Method for efficiently recovering copper metal in white smoke dust leaching residues

Abstract

The invention relates to a method for efficiently recovering copper metal in white smoke dust leaching residues, and belongs to the field of comprehensive recovery of resources. Due to the fact that metal ions which are not completely washed remain on the surface of the leaching residues, Bi < 3 + >, Cu < 2 + >, Fe < 3 + > and the like are hydrolyzed and precipitated along with the increase of the pH value of the leaching residues in the flotation slurrying process, hydrophilic hydroxide and oxychloride covers are formed on the surface of copper sulfide, and CuS flotation is inhibited. According to the method, the leaching residues are washed with the HNO3 + NaCl solution, a sediment cover layer on the surface of the copper sulfide can be dissolved, the natural flotation property of the copper sulfide is recovered, and the efficiency of recovering the copper sulfide through flotation of the leaching residues is improved. The pretreatment technology before flotation has the advantages of being high in applicability, remarkable in effect and easy to implement on site, technological indexes can be optimized on the basis of an original flotation technology, the efficiency of separating copper and lead in the leaching residues is improved, useful minerals are prevented from being lost in tailings in the flotation circulation process, and optimization of the on-site flotation technology is achieved.

Description

Technical Field

[0001] The invention belongs to the field of mineral processing engineering application technology and comprehensive resource recovery, and specifically relates to a method for improving the separation efficiency of solid material particles in a mineral processing process. Background Art

[0002] White smoke is a product formed when volatile elements are easily volatilized by high temperature and airflow during smelting, and are carried away by the flue gas and condensed. There are three main processes for treating white smoke: pyrometallurgy, full wet method, and semi-wet method, which is a combination of wet method and pyrometallurgy. However, the smoke generated during the copper smelting process has a large variation in the content of metal elements due to the influence of smelting furnace type, smelting raw materials, process methods, and process conditions, so there is no unified treatment method for white smoke. At present, there is no universal and mature process flow for the separate treatment of white smoke in China. It contains a certain amount of valuable metal elements such as Cu, Zn, Bi, Cd, Au, Ag, etc., and is a potentially important secondary resource.

[0003] Flotation is the process of separating useful minerals from gangue minerals at the gas-liquid-solid interface based on the difference in hydrophilicity and hydrophobicity of the solid mineral surface. The target minerals are selectively adsorbed on the bubbles and float to the surface of the slurry with the bubbles, while the gangue minerals remain in the slurry. According to surveys, the use of flotation technology to treat ores in the world accounts for about 65% of the total processing volume. Because of its high separation efficiency and strong applicability, the flotation process can be applied to almost all types of minerals such as non-ferrous metals, rare metals, precious metals and non-metallic minerals. Flotation production usually consists of roughing operations, concentrating operations and scavenging operations. The target minerals enter the flotation concentrate after multiple stages of cyclic enrichment to achieve the purpose of separating and enriching useful minerals.

[0004] Leaching residue refers to the solid residue left after the valuable components of ore or other solid materials are leached with leaching agents. The composition of leaching residue depends on the leaching raw materials, leaching agents and leaching methods. Comprehensively recovering the useful components in leaching residue as much as possible has a positive effect on reducing its pollution to the environment, the occupation of land by leaching residue storage, and the comprehensive utilization of secondary resources.

[0005] The leached residue adopts flotation process instead of pressurization, and oxidative leaching is used to recover copper sulfide in the leached residue. In the process of washing and filtering the leached residue according to the leaching process, it is inevitable that metal ions remain on the surface of copper sulfide. As the pH value of the leached residue increases during the pulping process before flotation, the surface of copper sulfide is modified to inhibit flotation. The present invention uses nitric acid + sodium chloride solution to have good solubility for precipitated BiOCl, Fe(OH)3, and Cu(OH)3. Summary of the invention

[0006] The purpose of the present invention is to provide a pretreatment method for white smoke leaching residue before flotation, and to use the washing method provided by the present invention to solve the problem that the flotation recovery rate deteriorates due to the inevitable precipitation cover of ions during the flotation process of the leaching residue, thereby providing a new idea for the flotation recovery of valuable metals by leaching residue.

[0007] To achieve the above object, the present invention adopts the following technical solution: A method for efficiently recovering copper metal in white smoke leaching residue: using acid + chloride salt as a washing reagent for pre-treating the leaching residue, after washing and filtering, transferring the leaching residue to a flotation tank for flotation, and recovering the residual copper sulfide in the leaching residue.

[0008] Furthermore, the leached slag is obtained by leaching white smoke collected by a dust removal system in a copper smelting process with acid and chloride salt.

[0009] Furthermore, the acid in the washing agent is one of nitric acid, sulfuric acid, hydrochloric acid and phosphoric acid.

