059] The zinc oxide dust is ground to a particle size of more than 120 meshes, accounting for more than 90%, to obtain a fine-grained leaching raw material; first, 15g of zinc oxide dust is ground to a particle size less than 0.10mm, wherein the zinc content in the zinc oxide dust is 43wt%, and the indium content is 900g / t.

[0060] (2) Adding silica particles without conventional ultrasonic leaching

[0061] 15g of ground zinc oxide fume was added to 120ml of sulfuric acid solution with an initial concentration of 4mol / L at a temperature of 80°C. After the zinc oxide fume and the sulfuric acid solution were fully mixed, 2g of silicon dioxide particles with a particle size of 0.4mm and a mass were added for conventional leaching. The leaching time was 120min and the temperature was 30°C.

[0062] (3) Separation of silica particles and leaching residue

[0063] After the reaction is completed, the zinc-rich and indium-rich leaching solution and the leaching residue containing silicon dioxide particles are obtained by solid-liquid separation. Zinc and indium in the zinc oxide smoke enter the acid solution. The leaching residue containing silicon dioxide particles obtained by solid-liquid separation after leaching is washed 2 to 3 times with water, and after drying, the silicon dioxide particles are sieved out. The volume of the leaching solution is 134 ml, the leaching residue weighs 8.1 g, the zinc content in the residue is 7.86%, the zinc leaching rate is 90.12%, the indium content is 124.33 g / t, and the indium leaching rate is 92.54%.

[0064] According to the comparison between Example 3 and Comparative Example 2, the mechanical, cavitation and micro-disturbance effects of ultrasound in the solution can produce local high temperature and high pressure and destroy inclusions such as PbSO4 and ZnFe2O4, thereby enhancing the mass transfer and heat transfer process. Therefore, under the condition of no ultrasonic enhanced leaching, the leaching rate is significantly reduced.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for efficiently and greenly leaching zinc and indium from zinc oxide dust by ultrasonic enhancement, characterized in that: The steps include: (1) Grinding the zinc oxide dust to a particle size of 120 mesh or more, accounting for more than 90%, to obtain a fine-grained leaching raw material; (2) adding the ground zinc oxide dust to a sulfuric acid solution and mixing them uniformly, adding silicon dioxide particles, and then stirring and leaching under ultrasonic conditions. After completion, solid-liquid separation is performed to obtain a leachate and a leach residue containing silicon dioxide particles; (3) After drying the leached residue containing silicon dioxide particles, the silicon dioxide particles are sieved out, and then washed with water 2 to 3 times and then dried to obtain silicon dioxide particles.

2. The method for efficient and green leaching of zinc and indium from zinc oxide dust by ultrasonic enhancement as claimed in claim 1, characterized in that: The mass volume ratio of the zinc oxide fume to the sulfuric acid solution is 1 g: (3-8) mL; the concentration of the sulfuric acid solution is 1.5-4 mol / L.

3. The method for efficient and green leaching of zinc and indium from zinc oxide dust by ultrasonic enhancement as claimed in claim 1, characterized in that: The mass volume ratio of the silicon dioxide particles to the sulfuric acid solution is (16-27) g:1 L; the particle size of the silicon dioxide particles is 0.1 mm to 1.5 mm.

4. The method for efficient and green leaching of zinc and indium from zinc oxide dust by ultrasonic enhancement as claimed in claim 1, characterized in that: The power of the ultrasound is 200-1200W, the temperature of the stirring leaching is 30-90°C, and the time is 30-120min.

5. The method for efficient and green leaching of zinc and indium from zinc oxide dust by ultrasonic enhancement as claimed in claim 1, characterized in that: In the step (3), the drying temperature is 80 to 120° C. and the drying time is 60 to 120 min.

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