A method for removing copper from crude antimony alloy by using antimony crystallization salt

Abstract

The present invention relates to a method for removing copper from crude antimony alloy by using antimony crystallization salt. The technological steps are as follows: The copper-rich antimony smelting slag is proportioned with coke and soda ash for ore blending and reduced smelting under high-temperature conditions to produce a crude antimony alloy containing 1%-3% copper; The crude antimony alloy is added to a refining pot with sodium hydroxide and sodium nitrate mixed in a certain proportion, so that arsenic and copper in the crude antimony alloy enter the slag phase under the action of a strong oxidant, realizing the preliminary separation of copper in the crude antimony alloy; The crude antimony alloy after preliminary copper removal is co-treated with antimony crystallization salt for pyrometallurgical refining to reduce the copper grade in the crude antimony alloy to below 0.03%, which is lower than the national No. 2 antimony standard. The technical solution proposed by the present invention can effectively solve the removal of impurity copper in the antimony production process, realize the open circuit of copper elements, avoid the influence of copper enrichment in the process on the antimony production process, and at the same time, through the co-treatment with antimony crystallization salt, realize the effective recovery of antimony in the crystallization salt, with remarkable economic benefits, and is of great significance for expanding the application field of antimony products in industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of pyrometallurgical processes, and relates to a method for removing copper from crude antimony alloy by using antimony crystallization salt. Background Art

[0002] The traditional pyrometallurgical process for antimony smelting uses stibnite (Sb2S3) as raw material, first roasting in a blast furnace and then reducing and smelting to produce crude antimony. Generally, copper mainly enters the slag phase, and the copper content in crude antimony is small, so there is no need for separate copper removal. However, with the increasingly scarce antimony resources, high-quality antimony ores can no longer meet the development needs of the antimony industry. Crude antimony obtained from roasting and reducing and smelting high-copper antimony slag, reverberatory furnace alkali slag, and bottom water of antimony white furnace, which are by-products of blast furnaces, has become an important secondary resource for antimony smelting. However, the copper grade in the produced crude antimony has increased significantly. In the process of non-ferrous metal antimony smelting, copper elements, as impurity elements, affect the quality of antimony products. The removal of copper from crude antimony by pyrometallurgical refining is currently a difficult problem faced by the antimony industry.

[0003] Antimony crystallization salt is an intermediate material produced during the wet alkaline leaching process of antimony-containing gold concentrate. Its main component is a compound composed of sulfur and antimony elements, belonging to the category of solid waste. At present, there is no suitable treatment process for antimony crystallization salt.

[0004] Regarding the process for removing copper from crude antimony, it is relatively single. Basically, the liquation method or the combined method of liquation - sulfur addition is used for copper removal. For example, Wang Weiguo from Guangxi Wanshizhi Rare and Precious Metals Technology Co., Ltd. proposed a copper remover for antimony smelting production and its application (CN111041231A). By researching and developing a copper remover for antimony smelting production, including elemental sulfur or sulfur-containing compounds, including elemental phosphorus or phosphorus-containing compounds; using the elemental sulfur or sulfur-containing compounds, elemental phosphorus or phosphorus-containing compounds alone or mixing several of them in a certain proportion to prepare a copper remover for antimony refining. Xu Peilun et al. from Mengzi Mining and Metallurgy Co., Ltd. proposed a method for treating antimony-rich high-tin high-copper alloy (CN109306409A), using the temperature to gradually decrease from high to low in sequence

[0005] to separate tin, antimony, and copper. Both of the above processes use the liquation - sulfur addition method for copper removal to separate copper from antimony. However, in order to reduce the copper element grade to a certain range or below, the above processes first need to repeatedly adjust the temperature difference for liquation copper removal, which seriously affects the production efficiency of antimony. Secondly, during the sulfur addition process, sulfur reacts with antimony first and then with copper, requiring an excessive amount of sulfide. The excessive sulfide will form a large amount of solid slag in the subsequent production process, increasing the subsequent environmental protection cost. Summary of the Invention

[0006] In order to overcome the problems existing in the above technologies, the present invention provides a method for removing copper from crude antimony alloy by using antimony crystal salt, which utilizes the complementary advantages of two antimony-containing materials for collaborative treatment to achieve efficient removal of copper in the crude antimony alloy.

[0007] The technical solution of the present invention is realized as follows: A method for removing copper from crude antimony alloy by using antimony crystal salt, comprising the following steps:

[0008] a. Mix antimony smelting slag, coke, and soda ash in a ratio of 100:(5 - 8):(5 - 12) for ore blending, and perform reduction smelting at 1200 - 1250 °C, then cool down to 900 - 1000 °C to produce a crude antimony alloy with a copper grade of 1% - 3%;

[0009] b. Add sodium hydroxide and sodium nitrate mixed in a ratio of 100:(10 - 15):(3 - 5) to the crude antimony alloy in a refining pot at 580 - 650 °C, so that arsenic and copper in the crude antimony alloy form Cu3As and Cu2As and their eutectic compounds with elemental copper under the action of the strong oxidant sodium nitrate and enter the slag phase, realizing the preliminary separation of copper in the crude antimony alloy;

[0010] c. Mix and process the crude antimony alloy obtained in step b with antimony crystal salt in a ratio of 100:(8 - 12), and use the sulfur and antimony elements contained in the antimony crystal salt to react with Cu2Sb in the crude antimony alloy for deep copper removal, reducing the copper grade in the crude antimony alloy to below 0.03%.

