Research On Low-cost Application Of Steel Slag In Constuction Matertals

Construction features of steel slag mainly depend on its chemical composition and formation process. Steel slag has the similar components with cement clinker, but the formation process of steel slag is different from cement clinker. The steel slag has low cementitious reactivity, poor volume stability, and bad grindability. All of these characteristics obstruct the large scale utilization of steel slag in the area of building materials.To avoid inherent defect of steel slag, and to increase steel slag utilization rate, the most effective way is to change the chemistry composition or process of the formation,that is to adopt the treatment methods from the source. So under the circumstances that the steel making process is unchangeable, only in the granulating of steel slag, the chemistry composition or process of the formation can be changed by adjusting component and technologcial conditions, this is the processing technic of process modification. The technic of process modification can take full advantage of the stee slag's heat energy and improve the quality and increase utilization rate of steel slag.The methods of process modification were adopted. After converter slag tapping, in the granulating of steel slag, through adjustment of chemistry composition to transform composition and structure of slag, the steel slag was improved to be high quality building materials with good grindability and volume stability in the case of keeping the good activity.This project researches the typical granulation treatment process of steel slag technique process of air quench treatment process and rotary cylinder treatment process and their corresponding physicochemical properties.The relationship among application performance, composition of mineral phase, composing component and treatment process was revealed from microscopic view. The determinants of steel slag performance is controlling of process parameters and adjustment of component.Through static modification in high-temperature furnace, high-temperature modification in IF furnace and high-temperature modification on field, comparison of several different modifier's effect of the modification, the fly ash is determined as the major constituent of modifying agent. At molten state, component of molten slag was adjusted. After cooling, slag was grinded by means of ball mill, analysising particle size distribution of modified slags by Screening Experiment; The content of free CaO was measured. The phase of modofocation steel slag was analyzed through the XRD and ore microscope. Effect and mechanism of action which improve the stability and grindability through high temperature ingredient modify was researched. With this method, the problems of instability and grindability were solved in process of steel slag application; Study of slag cementitious activity by Cement Mortar test.The results showes that,with this method,the problems of instability and grindability were solved in process of steel slag application, and also increases the activity of the steel slag.Makes it is possible for "large volume and low-cost"use of steel slags,so as to achieve the effect that "govern waste by waste ", comes about good economic benefits, conducive to the development of circular economy and achieves sustainable development, are of great significance.