[0010] Furthermore, the chloride salt in the washing agent is one of sodium chloride, potassium chloride, magnesium chloride and calcium chloride.

[0011] Furthermore, the washing reagent is nitric acid+sodium chloride.

[0012] Furthermore, the preparation of the washing reagent includes: taking concentrated nitric acid, adding deionized water to dilute it, and then adding sodium chloride to mix evenly.

[0013] Further, the concentration of concentrated nitric acid is 68wt%.

[0014] Furthermore, the concentration of sodium chloride in the washing reagent is 0.5-2 mol / L.

[0015] Furthermore, the concentration of HNO3 in the washing reagent is 0.1-1 mol / L.

[0016] A method for efficiently recovering copper metal from white smoke leaching slag comprises the following steps: (1) Washing method: the leached residue is transferred to a stirring tank, a washing agent is added at a liquid-solid ratio of 1:1.25-2 g / ml, slurry washing is performed at a stirring speed of 100-400 r / min, the washing time is 10-15 min, and then solid-liquid separation is performed, and the leached residue is washed again 0-3 times according to the above method, and then deionized water is added at a liquid-solid ratio of 1:1-1.5 g / ml to wash the residual acid in the leached residue, and finally the washed residue is obtained by solid-liquid separation; (2) The washing residue obtained in step (1) is transferred to a flotation tank, a collector butyl xanthate and a frother 2# oil are added, and copper sulfide is recovered through one coarse, two fine and two sweep flotation.

[0017] The beneficial effects of the present invention are: (1) The Cu(OH)2, Fe(OH)3, BiOCl and other precipitates covered on the surface of copper sulfide in the present invention are easily dissolved in HNO3+NaCl solution, that is, washing has a modifying effect on the suppressed CuS surface, so that the suppressed CuS surface is restored from hydrophilic to hydrophobic, thereby improving the floatability of CuS particles.

[0018] (2) The present invention provides an efficient and convenient method for efficient separation and recovery of solid particles in hydrometallurgical leaching slag in the mineral processing process, including the cover inhibition of metal minerals in the leaching slag, washing and elimination inhibition rules, etc. It is convenient to explore the separation rules of useful metal minerals in the leaching slag, which is beneficial to the optimization of the flotation process. The optimization method is universal, the flotation raw material samples are diverse, and the leaching slag materials generated in the hydrometallurgical process can be processed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the overall process of treating the white smoke leaching slag of the present invention. Specific embodiments

[0020] A method for efficiently recovering copper metal in white smoke leaching residue comprises: mixing the leaching residue with a washing agent, and simultaneously vigorously stirring to promote the dissolution of metal precipitates on the surface of CuS, filtering after the reaction, and washing the residual acid in the leaching residue with deionized water after the filtration is completed, and then transferring the leaching residue to a flotation tank for flotation.

[0021] The specific steps include: (1) Take an appropriate amount of white smoke and leaching it with acid + chloride salt, and filter to obtain the leaching residue.

[0022] (2) Preparation of washing solution: Take concentrated nitric acid (analytical grade 68%) and add deionized water to dilute it to 0.1-1 mol / L. Then add NaCl (analytical grade 99%) with a final concentration of 0.5-2 mol / L to the dilute nitric acid solution. After mixing, place the mixture in a constant temperature water bath with a magnetic stirrer at 30-60°C and stir to dissolve.

[0023] (3) Transfer the leached residue sample from step (1) to a beaker, add the solution from step (2) at a liquid-to-solid ratio of 1 / 1.25-2 g / ml, stir at a constant speed of 100-400 r / min in a magnetic stirrer for 10 min, then filter and wash again 2-3 times according to the above method. After the last repeated washing, filter and use 1 / 1-1.5 g / ml deionized water to wash the residual acid in the leached residue; (4) The leached residue after pretreatment in step (3) is transferred to a flotation tank, 200 g / t of butyl xanthate collector and 50 g / t of 2# oil frother are added, and then subjected to one coarse, two fine and two scavenging flotation.

[0024] Furthermore, nitric acid can be replaced by sulfuric acid, hydrochloric acid, or phosphoric acid.

[0025] Furthermore, sodium chloride can be replaced by potassium chloride, magnesium chloride or calcium chloride.

[0026] The present invention provides a pretreatment method for hydrometallurgical leaching slag before flotation. In order to make the purpose, technical scheme and effect of the present invention clearer, the present invention is further described in detail below, but the present invention is not limited thereto.

[0027] Example 1: A method for pretreatment of leached residue before flotation, comprising the following steps.

[0028] The leached slag was obtained by leaching and filtering the white smoke dust from Fujian Zijin Copper Smelter after 183 g / L sulfuric acid + 200 g / L sodium chloride, liquid-to-solid ratio of 3 / 1 g / ml, and 90°C hot acid leaching.

