A method for enriching indium and tin metals from complex hazardous waste materials

Abstract

This invention relates to a method for enriching indium and tin metals from complex hazardous waste materials, comprising the following steps: (1) Indium and tin content detection of materials: analyzing and detecting the content of indium, tin and other valuable metals in antimony-containing hazardous waste materials; (2) Slag formulation: according to the analysis results of antimony-containing hazardous waste materials, adding iron, silicon and calcium to control the slag formulation range; (3) Controlling the oxygen-carbon ratio; (4) Controlling the height of the molten liquid in the reduction furnace to reduce the ash content and improve the enrichment efficiency of indium and tin metals; (5) Heating the molten material; (6) Reduction smelting to produce a lead-antimony alloy, enriching tin in the alloy and indium in the ash. The method of enriching indium and tin metals from complex hazardous waste materials of this invention improves the recovery rate of tin metal by changing the slag formulation and increasing the liquid level height, utilizing the high iron content in the slag to provide conditions for the reduction of tin metal, and at the same time using the high liquid level to reduce the volatilization of tin metal into the ash, thus enriching indium metal in the ash.

Description

Technical Field

[0001] This invention belongs to the field of technology for recovering valuable metals from hazardous waste materials in non-ferrous metal smelting, and specifically relates to a method for enriching indium and tin metals from complex hazardous waste materials. Background Technology

[0002] Traditional methods for recycling lead-antimony hazardous waste involve bottom-blowing and forced-air smelting with lead-antimony sulfide ore. However, lead-antimony sulfide ore is costly with limited potential for appreciation, and the process generates significant dust. Furthermore, the recovery rate of small amounts of metals such as tin contained in the hazardous waste is low, and while indium metal does enter the flue dust, its low content prevents effective utilization. Therefore, how to increase the added value of lead-antimony hazardous waste smelting at low cost has become a hot topic in current hazardous waste smelting research. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a method for enriching indium and tin metals from complex hazardous waste materials. By controlling the slag type and liquid level, the high iron content provides conditions for the reduction of tin metal, thereby improving the recovery rate of tin metal. At the same time, the high liquid level reduces the volatilization of tin metal into the flue dust, thus enriching indium metal in the flue dust.

[0004] The specific technical solution is: a method for enriching indium and tin metals from complex hazardous waste materials, comprising the following steps:

[0005] (1) Detection of indium and tin in materials: Analyze and test the content of indium, tin and other valuable metals in the antimony-containing hazardous waste materials;

[0006] (2) Slag-mixing type: Based on the test and analysis results of antimony-containing hazardous waste, iron, silicon and calcium are added to the antimony-containing hazardous waste to obtain a mixture. The grade range of various elements in the mixture is as follows: ;

[0007] (3) Controlling the oxygen-carbon ratio: Calculate the required amount of pulverized coal based on the metal content of the material fed into the furnace and the heat required for melting, and then deduce the amount of oxygen to ensure a reducing atmosphere in the mixture fed into the furnace, with the oxygen-carbon ratio controlled within a certain range. Within the specified range, the specific adjustments are made according to the three stages of feeding, reduction, and slag discharge in the operation cycle. The reduction time and slag discharge time of the side-blown reduction furnace can be extended or shortened according to the furnace conditions.

[0008] (4) Control the liquid level height: The height of the molten liquid in the reduction furnace is controlled at 1.5 to 1.8 m to reduce the ash rate and improve the enrichment efficiency of indium and tin metals;

[0009] (5) Heating and melting: After the mixed material is put into the furnace, it is heated by the heat of pulverized coal combustion under oxygen-rich conditions, raising the temperature to 1200-1300℃;

[0010] (6) Reduction smelting: When the furnace temperature rises to the predetermined temperature, the oxygen-carbon ratio of the reduction furnace is changed, and the molten metal in the reduction furnace enters the reduction period; high-level smelting is carried out under the strong reducing atmosphere generated by the pulverized coal in the reduction furnace to produce lead-antimony alloy, enriching tin in the alloy and indium in the flue ash.

[0011] Furthermore, the contents of indium, tin and valuable metals in the material described in step (1) are 0.01% to 0.2%, 0.3% to 0.8%, and 30% to 45%, respectively.

[0012] Furthermore, the iron, silicon, and calcium contents in the mixture in step (2) are respectively .

