Study On The Preparation Process And Mechanism Of Non-Fired Brick By Using Iron Tailings

The emission load and deposit volume of iron tailings are very enormous. The iron tailings not only destory the environment, but also occupy large of farmland resources and bring potential safety hazard to people around of tailings pond. Preparing non-fired bricks by using iron tailings not only is a path of sustainable development to mine enterprise, but also implements the aim of build the environmental and resource-saving society.On the base of analyzing physical and chemical properties of iron tailings systematically, for example mineral composition, chemical component and particle size and so on, this paper had studied the process of component mixing and preparation process of non-fired brick. In this paper, the mechanism of materials blending and strength formation of non-fired brick had been studied by XRD, SEM etc dection means.The study results show that:(1) The main minerals of iron tailings are quartz, calcite and hematite, accompanied by a small amount of anorthose, dolomite. The granularity of iron ore tailings is fine, and proportion of particle size of less than 74μm accounted for 71.6%.(2) The optimization blending process of iron tailings, coal ash and cement is premix-roll grinding-mixing. The time of premix, roll grinding and mixing are 240 seconds, 100 seconds, 180 seconds respectively.(3) The optimum proportion by weight of using iron tailings to prepare non-fired bricks is iron tailings: cement: coal ash=82:10:8, dispersant is polycarboxylate superplasticizer with dosage 0.5% in cement and early strength agent is triethanolamine with dosage 0.06% in cement, molding pressure is 10 MPa, molding moisture is 16%, natural curing period is 28 days. The compressive strength, water absorption and soft property coefficient of iron tailings non-fired bricks are 23.28 MPa, 0.3% and 0.94 respectively, and meet the requirements of the MU15 of construction materials profession standard “Non-fired rubbish gangue brick”(JC/T422-2007).(4) Uniform mixture can’t be achieved through common stirring because of adhesion in iron tailings. Roll grinding can open the aggregates, reduce the internal porosity and improve the mixing uniformity of tailings, fly ash and cement. Roll grinding can improve the degree of mixing of materials, reduce the amount of cement required per unit area of the tailings, and decrease the thickness of the hydration product layer between the material layers within non-brick, so non-bricks that meet the requirements of standard could be prepared under the conditions of fine raw material and low cement content.Iron tailings are used to prepare non-fired brick, which is an efficient way to consume large amounts of iron tailings, meanwhile, it could save energy and reduce the carbon emission and have significance to environment protection. It is accord with the needs of China’s current stage of development of new wall materials that prepared non-fired brick by using iron tailings. Moreover, the investment of iron tailings non-fired bricks is low and can produce more economy income, has contribute to reduce the pressure of mine enterprise from encomy and society because of tailings stacked.