Method for producing antimony white by directly oxidizing crude antimony

Abstract

The invention belongs to the technical field of metallurgy, and relates to a method for producing antimony white by directly oxidizing crude antimony, which comprises the following steps: S1, mixing crude antimony with crude antimony alloy, reacting in an oxygen-containing atmosphere, and obtaining oxidizing slag and melt after the reaction is finished; and S2, the temperature of the melt is adjusted, then compressed air is introduced for a reaction, flue gas containing antimony trioxide is generated, and antimony oxide slag is obtained after the reaction is finished. According to the method, sodium sulfide, sodium hydroxide, sodium thiosulfate and other impurity components contained in crude antimony are fully utilized, and the components are innovatively utilized for arsenic removal reaction, so that the tedious step of adding various auxiliary materials in the traditional process is avoided; and the original sodium sulfide, sodium hydroxide and sodium thiosulfate in the crude antimony can fully exert a synergistic effect, so that the arsenic removal agent shows excellent performance in the arsenic removal effect, the process flow is simplified, the production cost is also remarkably reduced, and the economic benefit and the process efficiency are both improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for directly oxidizing crude antimony to produce antimony white. Background Art

[0002] In the non-ferrous metal smelting process, lead anode slime, a byproduct with significant recycling value, undergoes advanced processing in a converter reduction smelting process to produce a crude antimony alloy as an intermediate product. However, because this process utilizes high-temperature pyrometallurgical reduction, it inevitably introduces some impurities, the most common of which is harmful impurities such as elemental arsenic. Meanwhile, antimony-bearing gold concentrate can also be effectively produced as a crude antimony product through alkaline electrowinning, a typical hydrometallurgical process. During the electrowinning process in an alkaline sodium thioantimonite solution, antimony precipitation occurs at the cathode, while sodium sulfide is produced as a byproduct at the anode. Notably, during the electrowinning process, some sodium sulfide undergoes oxidation with dissolved oxygen, converting it to sodium thiosulfate. Due to the high concentrations of salts and alkalis in the electrolyte, the antimony product precipitated at the cathode is mechanically contaminated with significant amounts of impurities such as sodium hydroxide, sodium sulfide, and sodium thiosulfate. The presence of these impurities significantly affects the purity of the final product.

[0003] In the production of antimony white, whether using crude antimony alloy or crude antimony as raw material, impurity removal is an essential pretreatment step. The currently commonly used method for removing impurities from crude antimony alloys is a chemical process that adds an alkaline flux and an oxidant. Specifically, the alkaline flux is usually sodium carbonate (Na2CO3) or sodium hydroxide (NaOH), while the oxidant is usually a chemical reagent such as sodium nitrate (NaNO3) or potassium nitrate (KNO3). These additives, in the molten state at high temperatures, undergo complex redox reactions with the arsenic in the alloy, converting the harmful arsenic into arsenate compounds. Because the density of arsenate is significantly lower than that of molten antimony, it floats to the surface as scum and accumulates on the melt surface. Mechanical scraping can achieve a preliminary separation of arsenic and antimony. However, this arsenic removal method has significant drawbacks: it requires a large amount of chemical auxiliary materials, resulting in high production costs; and its arsenic removal efficiency is limited, making it difficult to meet the requirements for high-quality antimony white production. As for the removal of impurities from crude antimony raw materials, a physical and chemical combined crushing-washing process is mainly used. This process first crushes the crude antimony to a suitable particle size, and then removes mechanically entrained soluble impurities such as sodium hydroxide, sodium sulfide and sodium thiosulfate through water washing. However, this method will produce a large amount of strongly alkaline industrial wastewater containing sulfide components. These wastewaters not only have extremely high pH values, but also contain a variety of harmful substances, which bring great difficulties to subsequent wastewater treatment and significantly increase the cost of environmental protection management. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for directly oxidizing crude antimony to produce antimony white.

[0005] The specific technical solutions are as follows:

[0006] The method for directly oxidizing crude antimony to produce antimony white comprises the following steps:

[0007] S1: Mixing crude antimony with crude antimony alloy, reacting in an oxygen-containing atmosphere, and obtaining oxide slag and melt after the reaction;

[0008] S2 adjusts the melt temperature, then introduces compressed air for reaction, generating fume containing antimony trioxide, and antimony oxide slag is obtained after the reaction is completed.

