Method for efficiently treating high-arsenic precious lead in short process

Abstract

The invention belongs to the technical field of non-ferrous metal smelting, and particularly relates to a short-process high-efficiency treatment method for high-arsenic precious lead, which is suitable for the treatment of a by-product precious lead in reduction smelting of lead anode slime containing complex components such as gold, silver, arsenic and the like and the recovery process of precious metals. According to the method, the high-arsenic precious lead and the lead-bismuth alloy are mixed according to a certain proportion, so that the material components entering the furnace can enter the continuous vacuum distillation furnace to be subjected to continuous vacuum distillation, the smelting period is remarkably shortened, and the energy consumption is reduced. According to the method, the content of arsenic, copper and antimony in precious lead can be remarkably reduced, the impurity smoke entrainment loss of metal silver is reduced, and the silver enrichment multiple is increased. Compared with a traditional pyrogenic process antimony running furnace process, the method adopts a vacuum metallurgy means, is green and environment-friendly, is short in treatment period, and can efficiently produce the high-silver alloy.

Description

Technical Field

[0001] The present invention belongs to the technical field of nonferrous metal smelting, and specifically relates to a short-process method for efficiently treating high-arsenic noble lead, which is suitable for recovering precious metals such as gold and silver from high-lead noble arsenic. Background Art

[0002] Precious lead is a crude lead alloy containing metals such as gold, silver, arsenic, antimony, bismuth, and copper. It mainly comes from the pyrometallurgical treatment of lead / copper anode mud or lead smelting by-products. Recovering gold, silver and other precious metals from precious lead is a core link in resource recycling, cost reduction and efficiency improvement, and green metallurgy.

[0003] The traditional pyrometallurgical recovery process involves oxidizing and refining precious lead to produce a crude silver alloy. This stage requires 6-7 days for a single furnace to process 3-4 tons of precious lead containing silver metal. The crude silver alloy is then subjected to oxidative refining to further remove impurities, ultimately yielding a gold-silver alloy. The total process takes 7-8 days. This process relies on high-temperature oxidation, and while the technology is mature, it suffers from long smelting cycles, high energy consumption, significant pollution, and low silver recovery rates.

[0004] In recent years, technology has shifted toward vacuum distillation, whereby precious lead is continuously vacuum-distilled to produce high-silver precious lead. This process takes only one to two days, and the high-silver precious lead is then oxidized and smelted for three to four days to produce a gold-silver alloy. This effectively addresses the challenges of traditional pyrometallurgical smelting, but it cannot directly process high-arsenic precious lead. High-arsenic precious lead has poor fluidity due to its presence of multiple high-melting-point components. For example, the melting points of gold, silver, arsenic, copper, and antimony are 1064°C, 961°C, 817°C, 1084°C, and 630°C, respectively. Therefore, direct feeding of high-arsenic precious lead into the furnace can lead to difficulties in smelting and pipeline blockage. Furthermore, high-arsenic precious lead readily forms highly volatile As₂O₃ at high temperatures, and its vapors can carry micron-sized silver particles into the smoke. The copper smelting process also carries metallic silver into the slag, reducing silver recovery. Summary of the Invention

[0005] In view of the problems existing in the background technology, the purpose of the present invention is to provide a short-process method for efficiently treating high-arsenic noble lead.

[0006] To achieve the above object, the technical solution of the present invention is: A short-process and efficient method for treating high-arsenic noble lead comprises the following steps: Step 1: Mix high-arsenic noble lead and low-arsenic lead-bismuth alloy in a mass ratio of 1:1-2, so that the mass percentage of the mixed material components is controlled to be As≤5%, Cu≤4%, and Sb≤20%; Step 2: Put the mixed material into the melting pot to melt, remove the precious lead slag to recover silver; Step 3: putting the mixed material after the slag removal process into a continuous vacuum distillation furnace for continuous vacuum distillation; Step 4: After continuous vacuum distillation, three components are produced: arsenic-antimony alloy, volatile antimony-bismuth alloy, and residual high-silver precious lead. The residual high-silver precious lead is directly put into the silver separation furnace for oxidation and crude refining to recover silver metal.

[0007] Preferably, the high-arsenic noble lead in step one comprises the following components in mass percentage: Ag 10%~15%, Au 0.01%~0.03%, Pb 20%~30%, Cu 5%~8%, As 5%~10%, Sb 25%~35%, and Bi 5%~10%.

[0008] Preferably, the lead-bismuth alloy in step 1 comprises the following components in mass percentage: Ag 0.1%-0.5%, Pb 20%-30%, Cu 0%-0.5%, As 0%-0.1%, Sb 0%-0.5%, and Bi 70%-80%.

