Method and system for producing fine iron powder and co-producing sulfuric acid from ferrous sulfate monohydrate

Abstract

The invention discloses a method and a system for producing fine iron powder and co-producing sulfuric acid by using ferrous sulfate monohydrate, the raw material ferrous sulfate monohydrate enters a rotary kiln to rotate, heat transfer enhancement and mass transfer are also realized in the kiln, and pulverized coal is combusted by a combustor to provide heat for the rotary kiln; cold air exchanges heat with iron ore concentrate discharged from the rotary kiln in the cooler to recover heat and then enters the combustor to support combustion, and ferrous sulfate is heated, oxidized and decomposed in the rotary kiln to generate ferric oxide and sulfur trioxide flue gas; the method comprises the following steps: feeding sulfur trioxide flue gas into a sulfuric acid absorption tower, feeding sulfuric acid into the sulfuric acid absorption tower through a sulfuric acid absorption circulating pump, and absorbing the sulfur trioxide gas by the sulfuric acid in the sulfuric acid absorption tower to generate sulfuric acid. The iron resource in the sulfate process titanium dioxide byproduct low-value ferrous sulfate is used for producing high-quality fine iron powder, the sulfur resource is used for producing sulfuric acid, and the method has good economic and environment-friendly benefits.

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