A method for thermally braising steel slag with low content of free calcium oxide

Abstract

The invention discloses a steel slag heat stewing method capable of reducing the content of free calcium oxide in steel slag. The steel slag heat stewing method comprises the steps that after smelting with a converter is finished, liquid steel slag is poured into a heat stewing tank; in a steel slag pouring process, nitrogen at the pressure range of 0.3-0.7MPa is used to carry out blowing on the steel slag, and large steel slag blocks are broken to be crushed by a mixing method; during steel slag pouring, the steel slag put in the heat stewing tank is subjected to initial water drilling slag wakening with the water drilling quantity of 3-5m<3> / h and the water drilling time of 1-5min / furnace slag, and after the heat stewing tank is loaded with the steel slag to 60-70% of the capacity of the heat stewing tank, the water drilling slag wakening is carried out with the water drilling quantity of 3-5m<3> / h and the water drilling time of 5-20min, so to allow the mean temperature of the steel slag in the heat stewing tank to be 850-1100 degrees; after the slag wakening is finished, a heat stewing tank cover is covered, and heat stewing water drilling is carried out with the water drilling quantity and the water drilling time controlled according to a control table, and after the heat stewing water drilling is finished, the steel slag are taken out of the heat stewing tank. With the adoption of the steel slag heat stewing method, the content of free calcium oxide in the steel slag can be reduced to below 3.0%, and the instability of the steel slag is eliminated, so that the performance indexes of the steel slag can meet the industry standards of cement, building materials and the like, the steel slag can be applied to the fields of steel slag powder production, building material products, project backfill materials, etc., and conditions are created for resource utilization of the steel slag.

Description

technical field [0001] The invention belongs to the technical field of steel slag thermal braising, and in particular relates to a method for thermal braising of steel slag with low content of free calcium oxide. Background technique [0002] Steel slag is a by-product of the steelmaking process. It is known as the number one waste slag in the metallurgical industry, and its annual emissions account for 16% of the country's total industrial emissions. The output of steel slag per ton of steel reaches 130-240kg / ton. In recent years, the annual domestic steel slag production is about 100 million tons. The new "Environmental Protection Law of the People's Republic of China" has been implemented since January 1, 2015. As a high-energy-consuming and high-pollution steel industry, the environmental protection pressure is extremely high. Among them, the harmless treatment and resource utilization of converter steel slag are more urgent. [0003] Due to the special conditions of co...

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Problems solved by technology

[0003] Due to the special conditions of converter smelting, the active components of steel slag are severely overburned, the content of free calcium oxide is high, easy to expand, poor volume stability, high hardness, and low activity, resulting in narrow application range of steel slag

In the traditional steel slag hot-simmering or hot-splashing treatment process, the free calcium oxide in steel slag is more than 3.0%, generally more than 4.5%, and the free calcium oxide index of steel slag cannot meet the requirements of the national standard GB / T20491-2006, so it is difficult to be used in concrete and cement and other building materials

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