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Overview of using tailings to fire cement
Metal mine tailings discharged beneficiation plant is a finely divided, a large quantity of industrial waste, small particle size, and cement raw material particles come first. Therefore, it is of great significance to study and utilize the tailings mainly composed of calcite and quartz as the ingredients of cement raw materials.
The tailings produced by general metal mines are full-grain tailings, also known as raw-grade tailings. The so-called full-grain tailings refer to the tailings produced in the natural grading state that are produced from the mine selection plant and are not graded. When the mine sand is not filled in the mine, the full-size tailings are often graded. The tailings with a particle size of 30-37μ or more are called coarse-grained tailings, while the tailings with particle sizes below 30-37μ are called Fine-grained tailings.
Mines usually dump whole-scale tailings or fine-grained tailings in tailings ponds. Therefore, the study of these two types of tailings as raw materials for cement is of great significance for solving the problem of tailings storage and opening up new materials for building materials.
In 1966, Beijing Institute of Building Materials Science, Fankou Mine, Changsha Mining Research Institute, Changsha Nonferrous Metallurgy Design Institute, and former Beijing Cement Industry Design Institute conducted experimental research on Fankou tailings and achieved excellent results. , experimental research proves:
1. The whole-grade (or fine-grained) tailings containing suitable components can be fired into low-grade cement with good quality downhole cement filling. The strength of the product is up to 100-200 kg/cm for 28 days. Basically can meet the requirements of downhole cement filling.
2. After the tailings containing suitable components are calcined at a certain temperature, they can be used as a mixture of Portland cement, and the amount thereof can reach 15-55%. When 15% of tailings clinker is used as the mixed material, the cement label can still maintain 600; when 30% is mixed, the cement label can reach 500; when 50% is mixed, the cement label is 400. When the blending amount is 15 to 30%, the cement performance is good, and the coagulation and stability are normal.
3. Using the full-grain (or fine-grained) tailings containing suitable components, as the raw material of Portland cement instead of clay , can produce high quality tailings Portland cement with the number 400 or above. The cement has good performance, and the condensation and stability are normal.
The so-called tailings Portland cement refers to the clinker which is mixed with the appropriate amount of tailings and the appropriate amount of limestone , then burned to partial melting to obtain calcium silicate as the main component, and then added with appropriate amount of gypsum to form fine powder. A hydraulic cementitious material.