Detoxification method of chromium-containing slag entering metallurgical blast furnace by using coal spraying process form

Abstract

The invention provides a detoxification method of chromium-containing slag entering metallurgical blast furnace by using coal spraying process form. The method comprises the following steps: first drying and grinding the chromium-containing slag, then uniformly blending chromium-containing slag in an amount of 1 to 15 percent of the weight of coal powder into the coal powder, spraying the coal powder blended with the chromium-containing slag into a blast furnace cylinder from a blast furnace coal-spraying system, detoxifying the hexavalent chromium in the chromium-containing slag at the high temperature of the blast furnace under the reducing atmosphere, reducing the hexavalent chromium into trivalent chromium, and finally reducing the trivalent chromium into a chromium metal, wherein 92 to 98 percent of the chromium metal is melted into molten iron and 2 to 8 percent of the chromium metal enters the furnace slag; and meanwhile, reducing the iron oxide in the chromium-containing slag into iron metal for entering the molten iron. By utilizing the sealed blast furnace coal-spraying system to directly spray the chromium-containing slag into the blast furnace cylinder, the method has the advantages of few links, no pollution, thorough detoxification due to direct and full utilization of the high-temperature reducing atmosphere, full recycling and lowest cost compared with that of the conventional methods for treating chromium-containing slag.

Description

technical field

[0001] The invention belongs to the technical fields of iron and steel metallurgy and environmental protection. Background technique

[0002] At present, there are four methods for the harmless treatment of chromium slag: chemical method, physical / chemical method, melting method and solidification / stabilization method, among which the melting method is the most thorough. The melting method is a process of detoxifying hexavalent chromium by adding additives to toxic substances at high temperature. The smelting and harmless treatment technologies of chromium slag mainly include carbon reduction method, sintering method, dry reduction method and cyclone furnace sintering method. Although there are many existing methods, either the detoxification is incomplete, easily causing secondary pollution, or the cost is too high.

[0003] Chinese patent literature discloses a "method for realizing the harmless recycling of chromium slag by blast furnace ironmaking proce...

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