[0013] Furthermore, the times for the three stages of feeding, reduction, and slag discharge in step (3) are 40–50 min, 40–50 min, and 10–20 min, respectively, and the corresponding oxygen-to-carbon ratios for the three stages are respectively... .

[0014] Furthermore, in step (3), the material is smelted under oxygen-enriched conditions after being fed into the furnace, and the following reaction occurs during the smelting process:

[0015] Oxidation reaction: ;

[0016] Main reduction reaction: .

[0017] The beneficial effects of this invention are as follows: This method for enriching indium and tin metals from complex hazardous waste materials improves tin recovery by modifying the slag type and increasing the liquid level. The high iron content in the slag provides conditions for tin metal reduction, while the high liquid level reduces tin metal volatilization into the flue dust, thus enriching indium metal in the flue dust. This invention utilizes relatively inexpensive complex hazardous waste materials, resulting in low production costs. Simultaneously, the direct tin recovery rate is increased by 21.64%, and the indium content in the flue dust increases from 0.12% to 0.97%, significantly improving the recovery rate of indium and tin metals. This process facilitates the integration of hazardous waste resources, improves smelting efficiency, and opens up new technological avenues for further promoting the comprehensive recycling and utilization of hazardous waste materials. Implementation

[0018] To make the technical problems and solutions solved by the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0019] The indium, tin, and valuable metal contents in the complex hazardous waste materials used in this embodiment are 0.01%–0.2%, 0.3%–0.8%, and 30%–45%, respectively.

[0020] This embodiment provides a method for enriching indium and tin metals from complex hazardous waste materials, the steps of which are as follows:

[0021] (1) Detection of tin and indium in materials: The valuable metal components of various complex hazardous waste materials to be put into the furnace are analyzed by chemical analysis to detect the content of tin, indium and other valuable metals;

[0022] (2) Slag-mixing type: Based on the analysis results of the antimony-containing hazardous waste material in step (1), iron, silicon, and calcium are added to make the iron, silicon, and calcium contents in the mixture respectively. The valuable metal content is 30%–45% (the specific content depends on production and operating efficiency), and the high-iron component is used to promote tin recovery, ultimately resulting in a mixture with various element grades ranging from [missing information]. ;

[0023] (3) Controlling the oxygen-carbon ratio: Based on the analysis results of the antimony-containing hazardous waste material in step (1), the required amount of pulverized coal is calculated by the metal content of the material entering the furnace and the heat required for melting (180-200 kg of pulverized coal is consumed per ton of lead). The amount of oxygen is then calculated based on the pulverized coal ratio to ensure a reducing atmosphere in the mixture entering the furnace, and the oxygen-carbon ratio α is controlled within a certain range. Within the specified range, adjustments are made based on the three stages of the operation cycle: feeding, reduction, and slag discharge (the times for the three stages are 40–50 min, 40–50 min, and 10–20 min, respectively, and the corresponding oxygen-to-carbon ratios for the three stages are as follows). During the feeding stage, the oxygen concentration at the primary tuyeres is 65%–72%, and during the reduction period, the oxygen concentration is 45%–50%. The reduction time and slag discharge time of the side-blown reduction furnace can be appropriately extended or shortened according to the furnace conditions.

[0024] (4) Control the liquid level height: Precisely control the height of the molten liquid in the reduction furnace to 1.5-1.8m, effectively reduce the ash rate, increase the indium metal content in the ash, and at the same time reduce the amount of tin metal entering the ash;

[0025] (5) Heating and melting: According to the oxygen-carbon ratio described in step (3), after the mixed material is put into the furnace, it is heated by the heat of pulverized coal combustion under oxygen-rich conditions, and the temperature is raised to 1150-1250℃ (depending on the material and furnace conditions), and the lead temperature of the siphon port is 700-900℃.

[0026] (6) Reduction smelting: When the furnace temperature rises to the predetermined temperature, the molten metal in the reduction furnace enters the reduction period by changing the oxygen-carbon ratio of the reduction furnace. High liquid level (1.5m-1.8m) smelting is carried out under the strong reducing atmosphere generated by pulverized coal to produce lead-antimony alloy, and tin is enriched in the alloy and indium is enriched in the flue ash.

[0027] Table 1 compares the smelting recovery rate and lead-antimony alloy cost using traditional methods for smelting complex lead-antimony hazardous waste materials with the side-blown reduction furnace smelting method used in this embodiment.

