A method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalyst

Abstract

The present invention discloses a method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts, and belongs to the technical field of comprehensive recovery of precious metals. The method comprises the following steps: uniformly mixing silver-containing copper slag, spent automobile catalysts and auxiliary materials to obtain mixed slag; smelting the mixed slag to obtain molten slag and multi-metal alloy products; vacuum distilling the multi-metal alloy to obtain base metal volatiles and rich precious metal residues; the auxiliary materials are one or more of coke, charcoal, activated carbon, flour, sodium borate, borax, sodium carbonate, silicon dioxide, quicklime or calcium carbonate. The present invention is based on multi-metal smelting capture and vacuum distillation to achieve comprehensive recovery of valuable elements in two secondary resources, especially efficient enrichment of silver, gold and platinum group metals, enriching platinum group metals in refractory cordierite-type carrier catalysts into silver-copper alloys, providing convenience for subsequent precious metal refining, shortening the precious metal refining process, and being efficient and environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive recovery of precious metals, and in particular relates to a method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts. Background Art

[0002] Platinum group metals platinum, palladium and rhodium are widely used in electronic appliances, industrial catalysis and medical fields. They are important strategic resources that cannot be replaced by national defense, modern industry and high-tech industries. my country consumes a huge amount of platinum group metals, but its mineral resources are scarce. Automobile exhaust purification catalysts (referred to as "autocatalysts") are the largest industrial application field of platinum group metals. 6% to 8% of platinum, 75% of palladium and almost all rhodium in my country are used in the manufacture of autocatalysts. With the failure and scrapping of catalysts, more than 20,000 tons of waste autocatalysts will be generated each year, and the amount of platinum group metal resources is huge. At present, molten copper, iron, matte (heavy metal sulfide eutectic) and other materials are mainly used to capture platinum, palladium and rhodium in waste autocatalysts, and then chemical means such as oxidation blowing, electrolysis and wet leaching are used to enrich and refine platinum, palladium and rhodium in the captured materials. The existing process separates platinum group metals from the capture agent, and 90% of the capture agent is oxidized or dissolved and separated, which has prominent problems such as long processing cycle, low efficiency, high material consumption and high environmental pressure. Therefore, actively exploring and researching green recovery technologies for platinum, palladium and rhodium in waste automobile catalysts has important practical significance for achieving green disposal of hazardous waste in my country and alleviating the shortage of platinum group metal resources.

[0003] The high-silver copper slag produced in the lead-copper smelting system is a high-value-added secondary resource produced by the lead-copper anode mud smelting system. Open-circuit and efficient recovery of valuable metals in high-silver copper slag is an important basis for the rational use of resources. High-silver copper slag contains 10-30% Ag, 10-5000g / t Au, 10-40% Cu, 5-30% Pb, 1-10% Sb, and 1-15% Bi. Copper slag is a common slag produced by a smelting system. Different recovery methods will be used due to its different component contents. Currently, the commonly used methods include the recycle process, the pyrometallurgical depletion method, and the ore dressing enrichment method. At present, smelting enterprises often use the recycle process to recover precious metals such as silver and gold, or store them, but this results in the dispersion of silver and gold, low direct recovery rate of precious metals, and the accumulation of lead, copper, antimony and bismuth in the system and the inability to effectively open the furnace for recovery. Pyrometallurgical enrichment is the simplest and most direct method to recover valuable metal elements in copper slag. This method is based on carbon thermal reduction to enrich the metal and part of the iron in the copper slag in an iron-rich alloy. Common processes include reduction matte smelting and return remelting. However, pyrometallurgical enrichment is generally suitable for copper slag with high copper and iron content, and silver cannot be recovered in an open circuit. Another method is wet leaching of copper slag, the principle of which is mainly to control pH. Copper enters the solution in an ionic state and is usually recovered as copper sulfate. Silver and other precious metals enter the leached slag, and silver and other precious metals still need to be further recovered. The principle of mineral processing and enrichment methods is to use various methods to separate the dissociated minerals as much as possible and enrich the useful minerals according to the different physical and chemical properties of different minerals. Common methods include flotation, magnetic separation, electrostatic separation and gravity separation, but the conductivity of various minerals in copper slag is not much different, and the occurrence particle size is too fine, so electrostatic separation is not suitable for processing most copper slag.

