Study On Development And Properties Of Iron Ore Tailings Based Cementitious Materials

Filling mining method will be widely used in the future mining,which requires a large number of cemented filling materials.Cement is the best cementing agent,but the cost is high.In order to reduce the cost,the fly ash cementing agent has been successfully developed and applied at home and abroad.However,the lack of fly ash sources and the difficulty of collection have affected the preparation and application of fly ash cementing agent.In fact,mine tailings contain most of the components for preparing cementing agent.It is feasible to study tailings-based cementing agent,and it has more advantages.It not only has sufficient sources of mine tailings,but also can further reduce the manufacturing cost of cementing agent.It is also conducive to environmental protection and has practical significance.In view of the research on the development and properties of tailings-based cementitious materials,the composition of iron ore tailings was tested by using iron ore tailings of Angang as the main raw material,and the formula of iron ore tailings-based cementitious materials was formulated.The formula was with reference to the cement production process,and its cementing strength performance was measured to verify its effectiveness.The hydration products and microstructure of iron ore tailings-based cementitious materials were analyzed by XRD and SEM,and compared with cement,which further proved the effectiveness of the fired tailings-based cementitious materials.The following conclusions are drawn:The chemical composition of iron tailings was determined by XRF method.The results showed that the main components of iron tailings were Ca O,Si O₂,Al₂O₃and Fe₂O₃,which were similar to those of cement clinker:（1）Through the development of iron ore tailings-based cementitious materials,the preparation raw materials and preparation process of iron ore tailings-based cementitious materials were analyzed.According to the test results of the composition of iron ore tailings in a mine concentrator of Angang,the ratio of raw materials for preparing iron ore tailings-based cementitious materials was determined as iron ore tailings:limestone:bauxite:iron powder=21.2:73.8:2.69:2.31,and grinding and high temperature calcination tests were carried out with reference to the preparation process of Portland cement.（2）Through the research on the performance of iron ore tailings-based cementitious material,the influence of cement-sand ratio,slurry concentration and curing age on the strength of cemented filling body was analyzed.Under the condition of cement-sand ratio of 1:3 and slurry concentration of 74%,the compressive strength of iron ore tailings-based cementitious material filling body reaches 5.45MPa,which meets the requirements of mine filling strength.（3）Through the analysis of hydration mechanism of iron ore tailings-based cementitious materials,the hydration products and microstructure morphology of iron ore tailings-based cementitious materials and cement were analyzed by XRD and SEM,and compared with cement.It is concluded that the types of hydration products of iron ore tailings-based cementitious materials are more than cement,and the compactness of iron ore tailings-based cementitious materials is higher.