碳化养护钢渣制备建筑材料的研究进展

Steel slag is a kind of solid waste produced during the process of steelmaking, the emissionis huge, while the utilization rate is low in China. Huge amount of steel slag is produced caused which not only occupies land, but also causes environmental pollution and resource waste. In recent years, steel slag has been used as cement mixtures, concrete admixtures or coarse and fine aggregates in building materials to a certain extent. However, Both domestic and overseas researchers reported that the formation of Ca(OH)₂ and Mg(OH)₂ from free calcium oxide and magnesium oxide in steel slag by later hydration reaction will cause volume expansion, which resulting in poor stability of building materials containing steel slag. Solving the problem of poor stability of steel slag is the key point to large-scale development and utilization of steel slag resources. In recent years, many steel industry continuously develop steel slag pretreatment by optimizing smelting technology, forming a variety of steel slag treatment technology, improving the comprehensive utilization rate of steel slag, but different treatments of steel slag lead to different stability, uniformity, particle size and activity of steel slag. In addition to the traditional method of steel slag pretreatment to improve its stability, some researchers have proposed high temperature reconstruction method to eliminate free calcium oxide to promote its volume stability, but the process requirements are relatively high. Also some researches find that steel slag has shown high reactivity in CO₂-rich atmosphere, Preparation of construction materials via accelerated carbonation is a novel approach to recycle the steel slag. In this paper the current research progress on the carbonated steel slag construction materials was reviewed. The chemical and mineral compositions of steel slag, thermodynamic and kinetic of the accelerated carbonation reaction of steel slag were analyzed. The effects of mineral composition, particle size and gradation of steel slag, mix proportions of raw materials, pre-curing and initial casting pressure, moisture content, CO₂ concentration and pressure, carbonation temperature and time, on the composition, structure and properties of the carbonated steel slag building construction were comprehensively discussed. The improvement of carbonation on the steel slag construction materials and the relevant mechanism were discussed. Finally, based on the current research state and existing problems, some suggestions were put forward for the further study in and extending the application of the carbonated steel slag construction materials.