| Steel slag as one of industrial waste took up large quantities of land resources, and caused water and air pollution. The recycling of steel slag can not only protect the environment, but also make use of natural resources effectively and promote utilization ratio of resources. The research purpose of this paper is to look for the reasonable method of reusing the steel slag comprehensively through the experiment, and then solve the pollution problem.In order to find a reasonable method of application, we must first understand the various properties of steel slag, especially the chemical composition, chemical properties and mineralogical composition. So before the experiment, relative testing on the slag must be conducted. By the determination it shows that iro,aluminum,silicon and calcium are the main elements which are mainly in the form of various minerals, such as calcium silicate(C2S),. tricalcium silicate(C3S), calcium silicate hydrate(CSH) and calcium hydroxide(CH), et al. These elements have some cementitious properties of hydration and can be used in building material industry.Because of its cementitious properties, steel slag can be used as clinker to prepare the steel slag cement. Cementitious properties of steel slag can be activated to a certain degree by gypsum. According to various indicators of cement, the proportion of each substance was determined. Compressive strength and flexural strength was tested in accordance with state Standard GB/T 17671-1999. The results showed that steel slag had hydrated to a certain degree. Its activity reduced significantly and the intensity is much less than the national standard. Therefore, using steel slag to produce slag cement is not feasible, we must look for some other ways.As the chemical composition of steel slag, it can be prepared for flocculant, but before that, iron and aluminum must be dissolved out. Referring to the literature, the best method was using hydrochloric acid. Then the influence of solid-liquid ratio, leaching temperature and leaching time on leaching rate was examined, and then the best leaching conditions was found, that was, under the condition of 60℃and 2h, adding 3 mol/L of hydrochloric acid to 1g slag, aluminum and iron leaching rate was the highest. Flocculant could be prepared after a certain degree of polymerization of silicic acid was added. Many flocculant performance parameters was studied, such as Si:(Fe+Al), curing polymerization temperature and polymerization pH value. Through single factor experiments and orthogonal test, the best polymerization process was found, namely Si:(Fe+Al) was 3 (molar ratio), polymerization temperature was 60℃, pH was 1.5 and polymerization reaction time was more than 2h.In water treatment, the dosage of flocculants and pH value of water sample are the main factors which affect flocculation. In order to search for the best condition, the experiment study using steel slag flocculant to process simulated wastewater and garlic wastewater respectively. The indicators turbidity and COD removal efficiency were studied. Results show the best dosage of flocculant (PAFCSi) is 120mg/L, pH range from 7.0 to 8.0, so it is a very economical water treatment agent.Turning waste into industrial products can achieve the purpose of using waste to treat environmental pollution, it is also a kind of economic and effective method which has great significance.
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