[0004] Therefore, in order to achieve the comprehensive utilization of valuable metals in spent automotive catalysts and high-silver copper slag, the development of common synergistic recovery technology is the key to the recycling of precious metal resources. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts comprises the following steps:

[0008] (1) uniformly mixing silver-containing copper slag, spent automobile catalyst and auxiliary materials to obtain a mixed slag material;

[0009] (2) smelting the mixed slag to obtain slag and a multi-metal alloy product;

[0010] (3) vacuum distilling the multi-metal alloy to obtain base metal volatiles and noble metal residues;

[0011] The auxiliary material is one or more of coke, charcoal, activated carbon, flour, sodium borate, borax, sodium carbonate, silicon dioxide, quicklime or calcium carbonate.

[0012] As a preferred embodiment of the present invention, the mass ratio of the silver-containing copper slag, the spent automobile catalyst, and the auxiliary material is 0.5-1:0.5-1:0.1-0.3.

[0013] As a preferred embodiment of the present invention, the silver-containing copper slag is an intermediate by-product of non-ferrous metal smelting or secondary resource recovery, and its composition and content include Ag 10-30%, Au 10-5000g / t, Cu 10-40%, Pb 5-30%, Sb1-10%, Bi 1-15%, and the remainder is other impurities.

[0014] As a preferred embodiment of the present invention, the spent automobile catalyst is cordierite-type spent automobile purifier powder.

[0015] The bluestone type automobile failure purifier powder is honeycomb-shaped.

[0016] As a preferred embodiment of the present invention, the particle size of the spent automobile catalyst is 50-200 meshes.

[0017] As a preferred embodiment of the present invention, the smelting temperature is 900-1050° C., the smelting time is 30 min-120 min, and the smelting process is carried out in nitrogen.

[0018] As a preferred embodiment of the present invention, the vacuum distillation temperature is 950-1250° C. and the pressure is 1-30 Pa.

[0019] The present invention uses auxiliary materials to reduce the melting point of materials, slags the elements such as calcium, magnesium, silicon in the catalyst, and reduces metal oxides to metals. In addition, the method uses lead, copper, silver and other metals in the silver-containing copper slag to smelt and capture platinum, palladium and rhodium in the spent automobile catalyst to form a precious metal alloy, and then uses the difference in saturated vapor pressure of each valuable element to separate base metals such as lead, bismuth and antimony from precious metals by vacuum distillation, and finally achieves efficient enrichment of precious metals in the silver-containing copper slag and spent automobile catalysts, and the formed precious metal alloy can be used to recover precious metals such as silver, gold, platinum, palladium and rhodium by step refining.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention is based on multi-metal smelting capture and vacuum distillation, realizes the comprehensive recovery of valuable elements in two secondary resources, especially the efficient enrichment of silver, gold and platinum group metals, and enriches the platinum group metals in the refractory cordierite-type carrier catalyst into a silver-copper alloy, providing convenience for the subsequent refining of precious metals, shortening the precious metal refining process, and the process is a physical method, efficient and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention provides a flow chart of the method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts. DETAILED DESCRIPTION

[0022] 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.

[0023] Example 1

[0024] The silver-containing copper slag in this embodiment is high-silver copper slag containing Ag 19.31%, Au 50g / t, Cu 38.76%, Pb 14.78%, Bi4.50%, Sb 7.55%, and the rest is non-metallic elements such as oxygen and sulfur. The auxiliary material is a mixed powder of 100g charcoal powder, 100g borax and 100g silicon dioxide powder. The content components of the automobile spent catalyst include Pt 523g / t, Pd1356g / t, and Rh 245g / t.

[0025] A method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts, specifically comprising the following steps:

[0026] (1) 1 kg of silver-containing copper slag, 1 kg of spent automobile catalyst, and 300 g of auxiliary materials are uniformly mixed to obtain a mixed slag material;

[0027] (2) smelting the mixed slag at 1000° C. for 60 min to obtain slag and a multi-metal alloy product;

[0028] (3) The multi-metal alloy is vacuum distilled at 1000° C. for 60 min with the pressure maintained at 20 Pa to obtain base metal volatiles and noble metal residues.

[0029] Example 2

[0030] The silver-containing copper slag in this embodiment is Ag 25.31%, Au 109g / t, Cu 32.78%, Pb 30.56%, Bi9.93%, Sb 3.42%, and the rest is high-silver copper slag of non-metallic elements such as oxygen and sulfur. The auxiliary material is a mixed powder of 100g activated carbon powder, 100g sodium borate and 100g calcium oxide silicon powder. The content components of the automobile spent catalyst include Pt 789g / t, Pd 1684g / t, and Rh 475g / t.