[0009] Among them, crude antimony comes from the product produced by the alkaline leaching-electrowinning process of antimony-containing gold concentrate, and its main components are: Sb content ≥ 85wt%, NaOH content 3.0wt%~6.0wt%, Na2S content 3.0wt%~6.0wt%, Na2S2O3 content 1.0wt%~3.0wt%;

[0010] Crude antimony alloy is the product produced by high-temperature reduction of lead anode mud, and its main components are: Sb content ≥85wt%, Au content ≤0.5wt%, Ag content ≤0.5wt%, As content ≤5.0wt%, Te content ≤0.1wt%, Se content ≤0.1wt%, and Bi content ≤0.1wt%.

[0011] The reaction mechanism of the present invention is as follows:

[0012] The impurities in crude antimony mainly include sodium sulfide, sodium hydroxide and sodium thiosulfate, while the impurities in crude antimony alloy mainly include arsenic. The present invention utilizes the synergistic effect of crude antimony and crude antimony alloy in an oxygen-containing atmosphere, so that the impurity components in the two are transformed into a slag phase, thereby achieving effective separation and removal of impurities and antimony.

[0013] In step S1, sodium sulfide, sodium hydroxide, and sodium thiosulfate in crude antimony react with arsenic in crude antimony alloy in an oxygen-containing atmosphere to form oxidized slag, thereby separating impurities from antimony. The main reactions are: 4As+Na2S+7O2+4NaOH→4NaAsO3+Na2SO4+2H2O↑; 4As+Na2S2O3+7O2+6NaOH→4NaAsO3+2Na2SO4+3H2O↑; Na2S+2O2→Na2SO4; 2Na2S2O3+3O2→2Na2SO4+2SO2↑; Na2S2O3+2O2+2NaOH→2Na2SO4+H2O↑.

[0014] Furthermore, in step S1, before mixing, the crude antimony and the crude antimony alloy are crushed to a particle size of ≤5 cm.

[0015] Furthermore, in step S1, the mixing mass ratio of crude antimony to crude antimony alloy is (1.5~2):1.

[0016] Furthermore, in step S1, the oxygen-containing atmosphere is air.

[0017] Furthermore, in step S1, the specific reaction process is: raising the temperature to 650-700° C., and maintaining the temperature constant for 1-3 hours after the crude antimony and the crude antimony alloy are completely melted.

[0018] Preferably, in step S1, after the reaction is completed, the oxidation slag is removed by scraping.

[0019] In step S2, the antimony in the melt reacts fully with the oxygen in the compressed air to generate flue gas containing antimony trioxide. The main reactions are: 4Sb+3O2→2Sb2O3↑.

[0020] Furthermore, in step S2, the melt temperature is adjusted to 630-650° C., and the reaction time is 4-8 hours.

[0021] Furthermore, in step S2, the compressed air has a pressure of 0.1-0.3 MPa and a gas flow rate of 5000-7000 Nm 3 / h.

[0022] Furthermore, step S2 further includes cooling the flue gas obtained in step S2 to below 350° C. to collect antimony white; the antimony white meets the grade requirement of Sb2O399.90 in GB / T 4062-2013.

[0023] Preferably, in step S2, the antimony oxide slag is returned to the anode mud treatment system to recover the valuable metals therein.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention makes full use of impurity components such as sodium sulfide, sodium hydroxide and sodium thiosulfate contained in crude antimony, and innovatively uses these components to carry out arsenic removal reaction, which not only avoids the tedious steps of adding various auxiliary materials in traditional processes, but also allows the original sodium sulfide, sodium hydroxide and sodium thiosulfate in crude antimony to fully exert their synergistic effect and show excellent performance in arsenic removal. At the same time, since no additional auxiliary materials are required, not only the process flow is simplified, but also the production cost is significantly reduced, achieving a dual improvement in economic benefits and process efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a process flow chart of the method for directly oxidizing crude antimony to produce antimony white in a specific embodiment. DETAILED DESCRIPTION

[0027] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings and examples. The following examples are intended to illustrate the present invention but are not intended to limit the scope of the invention. The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial sources.

