Method for preparing carbonyl iron powder in high-pressure circulating way

Abstract

The invention relates to a method for preparing carbonyl iron powder in a high-pressure circulating way, comprising the following steps of: carrying out synthetic reaction between a porous sponge iron material and carbon monoxide to generate pentacarbonyl iron and synthesized residue, enabling the synthesized residue to enter a recycling flow, freezing the pentacarbonyl iron, freezing and fine-filtering the separated reaction gas by a water freezing machine, conveying into a synthesis kettle by a circulation compressor and circulating, filtering and purifying the pentacarbonyl iron, and decomposing the pentacarbonyl iron into micrometer-grade carbonyl iron powder by vaporization and thermal decomposition. Compared with the general process, the high-pressure air circulation and synthesis technology improves the carbonylation ratio, greatly reduces the carbon monoxide consumption per ton of the carbonyl iron powder, shortens the synthesis period to 3 days, improves the productivity by 55 percent, improves the working environment and the labor intensity of personnel simultaneously and reduces the environment pollution.

Description

Technical field [0001] The invention relates to a method for preparing carbonyl iron powder through high-pressure circulation. Background technique [0002] Carbonyl iron powder is widely used in powder metallurgy mechanical parts, injection molding, high specific gravity alloys, information electronic magnetic materials, diamond catalysts, food and medicine and other fields. At present, the production process of carbonyl iron powder is mostly high-pressure gap and static synthesis production process. That is, porous sponge iron and carbon monoxide are statically synthesized under the pressure of 20-30MPa, the pressure of gas consumption is reduced, and after the reaction product carbonyl iron liquid is released, carbon monoxide is added again, and the operation is cyclic. The generated iron pentacarbonyl is condensed into liquid and separated from unreacted gas, and then thermally decomposed in the decomposition process to obtain carbonyl iron powder. Although this proces...

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Problems solved by technology

Although this process is mature and reliable, the fresh surface contact between gas and solid phase is slow, and the synthesized iron pentacarbonyl cannot be discharged in time, which will poison the synthesis reaction, resulting in low extraction rate of iron in raw materials, long synthesis period, and carryover in the synthesis residue. Problems such as carbonyl iron liquid, etc. have brought adverse effects on production safety and environmental protection

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