The Rational Treatment and Utilization of Blast Furnace Slag and Its Great Potential for Energy Conservation
Blast furnace slag (BFS) is a by-product obtained from iron and steel production. It is a non-metallic solid waste generated in the iron and steel industry, mainly from iron ore smelting and steel refining processes. In the production process of blast furnace, after the iron ore is smelting and steel refining by the high temperature of blast furnace, a lot of slag will be generated. The slag generated by the high temperature of blast furnace is called blast furnace slag. In general, the amount of slag generated by the iron and steel industry is about 4-5%, of which BFS accounts for more than 70%. With the rapid development of Chinas iron and steel industry, the output of blast furnace slag has been increasing steadily, which has brought serious environmental pollution and huge waste of resources.
BFS has characteristics of good liquidity, low melting point, low hardness and chemical stability, so it can be recycled and reused. Though BFS has low thermal conductivity and sound insulation effect, it also has chemical stability which is superior to other building materials. The utilization value of BFS has been more and more highly valued, and the recycling and utilization of BFS in the production process of iron and steel industry is playing an increasingly important role. The rational treatment and utilization of BFS can not only play the role of waste to energy, but also can improve the environment.
The technologies of BFS recovery and utilization include moistening, grinding and pre-magnetization. Among them, pre-magnetization is the common technique used in the steel industry. It is a technology that uses magnet to remove ferromagnetic material from BFS. After pre-magnetizing, BFS can be used in other industries, such as building materials and roadbeds. In addition, BFS can also be used to produce lightweight aggregate through crushing and sieving, and can be used in metallurgy, smelting, slag wool production during smelting, fertilizer and so on. For example, it can be used as raw material of grinding cement clinker with high-activity phosphorus partial electric flux, can also be used as steel slag agents, slag removers, cement agents and so on. The reuse and reuse of BFS can reduce the consumption of energy and materials, improve the utilization rate of resources, reduce production costs, reduce emissions, and finally provide a stable supply of high-quality materials for the development of national economy.
At the same time, utilization of BFS can greatly reduce the storage and landfill of waste slag. If treated properly, the produced slag can be used as daily resource to obtain more economic value. As a renewable resource construction material made from wasted materials produced by the iron and steel industry, BFS can basically replace other general industrial building materials, and its cost is lower than other building materials. Whats more, its highly recyclable feature can also save a lot of energy.
In modern society, with the advent of the carbon era, the low-carbon environmental protection of BFS treatment and utilization has become an urgent problem to be solved. It is an important way to realize the sustainable development of iron and steel industry with successive utilization of BFS itself. In the process of blast furnace slag treatment and utilization, the main tasks include: on the one hand, to reduce the total environmental stress of BFS disposal, on the other hand, to utilize the chemical composition of BFS effectively to obtain qualified and economically value-added products.
To this end, taking the comprehensive utilization of BFS as the starting point, it is necessary to establish perfect legal system, technical system and detailed implementation of other related systems. In addition, all relevant bodies should carry out necessary post-market surveillance and survey to ensure the safety of products made from BFS, so as to guarantee the normalization and healthy development of the industry.
In a word, BFS has great potential for rational treatment and utilization. Through the reasonable treatmeant and utilization of BFS, it can not only achieve the waste-to-energy purpose, but also reduce the pollution to the environment, which deserves further research and exploration.