[0029] Table 1. Test results of leached slag from Fujian Zijin Copper Smelter (unit: %) Without pretreatment: Before using the method of the present invention, the leached residue was filtered and directly transferred to the flotation tank, and 200 g / t of butyl xanthate as a collector and 50 g / t of 2# oil as a frother were added. The copper sulfide was recovered through one coarse, two fine and two sweep flotation. The test results are shown in the table below.

[0030] Table 2. Test results of leached residue without pretreatment (unit: %) Pretreatment: When using the method of the present invention, the leached residue is slurried and washed once with 0.1mol / L H2SO4+0.5mol / L NaCl solution, and the residual acid in the leached residue is washed with 1 / 1 g / ml deionized water while filtering after washing. The leached residue is washed with sulfuric acid+sodium chloride solution and then transferred to the flotation tank, where 200g / t of butyl xanthate collector and 50g / t of 2# oil frother are added, and copper sulfide is recovered through one coarse, two fine and two sweep flotation. The test results are shown in the table below.

[0031] Table 3. Results of leaching residue pretreatment test (unit: %) Example 2: A method for pretreatment of leaching residue before flotation, comprising the following steps.

[0032] The leached residue was obtained by leaching white smoke dust from the smelter of Jiangxi Xinke Environmental Protection Technology Co., Ltd. after filtering by hot acid leaching at 90°C with 183 g / L sulfuric acid + 200 g / L sodium chloride, liquid-to-solid ratio of 3 / 1 g / ml.

[0033] Table 4. Test results of leached slag from Jiangxi Xinke Environmental Protection Technology Co., Ltd. smelter (unit: %) Without pretreatment: Before using the method of the present invention, the leached residue was filtered and directly transferred to the flotation tank, and 200 g / t of butyl xanthate as a collector and 50 g / t of 2# oil as a frother were added. The copper sulfide was recovered through one coarse, two fine and two sweep flotation. The test results are shown in the table below.

[0034] Table 5. Test results of leached residue without pretreatment (unit: %) Method 2: When using the method of the present invention, the leached residue is washed once with a slurry using a 1mol / L H2SO4+2mol / L NaCl solution, and the residual acid in the leached residue is washed with 1 / 1 g / ml deionized water while being filtered after washing. The leached residue is washed with sulfuric acid+sodium chloride solution and then transferred to a flotation tank, where a collector butyl xanthate 200g / t and a foaming agent 2# oil 50g / t are added, and copper sulfide is recovered through one coarse, two fine and two sweep flotation. The test results are shown in the table below.

[0035] Table 6. Results of leaching residue pretreatment test (unit: %) Example 3: A method for pretreatment of leaching residue before flotation comprises the following steps.

[0036] The leached residue was obtained by leaching white smoke dust from the copper smelter of Anhui Tongling Nonferrous Metals Group after filtering through 183 g / L sulfuric acid + 200 g / L sodium chloride, liquid-to-solid ratio of 3 / 1 g / ml, and 90°C hot acid leaching.

[0037] Table 7. Test results of leached slag from Anhui Tongling Nonferrous Metals Group Copper Smelter (Unit: %) Without pretreatment: Before using the method of the present invention, the leached residue was filtered and directly transferred to the flotation tank, and 200 g / t of butyl xanthate as a collector and 50 g / t of 2# oil as a frother were added. The copper sulfide was recovered through one coarse, two fine and two sweep flotation. The test results are shown in the table below.

[0038] Table 8. Test results of leached residue without pretreatment (unit: %) Pretreatment: When using the method of the present invention, the leached residue is slurried and washed once with 0.5mol / L HNO3+1mol / L NaCl solution, and the residual acid in the leached residue is washed with 1 / 1 g / ml deionized water while filtering after washing. The leached residue is washed with sulfuric acid+sodium chloride solution and then transferred to the flotation tank, where 200g / t of butyl xanthate collector and 50g / t of 2# oil frother are added, and copper sulfide is recovered through one coarse, two fine and two sweep flotation. The test results are shown in the table below.

[0039] Table 9. Results of leaching residue pretreatment test (unit: %) Example 4: A method for pretreatment of leaching residue before flotation comprises the following steps.

[0040] The leached residue was obtained by filtering the white smoke dust from the copper smelter of Luoyang Copper Industry in Henan Province after being leached with 183 g / L sulfuric acid + 200 g / L sodium chloride, with a liquid-to-solid ratio of 3 / 1 g / ml and hot acid at 90°C.

[0041] Table 10. Analysis results of leached slag from Henan Luoyang Copper Smelter (unit: %) Without pretreatment: Before using the method of the present invention, the leached residue was filtered and directly transferred to the flotation tank, and 200 g / t of butyl xanthate as a collector and 50 g / t of 2# oil as a frother were added. The copper sulfide was recovered through one coarse, two fine and two sweep flotation. The test results are shown in the table below.

