Method for preparing industrial ferrous sulfate and zinc sulfate by using pyrite cinders

Abstract

The invention provides a method for preparing industrial ferrous sulfate and zinc sulfate by using pyrite cinders. The method comprises the following steps of: fully reacting the pyrite cinders with excessive sulfuric acid, filtering to obtain a mixed solution I containing sulfuric acid, ferrous sulfuric, cuprous sulfate and zinc sulfate, and a lead-containing filter cake; adding an appropriate amount of ferrous hydroxide into the mixed solution I for neutralizing the excessive sulfuric acid; distilling the solution under a reduced pressure into a saturated ferrous sulfate solution, cooling the saturated ferrous sulfate solution to 25 DEG C until the ferrous sulfate is supersaturated, separating a large quantity of crystals out, and filtering to obtain a ferrous sulfate filter cake and a mixed solution II containing cuprous sulfate pentahydrate, zinc sulphate heptahydrate and a small amount of ferrous sulfates; washing, drying and smashing the ferrous sulfate filter cake to obtain a ferrous sulfate product; heating the mixed solution II to 30-40 DEG C, precipitating zinc sulfate in a form of zinc sulfate heptahydrate crystals, and filtering to obtain zinc sulfate heptahydrate crystals and a mixed solution III containing copper sulfate and ferrous sulfate; and washing, drying and smashing the zinc sulfate heptahydrate crystals to obtain a zinc sulfate crystal product.

Description

technical field [0001] The invention relates to the technical field of treatment and comprehensive utilization of three industrial wastes, in particular to a method for preparing industrial ferrous sulfate and zinc sulfate from pyrite slag. Background technique [0002] Pyrite ore slag is a waste residue discharged from the process of producing sulfuric acid by using pyrite or sulfur-containing tailings as raw materials. Its main components are Fe 55%-60%, FeO 3%-6%, SiO2 8.2% ~12.65%, SO 17%~0.76%, CuO 2%~0.427%, Pb 0.015%~0.045%, ZnO 0.03%~0.008%, and Au, Ag and other associated elements. [0003] Because pyrite slag contains a large amount of iron, it is generally used as a raw material for ironmaking. However, due to the low iron content, high sulfur content, silicon dioxide, and non-ferrous metals, especially in recent years, with the development of the sulfuric acid industry, the demand for pyrite has also increased. Pyrite is also used as a raw material for sulfuric...

AI Technical Summary

Problems solved by technology

However, due to the low iron content, high sulfur content, silicon dioxide, and non-ferrous metals, especially in recent years, with the development of the sulfuric acid industry, the demand for pyrite has also increased. Pyrite is also used as a raw material for sulfuric acid production, so the iron grade in the slag is correspondingly reduced. If it is still used for ironmaking, ideal economic results will not be obtained.