[0011] The reaction mechanism is as follows:

[0012] Sb x S y +yCu2Sb=yCu2S+(x + y)Sb

[0013] The method for removing copper from crude antimony alloy by using antimony crystal salt according to the present invention has prominent substantive features and significant technical progress compared with the existing process:

[0014] The method of the present invention has significant advantages such as clear process, easy operation, good environment, and strong process adaptability. It mainly uses the combination of antimony crystal salt and high-copper crude antimony alloy for treatment, utilizes the complementary advantages between elements to remove copper elements, and simultaneously recovers the antimony elements in the antimony crystal salt, having high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the process flow chart of the present invention. EMBODIMENTS

[0016] For better understanding and implementation, the following details a method for removing copper from crude antimony alloy by using antimony crystal salt in conjunction with the accompanying drawings, comprising the following steps:

[0017] Example 1: The content of each element in the high-copper crude antimony alloy is shown in Table 1:

[0018] Table 1 Content of each element in the high-copper crude antimony alloy %

[0019] Element Au* Ag Sb Cu As Content (%) 806 6.99 30.66 2.58 9.50

[0020] Note: The unit of the element with * is g / t.

[0021] The following steps are adopted:

[0022] a. The antimony smelting slag is reductively smelted with coke and soda ash in a proportion of 100:6:10 at 1230 °C, and then cooled to 950 °C to produce a crude antimony alloy with a copper grade of 2.58%. The content of each element in the crude antimony alloy is shown in Table 1;

[0023] b. The crude antimony alloy is added with sodium hydroxide and sodium nitrate mixed in a ratio of 100:12:4 in a refining pot at 620 °C, so that arsenic and copper in the crude antimony alloy form Cu3As and Cu2As and their eutectic compounds with elemental copper under the action of the strong oxidant sodium nitrate and enter the slag phase, realizing the preliminary separation of copper in the crude antimony alloy;

[0024] c. The crude antimony alloy obtained in step b is mixed and processed with antimony crystallization salt in a ratio of 100:10, and the sulfur and antimony elements contained in the antimony crystallization salt react with Cu2Sb in the crude antimony alloy to deeply remove copper, reducing the copper grade in the crude antimony alloy to 0.02%.

[0025] Comparative Example 1: The crude antimony alloy produced by smelting is preliminarily de-coppered in a refining pot at 600 °C without adding any auxiliary materials.

[0026] Comparative Example 2: The crude antimony alloy produced by smelting is added with sodium hydroxide and sodium nitrate mixed in a ratio of 100:10:3 in a refining pot at 600 °C for preliminary de-copper.

[0027] The results of preliminary de-copper in Comparative Example 1 and Comparative Example 2 are as follows:

[0028] Table 2 Content of each element in the crude antimony alloy with no auxiliary material de-copper and preliminary copper removal with sodium hydroxide and sodium nitrate

[0029] Comparative example Excipient Element Au* Ag Sb Cu As Comparative example 1 Blank Content (%) 952 7.23 31.52 2.02 8.23 Comparative example 2 Sodium hydroxide, sodium nitrate Content (%) 1254 9.35 34.25 1.25 2.55

[0030] Note: The unit of the element with * is g / t.

[0031] Table 3 Content of each element in the crude antimony alloy after deep copper removal in Example 1 (%)

[0032] Element Au* Ag Sb Cu As Content (%) 1454 9.55 35.18 0.02 0.12

[0033] Conclusion: By comparing the data of Example 1 with those of Comparative Example 1 and Comparative Example 2, it can be found that in Comparative Example 1, the copper content in the crude antimony alloy after preliminary copper removal without adding any excipients is 2.02%, and in Comparative Example 2, the copper content in the crude antimony alloy after preliminary copper removal with sodium hydroxide and sodium nitrate is 1.25%. After preliminary copper removal and deep copper removal with sodium hydroxide and sodium nitrate in Example 1, the copper element content in the crude antimony alloy is 0.02%. The final copper removal effect of Example 1 is 101 times that of Comparative Example 1 and 62.5 times that of Comparative Example 2, with significant economic benefits.

Claims

1. A method for removing copper from crude antimony alloy by using antimony crystallization salt, characterized in that It includes the following steps: a. Mix antimony smelting slag with coke and soda ash in a ratio of 100:5-8:5-12, and carry out reduction smelting at 1200-1250°C, then cool down to 900-1000°C to produce a crude antimony alloy with a copper grade of 1%-3%; b. Add sodium hydroxide and sodium nitrate mixed in a ratio of 100:10-15:3-5 to the crude antimony alloy in a refining pot at 580-650°C, so that arsenic and copper in the crude antimony alloy form Cu3As and Cu2As under the action of the strong oxidant sodium nitrate and form eutectic compounds with elemental Cu and enter the slag phase, realizing the preliminary separation of copper in the crude antimony alloy; Mix the crude antimony alloy obtained in step b with antimony crystallization salt in a ratio of 100:8-12, and use the sulfur and antimony elements contained in the antimony crystallization salt to react with Cu2Sb in the crude antimony alloy to deeply remove copper, reducing the copper grade in the crude antimony alloy to less than 0.03%. The reaction mechanism is: Sb x S y +yCu2Sb=yCu2S+(x+y)Sb.

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