[0028] Table 1: Comparison of smelting costs between traditional methods and this embodiment (unit: yuan / ton)

[0029]

[0030] As shown in Table 1, the side-blown reduction furnace smelting method reduces the cost of producing lead-antimony alloy by 380 yuan / ton compared to the traditional method. Simultaneously, the direct recovery rate of antimony increases by 7.81%, the direct recovery rate of tin increases by 21.64%, and the indium content in the flue dust increases from 0.12% to 0.97%. The direct recovery rates of all metals are significantly improved, with particularly high recovery rates for indium and tin. This invention effectively broadens the smelting production process, facilitates the integration of hazardous waste resources, improves smelting efficiency, and effectively shares the social and environmental burden, opening up new directions for further promoting the comprehensive recycling and utilization of hazardous waste materials.

[0031] The present invention has been described in detail above through specific and preferred embodiments. However, those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for enriching indium and tin metals from complex hazardous waste materials, characterized in that, Includes the following steps: (1) Detection of indium and tin in materials: Analyze and test the content of indium, tin and other valuable metals in the antimony-containing hazardous waste materials; (2) Slag-mixing type: Based on the test and analysis results of antimony-containing hazardous waste materials, iron, silicon and calcium are added to the antimony-containing hazardous waste materials to obtain a mixture. The grade range of various elements in the mixture is as follows: Fe / SiO2=1.1~1.4, CaO / SiO2=0.5~0.7; (3) Control the oxygen-carbon ratio: Calculate the required amount of pulverized coal based on the metal content of the material fed into the furnace and the heat required for melting, and then deduce the amount of oxygen to ensure a reducing atmosphere in the mixture fed into the furnace. The oxygen-carbon ratio is controlled between 0.4 and 1.8 Nm. 3 Within the range of / kg, the specific adjustment is based on the three stages of feeding, reduction, and slag discharge in the operation cycle. The reduction time and slag discharge time of the side-blown reduction furnace can be extended or shortened according to the furnace conditions. (4) Control the liquid level height: The height of the molten liquid in the reduction furnace is controlled at 1.5 to 1.8 m to reduce the ash rate and improve the enrichment efficiency of indium and tin metals; (5) Heating and melting: After the mixed material is put into the furnace, it is heated by the heat of pulverized coal combustion under oxygen-rich conditions, raising the temperature to 1200-1300℃; (6) Reduction smelting: When the furnace temperature rises to the predetermined temperature, the oxygen-carbon ratio of the reduction furnace is changed and the molten metal in the reduction furnace enters the reduction period; high-level smelting is carried out under the strong reducing atmosphere generated by the pulverized coal in the reduction furnace to produce lead-antimony alloy, enriching tin in the alloy and indium in the flue ash. The time intervals for the three stages of feeding, reduction, and slag discharge in step (3) are 40–50 min, 40–50 min, and 10–20 min, respectively, and the corresponding oxygen-to-carbon ratios for the three stages are 1.45–1.5 Nm. 3 / kg, 0.4~0.5Nm 3 / kg, 0.8~0.9Nm 3 / kg.

2. The method for enriching indium and tin metals from complex hazardous waste materials according to claim 1, characterized in that, The indium, tin and valuable metal contents in the material in step (1) are 0.01% to 0.2%, 0.3% to 0.8% and 30% to 45%, respectively.

3. A method for enriching indium and tin metals from complex hazardous waste materials according to claim 1, characterized in that, The iron, silicon, and calcium contents in the mixture in step (2) are 26%–28% Fe, 23%–26% SiO2, and 11%–13% CaO, respectively.

4. The method for enriching indium and tin metals from complex hazardous waste materials according to claim 1, characterized in that, In step (3), the material is smelted in the furnace under oxygen-enriched conditions, and the following reaction occurs during the smelting process: Oxidation reactions: 2C + O₂ = CO 2CO + O₂ = CO₂ Main reduction reactions: PbO + C = Pb + CO PbO + CO = Pb + CO2 Sb2O3+CO=2Sb+CO2 2Sb2O3+3C=4Sb+3CO2 Sb₂O₃ + 3C = 2Sb + 3CO SnO₂ + 2C = Sn + 2CO (SnO₂ + C = Sn + CO₂) SnO₂ + 2CO = Sn + 2CO₂ InS2 + 3O2 = InO2 + 2SO2.

Images