[0028] Example 1

[0029] A method for directly oxidizing crude antimony to produce antimony white, wherein:

[0030] Crude antimony comes from the product produced by the alkaline leaching-electrowinning process of antimony-containing gold concentrate. Its main components are: Sb content 85.36wt%, NaOH content 5.86wt%, Na2S content 5.91wt%, and Na2S2O3 content 2.84wt%.

[0031] Crude antimony alloy comes from the product produced by high-temperature reduction of lead anode mud. Its main components are: Sb content is 94.38wt%, Au content is 0.11wt%, Ag content is 0.14wt%, As content is 1.34wt%, Te content is 0.02wt%, Se content is 0.02wt%, and Bi content is 0.05wt%.

[0032] The steps are as follows:

[0033] S1. Crush crude antimony and crude antimony alloy to a particle size of ≤5 cm, then mix them in an oxidation pot at a mass ratio of 2:1. Raise the temperature to 700°C in an air atmosphere. After the crude antimony and crude antimony alloy are completely melted at 700°C, maintain the temperature constant and react for 1.5 hours. After the reaction is completed, obtain oxide slag and melt. Remove the oxide slag on the upper layer of the melt by skimming.

[0034] S2 adjusts the melt temperature to 650℃ and then presses 7000Nm 3 Compressed air with a wind pressure of 0.3 MPa is introduced at a flow rate of / h. The reaction is carried out at this temperature for 4 hours to produce flue gas containing antimony trioxide. After the reaction, antimony oxide slag is obtained. The flue gas is cooled to 350℃ to collect antimony white. The antimony oxide slag is returned to the anode mud treatment system to recover valuable metals such as antimony white, gold ingots, silver ingots, selenium dioxide, copper matte, and tellurium ingots. Among them, the purity of antimony white is 99.94wt%, and the antimony recovery rate is 92.35%.

[0035] Example 2

[0036] A method for directly oxidizing crude antimony to produce antimony white, wherein:

[0037] Crude antimony comes from the product produced by the alkaline leaching-electrowinning process of antimony-containing gold concentrate. Its main components are: Sb content 92.34wt%, NaOH content 3.21wt%, Na2S content 3.28wt%, Na2S2O3 content 1.32wt%;

[0038] Crude antimony alloy comes from the product produced by high-temperature reduction of lead anode mud. Its main components are: Sb content is 85.27wt%, Au content is 0.21wt%, Ag content is 0.45wt%, As content is 4.92wt%, Te content is 0.03wt%, Se content is 0.05wt%, and Bi content is 0.08wt%.

[0039] The steps are as follows:

[0040] S1. Crude antimony and crude antimony alloy are crushed to a particle size of ≤5 cm, then mixed in an oxidation pot at a mass ratio of 1.5:1. In an air atmosphere, the temperature is raised to 650°C. After the crude antimony and crude antimony alloy are completely melted at 650°C, the temperature is maintained constant and the reaction is continued for 3 hours. After the reaction is completed, oxide slag and melt are obtained. The oxide slag on the upper layer of the melt is removed by skimming.

[0041] S2 adjusts the melt temperature to 640℃ and then presses 6000Nm 3 Compressed air with a wind pressure of 0.2 MPa is introduced at a flow rate of / h. The reaction is carried out at this temperature for 8 hours to produce flue gas containing antimony trioxide. After the reaction, antimony oxide slag is obtained. The flue gas is cooled to 300℃ to collect antimony white. The antimony oxide slag is returned to the anode mud treatment system to recover valuable metals such as antimony white, gold ingots, silver ingots, selenium dioxide, copper matte, and tellurium ingots. Among them, the purity of antimony white is 99.92wt%, and the antimony recovery rate is 93.08%.

[0042] Example 3

[0043] A method for directly oxidizing crude antimony to produce antimony white, wherein:

[0044] Crude antimony comes from the product produced by the alkaline leaching-electrowinning process of antimony-containing gold concentrate. Its main components are: Sb content 88.36wt%, NaOH content 4.95wt%, Na2S content 5.14wt%, Na2S2O3 content 2.98wt%;

[0045] Crude antimony alloy comes from the product produced by high-temperature reduction of lead anode mud. Its main components are: Sb content is 87.25wt%, Au content is 0.10wt%, Ag content is 0.34wt%, As content is 3.21wt%, Te content is 0.08wt%, Se content is 0.05wt%, and Bi content is 0.06wt%.