[0031] A method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts, specifically comprising the following steps:

[0032] (1) 1 kg of silver-containing copper slag, 1 kg of spent automobile catalyst, and 300 g of auxiliary materials are uniformly mixed to obtain a mixed slag material;

[0033] (2) smelting the mixed slag at 1050° C. for 60 min to obtain slag and a multi-metal alloy product;

[0034] (3) The multi-metal alloy is vacuum distilled at 1050° C. for 60 min with the pressure maintained at 20 Pa to obtain base metal volatiles and noble metal residues.

[0035] Example 3

[0036] The silver-containing copper slag in this embodiment is high-silver copper slag containing Ag 19.31%, Au 50g / t, Cu 38.76%, Pb 14.78%, Bi4.50%, Sb 7.55%, and the rest is non-metallic elements such as oxygen and sulfur. The auxiliary material is a mixed powder of 100g flour. The content components of the automobile spent catalyst include Pt 523g / t, Pd 1356g / t, and Rh 245g / t.

[0037] A method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts, specifically comprising the following steps:

[0038] (1) 0.5 kg of silver-containing copper slag, 0.5 kg of spent automobile catalyst, and 100 g of auxiliary materials are uniformly mixed to obtain a mixed slag material;

[0039] (2) smelting the mixed slag at 900° C. for 120 min to obtain slag and a multi-metal alloy product;

[0040] (3) The multi-metal alloy is vacuum distilled at 950° C. for 60 min with the pressure maintained at 30 Pa to obtain base metal volatiles and noble metal residues.

[0041] Example 4

[0042] The silver-containing copper slag in this embodiment is high-silver copper slag containing Ag 19.31%, Au 50g / t, Cu 38.76%, Pb 14.78%, Bi4.50%, Sb 7.55%, and the rest is non-metallic elements such as oxygen and sulfur. The auxiliary material is a mixed powder of 200g coke. The content components of the automotive spent catalyst include Pt 523g / t, Pd 1356g / t, and Rh 245g / t.

[0043] A method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts, specifically comprising the following steps:

[0044] (1) 1 kg of silver-containing copper slag, 0.5 kg of spent automobile catalyst, and 200 g of auxiliary materials are uniformly mixed to obtain a mixed slag material;

[0045] (2) smelting the mixed slag at 1000° C. for 30 min to obtain slag and a multi-metal alloy product;

[0046] (3) The multi-metal alloy is vacuum distilled at 1250° C. for 60 min with the pressure maintained at 1 Pa to obtain base metal volatiles and noble metal residues.

[0047] Comparative Example 1

[0048] The method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts described in this comparative example is different from that in Example 1 in that the auxiliary material is sodium bisulfate.

[0049] Comparative Example 2

[0050] The method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts described in this comparative example is different from that in Example 1 in that the auxiliary material is sulfur.

[0051] Comparative Example 3

[0052] The auxiliary material in this comparative example is a mixed powder of 100g charcoal powder, 100g borax and 100g silicon dioxide powder. The content components of the automobile spent catalyst include Pt 523g / t, Pd 1356g / t, and Rh 245g / t.

[0053] A method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts, specifically comprising the following steps:

[0054] (1) 1 kg of spent automobile catalyst and 300 g of auxiliary materials were uniformly mixed to obtain a mixed slag material;

[0055] (2) smelting the mixed slag at 1000° C. for 60 min to obtain slag and a multi-metal alloy product;

[0056] (3) The multi-metal alloy is vacuum distilled at 1000° C. for 60 min with the pressure maintained at 20 Pa to obtain base metal volatiles and noble metal residues.

[0057] Comparative Example 4

[0058] The silver-containing copper slag in this comparative example is high-silver copper slag containing Ag 19.31%, Au 50g / t, Cu 38.76%, Pb 14.78%, Bi 4.50%, Sb 7.55%, and the rest is non-metallic elements such as oxygen and sulfur. The auxiliary material is a mixed powder of 100g charcoal powder, 100g borax and 100g silicon dioxide powder.

[0059] A method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts, specifically comprising the following steps:

[0060] (1) 1 kg of silver-containing copper slag and 300 g of auxiliary materials are uniformly mixed to obtain a mixed slag material;

[0061] (2) smelting the mixed slag at 1000° C. for 60 min to obtain slag and a multi-metal alloy product;

[0062] (3) The multi-metal alloy is vacuum distilled at 1000° C. for 60 min with the pressure maintained at 20 Pa to obtain base metal volatiles and noble metal residues.

