Method for treating pyrite cinder by combining acidic leaching with alkaline dissolving

Abstract

The invention relates to a method for treating pyrite cinder by combining acidic leaching with alkaline dissolving. The method mainly comprises the following steps that: nitric acid is adopted to leach the pyrite cinder, so that alkaline oxide impurities containing sulfur and arsenic are desorbed, most of iron can still exist in a solid phase in the form of ferric oxide, and the iron is effectively enriched, wherein the iron enrichment ratio is more than 90%, the sulfur removal ratio is more than 98%, the arsenic removal ratio is more than 99%, the solid phase is acid-leached residue, and the liquid phase is acid-leached liquor; when the content of silicon dioxide is more than 15% and the total iron content can reach about 50% in the pyrite cinder, an alkaline dissolving treatment is needed, the alkaline-dissolved residue is iron ore concentrate, white carbon black is obtained after acidifying alkaline-dissolved liquor, and the liquid phase is a sodium chloride solution which can be used as a raw material of sodium hydroxide; the acid-leached liquor is added into ammonium dihydrogen phosphate to produce ferric phosphate which can be used as raw materials and ceramic raw materials of a lithium iron phosphate electromagnetic material; and purified acid-leached liquor is obtained after carrying out arsenic removal and can be applied to the production of nitro compound fertilizer. With the adoption of the method for treating the pyrite cinder by combining the acidic leaching with the alkaline dissolving, the pyrite cinder can be fully and comprehensively utilized, and thus, the resource utilization ratio is increased; and the energy-saving and emission-reduction effect is good, the method is beneficial to environment-friendliness, and the clean production in the acid making industry by using the pyrite cinder can be achieved.

Description

technical field [0001] The invention relates to a method for treating pyrite slag, in particular to a method for combined treatment of pyrite slag by acid leaching and alkali solution. It is mainly suitable for the treatment of slag produced in the process of producing sulfuric acid with pyrite as raw material, and the total iron grade in the slag is greater than 40%. At the same time, some technologies in the method can also be used for the treatment of red mud. Background technique [0002] Pyrite slag is the waste slag in the process of producing sulfuric acid from pyrite, and 0.8 tons of slag is discharged per ton of sulfuric acid produced, and the amount of slag is about 12 million tons per year. For a long time, the comprehensive utilization of pyrite slag has been an important issue concerned by the sulfuric acid industry. Pyrite slag is rich in iron resources, and the general grade is between 40% and 64%. At present, the utilization of pyrite slag is limited to the ...

AI Technical Summary

Problems solved by technology

Although our country began to conduct research on the comprehensive utilization of pyrite slag resources since the 1950s, and developed slag to make bricks, produce iron-based fine chemical products such as iron oxide red, and obtain high-grade slag through ore dressing or slag selection It is used as iron-making raw material and other processes, but most of these processes have problems such as large investment, low iron utilization rate, and easy to cause secondary pollution, and most of them are currently in a small-scale production state

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