[0046] The steps are as follows:

[0047] S1: Crude antimony and crude antimony alloy are crushed to a particle size of ≤5 cm, and then mixed in an oxidation pot at a mass ratio of crude antimony to crude antimony alloy of 1.8:1. In an air atmosphere, the temperature is raised to 680°C. After the crude antimony and crude antimony alloy are completely melted at 680°C, the temperature is maintained constant for 1 hour. After the reaction is completed, oxide slag and melt are obtained, and the oxide slag on the upper layer of the melt is removed by skimming;

[0048] S2 adjusts the melt temperature to 630℃ and then presses 5000Nm 3 Compressed air with a wind pressure of 0.1 MPa is introduced at a flow rate of / h. The reaction is carried out at this temperature for 6 hours to produce flue gas containing antimony trioxide. After the reaction, antimony oxide slag is obtained. The flue gas is cooled to 350℃ to collect antimony white. The antimony oxide slag is returned to the anode mud treatment system to recover valuable metals such as antimony white, gold ingots, silver ingots, selenium dioxide, copper matte, and tellurium ingots. Among them, the purity of antimony white is 99.91wt%, and the antimony recovery rate is 92.18%.

[0049] test

[0050] The arsenic content in the oxidized slag and melt obtained in step S1 of Examples 1 to 3 was detected, and the results are shown in Table 1.

[0051] The determination of arsenic content in the melt shall be carried out in accordance with the "Chemical Analysis Methods for Crude Antimony Part 3: Determination of Arsenic, Lead, Copper, Selenium and Iron Contents by Inductively Coupled Plasma Atomic Emission Spectrometry (YS / T 1582.3-2022)", and the determination of arsenic content in oxide slag shall be carried out in accordance with the "Chemical Analysis Methods for Silver Separation Slag from Lead Smelting Part 7: Determination of Arsenic Content by Inductively Coupled Plasma Atomic Emission Spectrometry (YS / T 1348.7-2021)".

[0052] Table 1 Arsenic content in slag and melt

[0053] As shown in Table 1, the arsenic content in the melts was less than 0.02 wt%, indicating that the mixed smelting of crude antimony and crude antimony alloys achieved good arsenic removal results. The antimony white produced in Examples 1-3 all met the Sb2O3 grade requirement of 99.90 in GB / T 4062-2013.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for producing antimony white by direct oxidation of crude antimony, characterized in that: The steps include: S1: Mixing crude antimony with crude antimony alloy, reacting in an oxygen-containing atmosphere, and obtaining oxide slag and melt after the reaction; S2 adjusts the melt temperature, then introduces compressed air for reaction, generating fume containing antimony trioxide, and antimony oxide slag is obtained after the reaction is completed.

2. The method according to claim 1, characterized in that In step S1, before mixing, the crude antimony and the crude antimony alloy are crushed to a particle size of ≤5 cm.

3. The method according to claim 1, characterized in that In step S1, the mixing mass ratio of crude antimony to crude antimony alloy is (1.5-2):

1.

4. The method according to claim 1, wherein In step S1 , the oxygen-containing atmosphere is air.

5. The method according to claim 1, wherein In step S1, the specific reaction process is: raising the temperature to 650-700° C., and maintaining the temperature constant for 1-3 hours after the crude antimony and the crude antimony alloy are completely melted.

6. The method according to claim 5, characterized in that In step S1, after the reaction is completed, the oxidation slag is removed by scraping.

7. The method according to claim 1, characterized in that In step S2, the compressed air has a pressure of 0.1-0.3 MPa and a gas flow rate of 5000-7000 Nm 3 / h.

8. The method according to claim 1, characterized in that In step S2, the melt temperature is adjusted to 630-650° C., and the reaction time is 4-8 hours.

9. The method according to claim 1, characterized in that Step S2 also includes cooling the flue gas obtained in step S2 to below 350° C. to collect antimony white.

10. The method according to claim 1, characterized in that In step S2, the antimony oxide slag is returned to the anode mud treatment system.

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