[0063] Comparative Example 5

[0064] The silver-containing copper slag in this comparative example is high-silver copper slag containing Ag 19.31%, Au 50g / t, Cu 38.76%, Pb 14.78%, Bi 4.50%, Sb 7.55%, and the rest is non-metallic elements such as oxygen and sulfur. The auxiliary material is a mixed powder of 100g charcoal powder, 100g borax and 100g silicon dioxide powder. The content components of the automobile spent catalyst include Pt 523g / t, Pd 1356g / t, and Rh 245g / t.

[0065] A method for recovering precious metals by using silver-containing copper slag in conjunction with spent automobile catalysts, specifically comprising the following steps:

[0066] (1) 1 kg of silver-containing copper slag, 1 kg of spent automobile catalyst, and 300 g of auxiliary materials are uniformly mixed to obtain a mixed slag material;

[0067] (2) subjecting the mixed slag to vacuum distillation at 1000° C. for 60 min, with the pressure maintained at 20 Pa, to obtain slag and a multi-metal alloy product;

[0068] (3) The multi-metal alloy is vacuum distilled at 1000° C. for 60 min with the pressure maintained at 20 Pa to obtain base metal volatiles and noble metal residues.

[0069] Effect example

[0070] The base metal volatiles and noble metal residues obtained in the examples and comparative examples were tested for metal content by chemical titration combined with inductively coupled plasma emission spectrometry, and the results are shown in Table 1:

[0071] Table 1

[0072]

[0073]

[0074]

[0075] According to Table 1, the direct recovery rate of valuable metals in Examples 1-4 of the present invention is much higher than that in Comparative Examples 1-4. According to Example 1 and Comparative Examples 1-2, it can be seen that the auxiliary material is replaced with sodium bisulfate or sulfur, which makes it impossible to directly recover the valuable metals. This is mainly because the present invention uses auxiliary materials to reduce the melting point of the material, slags the elements such as Ca, Mg, Si in the catalyst, and reduces the metal oxides to metals, while sodium bisulfate or sulfur does not have the effect of reducing oxides and reducing melting points, so the efficient enrichment and recovery of platinum palladium rhodium is not achieved, resulting in a low direct recovery rate of platinum palladium rhodium, which in turn causes the valuable metals to be unable to be recovered. According to Example 1 and Comparative Examples 3-4, the lack of high-silver copper slag is equivalent to the lack of metal trapping agent. The present invention lacks silver-containing copper slag or automobile failure catalyst and cannot achieve the recovery of platinum group metals and the high recovery of base metals, indicating that there is a synergistic effect between the silver-containing copper slag and the automobile failure catalyst, which can capture precious metal alloys or base metals with each other and jointly achieve a high direct recovery rate of valuable metals. According to Example 1 and Comparative Example 5, it can be seen that the silver-containing copper slag and the spent automobile catalyst must undergo a coordinated process of smelting and vacuum distillation in order to achieve the direct recovery of precious metals and increase the direct recovery rate of base metals. If the coordinated process is lacking, the capture effect of the metals in the silver-copper slag on the waste catalyst cannot be achieved, the waste catalyst is separated from the silver-copper slag in the form of slag, and the platinum group metals are not captured.

[0076] 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 recovering precious metals from silver-containing copper slag in cooperation with spent automobile catalysts, characterized in that: The following steps are involved: (1) uniformly mixing silver-containing copper slag, spent automobile catalyst and flour to obtain a mixed slag material; the mass ratio of the silver-containing copper slag, spent automobile catalyst and flour is 0.5:0.5:0.1; (2) smelting the mixed slag at 900° C. for 120 min to obtain slag and a multi-metal alloy product; The smelting process is carried out in nitrogen; (3) vacuum distilling the multi-metal alloy at 950° C. for 60 min with the pressure maintained at 30 Pa to obtain base metal volatiles and noble metal residues; The silver-containing copper slag is an intermediate byproduct of non-ferrous metal smelting or secondary resource recovery, and its composition and content are Ag 10-30%, Au 10-5000g / t, Cu 10-40%, Pb 5-30%, Sb 1-10%, Bi 1-15%, and the rest is high-silver copper slag of non-metallic elements such as oxygen and sulfur; The automobile spent catalyst is cordierite-type automobile spent purifier powder.

2. The method for recovering precious metals from silver-containing copper slag in cooperation with spent automobile catalysts as claimed in claim 1, characterized in that: The particle size of the spent automobile catalyst is 50-200 meshes.

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