Low-temperature fused salt clean smelting method for tin

A low-temperature molten salt and molten salt technology, applied in the field of non-ferrous metal metallurgy, can solve the problems of air, land and water pollution, difficulty in separation of tin and iron, and difficulty in separation of tin and iron, and achieve the purpose of reducing temperature, promoting technological progress, and simplifying smelting. Effects of Tin Process

Inactive Publication Date: 2011-06-22
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to maintain such a high temperature, a large amount of high-quality coal or heavy oil must be consumed; at this high temperature, Cu, Pb, Bi, As, Sb, and Ag associated with tin are all reduced into crude tin, and As and Pb are also volatilized in large quantities, resulting in Severe pollution of surrounding air, land and water
[0005] (2) The separation of tin and iron is difficult, the process is long and the production cost is high
Because the thermodynamic properties of tin and iron oxides and their silicates are close, iron and tin are easy to form alloys, so a large amount of iron and tin are reduced together into coarse tin and hard ends, and SnO also forms slag with FeO in large quantities, resulting in slag High tin content, difficult tin-iron separation

Method used

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  • Low-temperature fused salt clean smelting method for tin

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] The chemical composition of tin concentrate A is (%): Sn 69.1%, As 0.01%, S 0.34%, Fe 1.12%, Cu0.07%, Pb 0.035%, SiO 22.17%. Weigh 100g of tin concentrate, 32g of pulverized coal, 310g of industrial grade sodium carbonate and 10g of industrial grade caustic soda and mix them evenly, and put the mixture into a graphite crucible. Push the graphite crucible into the resistance furnace, melt at 850°C for 2.5 hours, and produce 68.4g of crude tin containing 98.86% tin, and the direct yield of tin reaches 99.0%; the hot molten salt clarifies and separates the solid to obtain molten sodium 287g of salt and 35.6g of solid slag bonded with a small portion of sodium salt were leached with 200mL of tap water at a temperature of 75°C for 3 hours to obtain 19.7g of dry leaching residue, and the volume of the filtrate and washing liquid was 220mL. Into CO 2 , co-precipitating NaHCO 3 18.6g.

Embodiment 2

[0042] The chemical composition of tin concentrate B is (%): Sn 41.0%, As 1.6%, S 1.3%, Fe 22.3%, Cu 0.13%, Pb 4.5%, Bi0.11%, CaO 0.30%, SiO 2 4.12%. Weigh 100g of tin concentrate B, 26g of pulverized coal, 3.6g of zinc oxide, 300g of industrial grade sodium chloride and 15g of industrial grade caustic soda and mix evenly, and put the mixture into a graphite crucible. Push the graphite crucible into a resistance furnace, melt at 900°C for 2 hours, and produce 44.5g of crude tin containing 90% tin, and the direct yield of tin reaches 98.0%; hot molten salt clarifies and separates solids to obtain molten sodium salt 280g and 80g of solid slag bonded with a small portion of sodium salt were leached with 400mL of tap water at a temperature of 80°C for 3 hours to obtain 47.5g of dry leaching residue. The volume of the filtrate and washing liquid was 620mL, and CO 2 , co-precipitating NaHCO 3 28.2 g.

Embodiment 3

[0044] A kind of tin hydroxide slag produced by treating tin anode slime is used as raw material, the tin content is 60%, and it also contains a small amount of lead, antimony and sodium chloride; it is reduced with coke powder containing 82% C and 10% ash agent. Weigh 1000g of tin slag, 250g of coke powder and 1000g of industrial sodium carbonate and mix evenly respectively. After the mixture is loaded into a graphite crucible, 694g of molten sodium carbonate returned in Example 1 and Example 2 and 40g of NaHCO recovered are covered on the surface of the material . Then push the graphite crucible into the resistance furnace, melt at 800°C for 3 hours, and produce 612.4g of crude tin containing 96.5% Sn, and the direct yield of tin reaches 98.5%; the hot molten salt is filtered and separated by -200 mesh stainless steel mesh After the solid matter, 1510.6 g of molten sodium salt and 212 g of solid slag bonded with a small portion of sodium salt were obtained, and leached with...

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Abstract

The invention discloses a low-temperature fused salt clean smelting method for tin, which is to produce coarse tin by one step of placing tin concentrate or tin-containing material in sodium fused salt for low-temperature reduction smelting. The smelted product also comprises unreacted solid materials such as a gangue component and generated solid products. After the reaction is finished, a major part of inert fused salt separated from the solid materials is returned to a smelting process in a hot state, and the minor part of inert fused salt bonded with the solid materials is recycled after being treated by a wet process. The solid materials obtained after removing the fused slat by dissolving can be treated for recovering valuable metals. The method greatly lowers a tin smelting temperature, can produce coarse tin by one step, solve a tin-iron separation problem, shorten a process flow, reduce cost, greatly improve tin recovery rate and is a new low-carbon, clean and high-efficiency tin smelting method.

Description

[technical field] [0001] The invention relates to a low-temperature molten salt clean metallurgy method for tin, which belongs to the field of nonferrous metal metallurgy. [Background technique] [0002] Tin concentrate can be divided into three types according to the tin grade: high-grade concentrate (Sn>60%); tin medium ore (Sn: 30-60%); low-grade concentrate (Sn<30%). Existing tin smelting methods are divided into fire method and wet method; wet tin smelting process includes SnO2 reduction to metal tin-acid leaching-electrodeposition method, SnO2 reduction to metal tin-acid leaching-aluminum chip replacement method, SnO2 reduction to SnO Stable in the glass body-acid leaching-electrodeposition method and sodium sulfide+sodium hydroxide solution high-pressure leaching-electrodeposition method, etc., the above-mentioned wet tin smelting processes have large investment and high cost, especially a large amount of waste residue and waste water are produced, which are har...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B25/02
Inventor 唐谟堂杨建广唐朝波何静陈永明杨声海叶龙刚
Owner CENT SOUTH UNIV
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