Innovative and Sustainable Development Strategy Implemented Technological Progress in Comprehensive Utilization of Iron and Steel Slag Promoted

摘要

China's iron and steel slag piled volume is about 300 million tons, which contains more than 6 million tons of metal Fe without being recovered. In 2002, another 53.89 million tons of new iron and steel slag was produced, with more than one million tons of metal Fe discharged together with slag. How to recover and utilize all metal Fe contained in slag is an important problem related with reducing energy consumption and costs in iron and steel enterprises. This paper gives & description of problems existing in iron and steel slag crushing, screening, magnetic separation and wet grinding plus magnetic separation technologies and discusses new equipment (self-colliding crusher) and technology for highly efficient recovery of metal Fe contained in iron and steel slag. New development in utilization of iron and steel slag as high-value resources is introduced; iron and steel slag powder being used as admixture of cement and concrete is the main way for iron and steel slag utilization in the 21~(st) century, another topic of this paper. Iron and steel slag powder in equivalent quantity being used to replace 20 percent approx 40 percent cement in concrete, thus blended and prepared concrete has improved strength, workability and durability. An analysis of iron and steel slag powder market is also given; high-efficiency low-energy-consumption iron and steel slag powder grinding equipment and technology are discussed for promotion of industrialization of large iron and steel powder production capacity. Shortcomings of concrete with blast furnace ore slag powder or steel slag powder being mixed alone are pointed out based on the analysis of compositions and properties of steel slag and blast furnace ore slag. It is stated for the first time that combined mixing of steel slag powder with granulated blast furnace ore slag powder into concrete is the optimum solution to guarantee construction quality. This has directive significance in development and application of iron and steel slag powder in China. Technical point of view described in this paper plays a guiding role in processing and utilization of iron and steel slag in iron and steel industry, and has realistic significance for realization of zero discharge of iron and steel slag, complete recovery of metal Fe contained in iron and steel slag and utilization of iron and steel slag as high-value resources.