Study On Preparation And Properties Of Chlorite-quartz Schist For Cement

China is a country of rich in mineral resources.People in the mining resources and promote economic and social development at the same time also produced a large number of temporary difficult to use mining waste rock.Waste rock is disposed of in piles and landfills,and causes serious ecological pollution.Chlorite-quartz schist is a kind of mining waste rock with a huge amount of rock discharge,and its chemical composition is similar to that of cement silica-aluminous raw materials.If chlorite-quartz schist is substituted for cement silica-alumina raw materials to prepare silicate cement,it can not only achieve the effect of solid waste utilization,but also alleviate the problem of decreasing traditional cement silica-alumina raw materials,and reduce the production cost of cement enterprises.For the characteristics of high silica and high magnesium of chlorite-quartz schist in Anshan area,the following experimental research and analysis were conducted for the preparation of silicate cement from chlorite-quartz schist:Firstly,the physicochemical properties of chlorite-quartz schist were studied based on the stratigraphic and geological characteristics of the Anshan area.The results show that the main chemical composition of chlorite-quartz schist is SiO₂ and Al₂O₃,the mineral composition is chlorite,quartz,calcite and black mica,the crystals in the minerals are mostly flakes,the structure is dense,the composition is stable,the average particle size is 31.06μm,the easy grinding is good,the radioactivity is qualified and easy to extract and use.Next,the rate value method was used for the formulation design of cement raw materials,and the effects of chlorite-quartz schist admixture,calcination temperature and cooling rate on the firing of cement clinker were explored;and the mineral composition,microscopic morphology and C₃S crystal type of cement clinker were analyzed in combination with visual and microscopic analysis.Finally,the physical properties such as compressive strength,flexural strength,standard consistency,setting time and stability of the silicate cement prepared from chlorite-quartz schist were studied experimentally,and the hydration and hardening mechanism of the cement was analyzed by combining XRD and SEM-EDS.The research results show that the early compressive strength of silicate cement prepared from chlorite-quartz schist is high and the later compressive strength grows slowly,with28d compressive strength of 47.8MPa and flexural strength of 7.4MPa,and all other performance indicators are in line with national standards.Each hydration product of the prepared silicate cement was as C-S-H gel,AFt,AFm and Ca（OH）₂,which did not differ from the cement of common ingredients,and the structure of the paste was relatively complete and dense,but a small amount of pore structure affected its later strength.