[0009] Preferably, the process parameters of the continuous vacuum distillation treatment in step three are as follows: temperature of 1000-1300° C., vacuum degree of 5 Pa, and time of 20 hours.

[0010] Preferably, the residual high-silver precious lead in step 4 comprises the following components in mass percentage: As 0%~1%, Cu 10%~20%, Sb 20%~30%, Pb 3%~5%, Bi 1%~5%, Ag 40%~50%; the silver enrichment multiple in the residual high-silver precious lead is more than 4 times that of the raw material precious lead, and the arsenic separation and removal rate is greater than 90%.

[0011] The beneficial effects of the present invention are: By combining low-arsenic lead-bismuth alloy with high-arsenic noble lead, the physical properties of the materials entering the furnace are improved. The low melting point and good fluidity of the lead-bismuth alloy under vacuum distillation conditions are utilized to reduce the viscosity of the mixed materials and avoid the problem of pipe clogging caused by the chemical materials. The high-arsenic noble lead can be directly subjected to a continuous vacuum distillation furnace, realizing the de-arsenic and silver-enrichment steps in one, greatly simplifying the process flow, significantly shortening the smelting cycle, and reducing energy consumption. This method can also reduce the arsenic, copper, and antimony contents of the materials entering the furnace, reduce the entrainment and loss of metallic silver during the smelting process, and improve the silver recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a process flow chart for the treatment of high-arsenic noble lead in the present invention. DETAILED DESCRIPTION

[0013] Example 1 The composition of a batch of precious lead is: Ag 11.2%, Au 0.013%, Pb 22%, Cu 6.8%, As 9.4%, Sb 28.9%, Bi 7.6%; the composition of a batch of lead-bismuth alloy is: Ag 0.23%, Pb 28%, Cu 0.26%, As 0.04%, Sb 0.32%, Bi78%.

[0014] After the above precious lead and lead-bismuth alloy are mixed in a mass ratio of 1:1, the mixture composition is: Ag 5.72%, As 4.72%, Cu 3.53%, Sb 14.61%, Bi 42.8%.

[0015] The mixed material was melted in a melting pot, and the slag was removed. After vacuum distillation for 20 hours at a vacuum melting temperature of 1100°C and a vacuum degree of 5Pa, arsenic-antimony alloy, volatile antimony-bismuth alloy, and residual high-silver precious lead were produced and sampled for analysis.

[0016] The product analysis is as follows: The silver enrichment ratio of the residual high-silver precious lead is 4.29 times that of the raw material precious lead, and the arsenic separation and removal rate is 94.04%. The residual high-silver precious lead of this batch enters the silver separation furnace for oxidation and crude refining. The time required for smelting 3-4 tons of silver metal in a single furnace is shortened to 3.5 days, which is half of the original process.

Claims

1. A short-process and efficient method for treating high-arsenic noble lead, characterized in that: The following steps are involved: Step 1: Mix high-arsenic noble lead and low-arsenic lead-bismuth alloy in a mass ratio of 1:1-2, so that the mass percentage of the mixed material components is controlled to be As≤5%, Cu≤4%, and Sb≤20%; Step 2: Put the mixed material into the melting pot to melt, remove the precious lead slag to recover silver; Step 3: putting the mixed material after the slag removal process into a continuous vacuum distillation furnace for continuous vacuum distillation; Step 4: After continuous vacuum distillation, three components are produced: arsenic-antimony alloy, volatile antimony-bismuth alloy, and residual high-silver precious lead. The residual high-silver precious lead is directly put into the silver separation furnace for oxidation and crude refining to recover silver metal.

2. The method according to claim 1, wherein: The high-arsenic noble lead in step 1 includes the following components in mass percentage: Ag 10%-15%, Au 0.01%-0.03%, Pb 20%-30%, Cu 5%-8%, As 5%-10%, Sb 25%-35%, and Bi 5%-10%.

3. The method according to claim 1, wherein: The lead-bismuth alloy in step 1 comprises the following components in mass percentage: Ag 0.1%-0.5%, Pb 20%-30%, Cu 0%-0.5%, As 0%-0.1%, Sb 0%-0.5%, and Bi 70%-80%.

4. The method according to claim 1, wherein: The process parameters of the continuous vacuum distillation treatment in step 3 are as follows: temperature of 1000-1300° C., vacuum degree of 5 Pa, and time of 20 hours.

5. The method according to claim 1, wherein: The residual high-silver precious lead in step 4 includes the following components in mass percentage: As 0%~1%, Cu 10%~20%, Sb 20%~30%, Pb 3%~5%, Bi 1%~5%, and Ag 40%~50%. The silver enrichment multiple in the residual high-silver precious lead is more than 4 times that of the raw material precious lead, and the arsenic separation and removal rate is greater than 90%.

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