[0042] Table 11. Test results of leached residue without pretreatment (unit: %) Pretreatment: When using the method of the present invention, the leached residue is slurried and washed twice with 0.2mol / L HNO3+0.5mol / L NaCl solution, and the residual acid in the leached residue is washed with 1 / 1 g / ml deionized water while filtering after washing. The leached residue is washed with nitric acid+sodium chloride solution and then transferred to the flotation tank, where 200g / t of butyl xanthate collector and 50g / t of 2# oil frother are added. The copper sulfide is recovered through one coarse, two fine and two sweep flotation. The test results are shown in the table below.

[0043] Table 12. Results of leaching residue pretreatment test (unit: %) It can be concluded from the above examples that the pretreatment of leaching residue before flotation by the present invention not only greatly improves the flotation recovery efficiency, but also improves the concentrate grade, and the effect is obvious after the flotation process is optimized.

[0044] Detailed description of the present invention: (1) Leaching slag sample: The leaching slag used for flotation is the white smoke dust collected by the dust removal system in the copper smelting process. The smoke dust is leached with nitric acid + sodium chloride hot acid and then filtered. During the filtration, it is washed according to the leaching requirements.

[0045] (2) Preparation of washing solution: Take an appropriate volume of concentrated nitric acid (68% analytical grade) and add deionized water to dilute it to 0.1-1 mol / L. Then add NaCl (99% analytical grade) to the dilute nitric acid solution with a final concentration of 0.5-2 mol / L. After mixing, place the mixture in a constant temperature water bath with a magnetic stirrer at 30-60℃ and stir to dissolve.

[0046] (3) Washing process: transfer the leached residue sample to a beaker, add the solution of step (2) at a liquid-solid ratio of 1 / 1.25-2 g / ml, stir at a constant speed of 100-400 r / min in a magnetic stirrer for 10-15 min, then filter, and then return the filter residue to the beaker and wash it again 2-3 times according to the above method. Repeat the washing and finally filter, adding the solution of step (2) at a liquid-solid ratio of 1 / 0.5-1.5 g / ml as washing water for washing. After washing, use 1 / 1-1.5 g / ml deionized water to wash the residual acid in the leached residue; (4) Flotation process: The leached residue after washing and pretreatment is transferred to the flotation tank and slurried with deionized water. The pH of the leached residue slurry is in an acidic environment of 3-6, which meets the flotation conditions of copper sulfide. That is, there is no need to adjust the pH. The collector butyl xanthate and the frother 2# oil are added. After one coarse, two fine and two sweep flotation, copper sulfide is recovered.

[0047] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for efficiently recovering copper metal from white smoke leaching slag, characterized in that: Acid + chloride salt is used as a washing agent for pretreatment of the leaching residue. After washing and filtering, the leaching residue is transferred to a flotation tank for flotation to recover the residual copper sulfide in the leaching residue.

2. The method according to claim 1, characterized in that: The leached slag is obtained by leaching white smoke collected by a dust removal system in a copper smelting process with acid and chloride salt.

3. The method according to claim 1, characterized in that: The acid in the washing agent is one of nitric acid, sulfuric acid, hydrochloric acid and phosphoric acid.

4. The method according to claim 1, characterized in that: The chloride salt in the washing agent is one of sodium chloride, potassium chloride, magnesium chloride and calcium chloride.

5. The method according to claim 1, characterized in that: The washing reagent is nitric acid + sodium chloride.

6. The method according to claim 1, characterized in that: The preparation of the washing agent comprises: taking concentrated nitric acid, adding deionized water to dilute it, and then adding sodium chloride to mix evenly.

7. The method according to claim 6, characterized in that: The concentration of concentrated nitric acid is 68wt%.

8. The method according to claim 6, characterized in that: The concentration of sodium chloride in the washing reagent is 0.5-2 mol / L.

9. The method according to claim 6, characterized in that: The concentration of HNO3 in the washing reagent is 0.1-1 mol / L.

10. The method according to claim 1, characterized in that: The following steps are involved: (1) Washing method: the leached residue is transferred to a stirring tank, a washing agent is added at a liquid-solid ratio of 1:1.25-2 g / ml, slurry washing is performed at a stirring speed of 100-400 r / min, the washing time is 10-15 min, and then solid-liquid separation is performed, and the leached residue is washed again 0-3 times according to the above method, and then deionized water is added at a liquid-solid ratio of 1:1-1.5 g / ml to wash the residual acid in the leached residue, and finally the washed residue is obtained by solid-liquid separation; (2) The washing residue obtained in step (1) is transferred to a flotation tank, and a collector, butyl xanthate, and a frother, 2# oil, are added thereto. The copper sulfide is recovered by flotation through one coarse, two fine, and two sweeping flotations.

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