Process for co-producing sulfuric acid, fine iron powder and iron oxide red by ferrous sulfate heptahydrate and pyrite

Abstract

The invention provides a process for co-producing sulfuric acid, fine iron powder and iron oxide red by ferrous sulfate heptahydrate and pyrite and relates to the process technology of resource utilization of titanium dioxide byproduct solid waste ferrous sulfate. The process comprises the following steps: adopting titanium dioxide byproduct ferrous sulfate heptahydrate and pyrite as raw materials; increasing the mixing amount of the ferrous sulfate heptahydrate as much as possible through transforming the ferrous sulfate heptahydrate into ferrous sulfate monohydrate, oxygen-enriched roasting, preheating air in front of a furnace, controlling the sulfur content of the pyrite entering the furnace and the moisture and other technical means; and realizing the integrated co-production of the sulfuric acid, the fine iron powder and iron oxide red pigments through cinder fractionation, oxygen-enriched calcining and other process technologies. The process effectively improves the economic value of the heptahydrate ferrous sulfate and has an important significance on efficient and comprehensive utilization of the titanium dioxide byproduct solid waste ferrous sulfate heptahydrate.

Description

technical field [0001] The invention relates to a recovery and treatment process of ferrous sulfate heptahydrate, a by-product of titanium dioxide, specifically a process for co-producing sulfuric acid, iron concentrate powder and iron red by using ferrous sulfate heptahydrate and pyrite; it belongs to solid waste Comprehensive utilization of chemical technology field. Background technique [0002] The domestic annual output of titanium dioxide exceeds 1 million tons, and the by-product of sulfuric acid production of titanium dioxide exceeds 2 million tons. Ferrous sulfate heptahydrate, a by-product of titanium dioxide, contains a small amount of impurities such as aluminum sulfate and titanyl sulfate, and its purity is generally above 95%. Ferrous sulfate heptahydrate, a by-product produced by titanium dioxide manufacturers, is cheap, and the ex-factory price is generally around tens of yuan. Ferrous sulfate heptahydrate has an impact on the environment and cannot be stac...

AI Technical Summary

Problems solved by technology

Ferrous sulfate heptahydrate, a by-product of titanium dioxide manufacturers, is cheap, and the ex-factory price is generally around tens of yuan.

Ferrous sulfate heptahydrate has an impact on the environment and cannot be stacked at random. Long-term stacking will cause environmental pollution problems

[0005] 1. Ferrous sulfate heptahydrate is used as raw material for dry calcination to produce iron oxide red. The discharged calcination waste gas contains a large amount of sulfur dioxide and sulfur trioxide, which requires environmental protection; the decomposition of ferrous sulfate in the calcined product is not complete, and it needs to be dissolved in water again. Filtration and drying treatment increase the production cost; during the calcination process, the decomposition rate of ferrous sulfate is slow, and the quality of the formed iron oxide red is low

[0006] 2. Ferrous sulfate heptahydrate is used as raw material to produce iron oxide pigment series products by wet method. In the production process, caustic soda is used for neutralization, which requires a large amount of alkali, and the cost is significantly increased; neutralization with cheap ammonia water is used to form ammonium sulfate. Lime neutralization, dilute ammonia water is recycled and used, and calcium sulfate waste is formed at the same time, the process is also complicated, and the production process consumes a lot of energy

[0018] Ferrous sulfate heptahydrate is the raw material for preparing iron oxide red series pigments. Ferrous sulfate heptahydrate is used as raw material to finally prepare low-priced iron fine powder (the price is generally less than 700 yuan / ton), which is comparable to the production of iron oxide pigment products (the price is generally More than 2,000 yuan / ton), from an economic point of view, it is not very cost-effective

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