Method of removing impurities in finished iron black produced with wastes and application of method

Abstract

The invention provides a method of removing impurities in finished iron black produced with wastes. The method includes: setting a three-stage offline washing high-pressure plate-frame filter press and a primary online washing high-pressure plate-frame filter press; setting a pulping trough and a buffer trough in each stage of offline washing so that full mixing of every stage of washing water andfinished iron black is facilitated, and washing effect is improved; passing the finished iron block through three-stage offline washing and primary online washing once in a forward feeding manner, and reversely feeding washing water to a washing system from an online washing terminal and reversely pass through every stage of offline washing system; allowing outflow of a clear water trough of thelast stage of offline washing system to enter an evaporative crystallization system so as to recycle industrially valued salts in the wastewater. The method helps improve the quality of finished ironblack, and may also combine with the evaporative crystallization technique to form industrial products with the principal salts in the wastewater via crystallization and separation, so that the salinewastewater problem is thoroughly solved.

Description

technical field [0001] The invention relates to the technical field of environmental protection waste recycling, in particular to a method for removing impurities in iron black products when using waste hydrochloric acid and waste iron sheets to produce iron black pigments. Background technique [0002] During the processing of metal products in the iron and steel industry, there will be a large amount of iron oxide scale on the surface of the metal product. In order to ensure the smooth progress of various subsequent processing procedures, the iron oxide scale on the surface of the metal product must be removed by pickling. In the pickling process, when the concentration of ferrous ions formed by the dissolved iron oxide in the acid solution accumulates to a certain level, the pickling solution cannot meet the process requirements and becomes a pickling waste solution, which is classified as a hazardous waste. Special handling is required. After the pickling of metal produ...

AI Technical Summary

Problems solved by technology

However, on the one hand, the traditional solution has undergone several stages of water washing, and the consumption of washing water is particularly large; on the other hand, the impurities removed from the washing contain a large amount of inorganic salts, which exceed the relevant national drainage standards, and need to be treated separately, which increases operating costs.

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