Process for preparing cement clinker additive from stainless steel pickling sludge

Abstract

The invention discloses a process for preparing a cement clinker additive from stainless steel pickling sludge, wherein the process comprises the following steps: S1, adding ferrous sulfate and liquidenvironment-friendly alkali into stainless steel pickling wastewater to obtain stainless steel pickling sludge; S2, adding fly ash into the stainless steel pickling sludge, uniformly mixing, and carrying out high-temperature dehydration treatment; S3, crushing and grinding the dewatered sludge into fine powder, adding 4%-6% of kaolin, uniformly mixing, and granulating; and S4, carrying out high-temperature calcination on the granulated material, and then crushing to obtain the clinker additive. According to the method, heavy metal ions in the pickling sludge generated in the stainless steel production process can be converted into harmless substances meeting the national environmental protection requirements; the content of metal Cr in the cement clinker obtained through the method is lower than 0.47%, the content of Ni in the cement clinker is lower than 0.06%, the quality of the cement clinker meets the index requirements of corresponding national product standards, reliability is high, and operation cost is low.

Description

technical field [0001] The invention belongs to the technical field of sludge resource utilization, and in particular relates to a production process of using stainless steel pickling sludge as a cement clinker additive. Background technique [0002] my country is a large stainless steel producing country, and a large amount of stainless steel products are produced every year. As a key link in the cold rolling process of stainless steel, it is necessary to dissolve the oxide film on the surface of stainless steel products (mainly composed of ferrous oxide) by pickling. (FeO), chromium oxide (Cr 2 o 3 ), manganese dioxide (MnO 2 ) and other components) and a chromium-free area layer to enhance the corrosion resistance of the stainless steel surface and produce a higher finish on the product surface. Commonly used pickling media include sulfuric acid, sodium sulfate, nitric acid + hydrofluoric acid, etc. The processing process is accompanied by the production of a large amo...

AI Technical Summary

Problems solved by technology

Generally speaking, the stainless steel pickling sludge produced by the pickling wastewater treated by the chemical precipitation method still contains certain pollutants such as nickel, chromium, and fluoride. Excessive amounts of heavy metals will have a great impact on the environment.