Method for mixed slag smelting reduction recycling and thermal refining

Abstract

The invention discloses a method for mixed slag smelting reduction recycling and thermal refining, and belongs to the field of non-blast furnace iron making and comprehensive utilization of resources. With the method, pig iron or steel and a phosphorus-rich phase are recycled from mixed slag, and slag thermal refining is carried out. The method comprises the following steps that (1) blast furnace slag and molten steel slag are mixed; (2) gas blowing is carried out to carry out smelting reduction; and (3) separation and recycling are carried out. According to the method, blast furnace slag and the molten steel slag are mixed, then, oxidizing gas is blown to carry out molten reduction iron making, the iron in the mixed slag is recycled, phosphorus-rich phase recycling and slag thermal refining are achieved, and the reduced slag can serve as slag cement or a cement regulator or an additive in cement production or cement clinker, or be used for producing high-value-added cement clinker. The method for mixed slag smelting reduction recycling and thermal refining is short in reaction time, high in metal recycling rate, low in production cost, high in material adaptability, high in handling capacity, friendly to the environment, high in economic benefit, and capable of effectively achieving the purpose of high-efficiency recycling of metallurgical resources and thermal energy, and is a new smelting reduction technology.

Description

technical field [0001] The invention belongs to the fields of non-blast furnace ironmaking and resource comprehensive utilization, and in particular relates to a method for smelting reduction recovery and quenching and tempering treatment of mixed slag. Background technique [0002] As we all know, my country is the country with the largest steel output in the world. In 2015, the output of pig iron exceeded 700 million tons, and the output of crude steel exceeded 900 million tons. Ironmaking, steelmaking, and ferroalloy production are important process units of iron and steel production. Iron and steel metallurgical slag, such as blast furnace slag, steel slag, and ferroalloy slag, are produced during the production process. More than 400 million tons. [0003] Blast furnace slag is produced during the blast furnace reduction process. It not only contains reducing substances, such as coke, coal powder, carbon, carbon powder, etc., but also contains high content of CaO, SiO ...

AI Technical Summary

Problems solved by technology

Although steel slag can be utilized in the above-mentioned way, it is still subject to many limitations: (1) free CaO and MgO reduce the stability of steel slag volume; (2) higher content of iron oxide increases the difficulty of grinding; (3) When steel slag is directly returned to the metallurgical process for reuse, phosphorus will gradually be enriched in iron, which limits the application of steel slag; (4) steel slag is easy to pulverize; (5) fluorine and heavy metals may be leached by rainwater to pollute the environment

At present, the utilization rate of steel slag is only 20%, resulting in a large accumulation of steel slag, which pollutes the environment and wastes resources

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