Method for treating blast furnace slag

Abstract

The invention relates to a method for treating blast furnace slag in a steel and iron plant. The method comprises the following steps of: mixing blast furnace slag melt and calcined lime in a storage tank provided with a heat exchanger; keeping the temperature in the storage tank between 1,200 and 1,295 DEG C; keeping the alkalinity R of the mixed materials between 2.0 and 2.1; performing sealing treatment on the storage tank till the mixed materials are completely pulverized; reclaiming waste heat in the storage tank through the heat exchanger; and taking out the pulverized materials from which the heat is reclaimed. Because water quenching treatment is not needed in the method, the water slag drying cost of a cement plant is saved, the problem of equipment abrasion during flushing the slag with water is avoided, and the operating environment and the quality of air are affected little; because large blast furnace slag granulating equipment is not needed, the energy consumption is low, the process is simple, and performance and additional value of the blast furnace slag are not affected; and the method is energy-saving and environment-friendly, is favorable for improving the comprehensive utilization level of resources, and has good economic and social benefits.

Description

technical field [0001] The invention relates to a method for treating blast furnace slag in iron and steel works. Specifically, it belongs to adding quicklime to high-temperature slag and utilizing 2CaO·SiO generated at high temperature 2 During the cooling process of the slag, crystal transformation and volume expansion occur, and the blast furnace slag is naturally pulverized to obtain granular blast furnace slag for cement production. Background technique [0002] Blast furnace slag is the main by-product in the iron and steel smelting process. About 300-350 kg of blast furnace slag is produced for every 1 ton of pig iron smelted. According to the calculation of my country's annual pig iron production of 563.16 million tons, the slag production amounted to 197.1 million tons. The slag discharge temperature of blast furnace slag is about 1450°C, and each ton of slag contains heat equivalent to 60kg of standard coal. Therefore, doing a good job in the treatment of blast f...

AI Technical Summary

Problems solved by technology

The water flushing slag method cannot fundamentally change the process characteristics of water consumption of granulated slag, the physical heat of the slag is basically lost, and the SO 2 、H 2 The discharge of pollutants such as S not only affects the working environment but also pollutes the air.

[0004] In terms of waste heat recovery from blast furnace slag, the recovery and utilization of waste heat from water flushing slag in China is limited to heating with waste heat from slag flushing water, and the recovery rate of waste heat is low, only about 10%.

The slag heat recovery methods currently being developed mainly include medium heat exchange method and chemical reaction method, but the technology is not yet mature, some have low efficiency, some affect the performance of blast furnace slag and reduce added value, and some have large investment in equipment, etc.

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