Process for producing chromic anhydride and ferrous oxalate by taking ferrochrome as raw material

Abstract

A process for producing chromic anhydride and ferrous oxalate by taking ferrochrome as a raw material is characterized by comprising the following three stages: separating ferrous iron, namely reacting dilute sulphuric acid with ferrochrome powder, conducting heating for dissolving; adding oxalic acid into the obtained mixed solution of ferrous sulfate and chromium sulfate to prepare a mixed solution of ferrous oxalate, chromium sulfate and ammonium sulfate; separating trivalent chromium, specifically, carrying out stirring reaction on a mixed solution of chromium sulfate and ammonium sulfateobtained in the first stage and a dilute ammonia sulfate solution or water to generate chromium hydroxide; and preparing a chromic anhydride, specifically, mixing sodium carbonate, sodium chromate andsodium nitrate, conducting grinding to form powder to prepare a low-melting-point eutectic oxide, reacting chromium hydroxide generated in the second stage with the low-melting-point eutectic oxide at high temperature to obtain solid sodium chromate, dissolving the solid sodium chromate with boiling water, adding an acidic mother solution, regulating the pH value, then conducting evaporating andfiltering to obtain a sodium dichromate solution, and adding concentrated sulfuric acid into the sodium dichromate solution to obtain a chromic anhydride finished product.

Description

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AI Technical Summary

Benefits of technology

This patented technology prevents or controls environmental contamination without producing wastes through its use of special materials with good properties such as resistance against corrosion when exposed to certain substances like chrome salts. It also allows for efficient separation of reactions between different metals while reducing energy usage compared to traditional methods. Additionally, this new material can be used on various industries requiring higher levels of cleanliness due to better performance over previous processes. Overall, these technical improvements improve manufacturing economics, reduce emissions, enhance product qualities, increase profitability, promote sustainable development strategies, and make them more cost-effective overall.

Problems solved by technology

This patented technical problem addressed in this patent relates to improving the quality and efficiency of manufacturing processes involving different types of metallurgery products like those made up of stainless steel plugs, nickel plugs and platiniums. Current methods involve crushing crucibles called chloroferric acid, reducing them down through complicated procedures including grinding, dissolution, heat treatment, precipitation, filtering, drying, activation, coke making, hydrogen reduction, nitrox generation, polymerization, decomposition, purification, and others. Additionally, these existing solutions have issues associated with their environmental impact due to disposable sources of hazardous substances.