The preparation method of Hunan
bismuth oxide
Process principle and process:
The treatment of high-grade bismuth concentrates is mostly smelted by pyro-method reverberatory furnaces. Bismuth concentrates are mixed with reducing agent coal powder, displacing agent iron filings, and group solvent soda ash, and then added to reverberatory furnace for mixing and smelting to produce slag and matte And crude bismuth, crude bismuth is refined to produce refined bismuth. China began to devote itself to the research of new technology of bismuth ore hydrometallurgy. Using FeCl3 as the leaching agent, leaching bismuth in the acid chloride system, so that the bismuth in the mineral enters the solution in the form of a bismuth chloride complex, and replaces it with iron powder to produce sponge bismuth, and produces refined bismuth through fire refining. The third tin smelter has built a wet workshop to process tin-bismuth mixed concentrate.
After the 21st century, many scientific research institutes in China focused on reducing operating costs, solving environmental pollution, regeneration of FeCl3 and enrichment of valuable metals in solution based on the different compositions and raw materials of bismuth ore. legal metallurgical process.
The main reagents and instruments
Hydrochloric acid (industrial pure), FeCl3 (chemical pure). Electric stirrer, 721 visible spectrophotometer, pH meter. The leaching agent is prepared from industrial hydrochloric acid, FeCl3, and distilled water in a specific ratio; the bismuth ore is ground in a mortar for 30 minutes, and the leaching is carried out in a 500mL beaker; the stirrer is a conventional electric stirrer.
The principle of leaching process
In hydrochloric acid solution, ferric chloride can oxidize the sulfur element of bismuthite in bismuth ore, so that Bi3+ can be transferred into the solution, and the sulfur element can be transformed into elemental sulfur. Adding hydrochloric acid can not only increase the leaching rate of bismuth, but also prevent the hydrolysis of bismuth trichloride in the solution. Bismuth ore is added to the leaching solution for reduction, so that the residual ferric chloride in the solution is reduced to divalent, and iron powder is added to the leaching solution to replace it to form bismuth sponge. The replaced solution is oxidized and regenerated by passing through chlorine gas.
Process flow
Weigh 20g of bismuth ore, grind it in a mortar for 30min, put it into a 500mL beaker, add the prepared leaching agent directly into the beaker according to the liquid-solid volume ratio of 3:1, stir with a stirrer, filter after a period of time, and filter the residue with Wash with 1.5mol/L hydrochloric acid solution for 2 to 3 times, take 1mL of leaching solution to prepare 250mL solution, and measure the concentration of Bi3+. Add quantitative iron powder to the rest of the filtrate to replace and precipitate to make bismuth sponge, and the filter residue is dried at a temperature of 100°C to measure the content of bismuth therein. The rest of the tailings are washed with water until neutral, and transferred to the copper-molybdenum separation process. Part of the waste water is discharged after being neutralized with lime.
