Metallurgical waste treatment and utilization
Iron and steel enterprises aim at full utilization of solid waste and zero emissions, and most of them have made great progress. The combination of specialized centralized management and various management systems has also achieved initial results. At present, all steel companies have basically completed the full treatment and recycling of iron-containing resources in industrial solid waste. The basic sequence is: solid waste resource recovery → sintering → blast furnace → steelmaking → steel rolling, the so-called “large recycling model”. However, its utilization is still in the low-level, low-efficiency, low-value-added, low-level utilization, which is characterized by non-optimal economic and environmental benefits, such as the use of iron oxide scale, converter mud and gas mud, so it is developed in depth and The research on high-value utilization needs further research and development. This paper will explain the deep development of metallurgical waste from six aspects.
1. Strengthening the slag grade and quality of steel slag flux slag
The flux slag recovered after crushing magnetic separation of steel slag has been used by the sinter plant, and the ratio is generally about 115%. However, the blending of flux slag will affect the grade and quality of sinter, mainly because the water wetting property and pelleting performance of the steel slag are worse than that of iron ore powder. The amount of sinter plant is limited or even stopped, so that the flux slag utilization and export pressure Increase. Therefore, the experimental research on strengthening granulation of sinter and steel slag flux slag should be strengthened, and the suitable amount of steel slag flux slag should be discussed to ensure that the sintering speed, sinter strength, yield, utilization coefficient and sinter reductivity meet the requirements.
2. Further development of steel slag in cement production
Steel slag should be further strengthened for production test research and production verification of cement plants, and the optimal process control parameters for steel slag cement production should be explored to increase the amount of steel slag incorporation.
3. Development of steel slag powder production
The use of steel slag powder in cement and concrete is the best way to utilize high-value resources of steel slag in China. The steel slag with specific surface area of 400m2 /kg can replace 10%~30% of cement in equal amount, and can be directly used in concrete construction engineering, which can improve the late strength of concrete, improve wear resistance, frost resistance, corrosion resistance and cost. It is 30% lower than cement and can reduce the construction cost. It is the raw material for high performance and high durability concrete. At present, the annual output of steel slag powder has reached 3 million tons, and the products are mainly used for engineering construction. In the development of steel slag powder production, it is necessary to strengthen the selection of grinding equipment and the control of the grinding process.
4, steel slag for road materials and building materials
The key is to solve the problem of the stability of steel slag. It is necessary to improve the existing hot slag treatment process, and strengthen the technical research of steel slag hot slag treatment process and equipment. The research and development of the steel slag hot slag treatment and the hydraulic steel slag non-burning load-bearing bricks in Hunan’s Handan Iron and Steel Co., Ltd. achieved good results. Agrwal G and others at Alfred University in the United States use steel slag to produce CaO-rich glass-ceramics that are more resistant to corrosion and corrosion than ordinary glass.
5. Accelerate the development and utilization of gas mud
After the gas is re-elected, the carbon content in the tail mud is as high as 35%, and the carbon in the gas is recycled to replace the anthracite used in the blast furnace. Carbon powder can be recycled using a new recycling process.
6. Develop metallurgical dust sludge to produce coolant and slagging agent for steelmaking
The comprehensive utilization of converter mud, dust ash, iron oxide scale, etc. has always adopted the “recycling-processing-sintering utilization” process route, and is not a deep-developing and high-value utilization method of solid waste resources. The use of metallurgical dust sludge such as converter mud to produce coolants and slag-forming agents that meet the requirements of steelmaking, so that the utilization process of metallurgical dust sludge can be reused from the past “waste-burn-iron-steel” large-scale recycling to “waste-steel” small cycle. The use of transformations makes the system less energy-intensive, less polluting, less costly, and more profitable.
7. Pressing metallurgical waste into a stamping process
Generally, the high-pressure briquetting machine can extrude metal materials such as metal scraps, steel shavings, scrap steel, scrap iron, scrap copper, aluminum scrap, aluminum shavings, disassembled car shells, and waste oil drums into various shapes such as cubes and cylinders. Qualified charge. Easy to store, transport and recycle.