Research On The Preparation And Properties Of Iron Tailings Aerated Concrete System

Aerated concrete is prepared by the process of adding, stirring, pouring, procuring, cutting, autoclaved curing etc. with the siliceous and calcareous materials as the main materials and addition of foaming agent. It is widely applied to building insulation engineering because of its advantages of low-density, high strength, thermal insulation, machinability etc. Besides, it becomes a new and good developmental prospect wall material.Iron tailings, waste after iron ore dressing, is the main composition of industrial solid wastes. The growth of iron tailings emission is faster and faster with the spurt development of iron and steel industry. Iron tailings, whose main component is siliceous material and content to 60%, can be used to prepare aerated concrete as the siliceous material.In this paper, the influence of compressive strength, dry density and coffined of thermal conductivity of aerated concrete were studied based on iron tailings as the main material, aluminum powder as the foaming agent and the certain thermal system. And the best mixture ratio is determined by orthogonal experiment design. The paper carried out the thermal regulation study at the optimal mixture ratio and determined the optimal autoclave curing condition. And it tested the performance of aerated concrete prepared at optimal mixture ratio and optimal autoclaved curing condition.Research result shows that when the amount of iron tailings changes from 58% to 64%, the compression strength of aerated concrete climbs up and then declines, and the dry density declines and then climbs up with the increase of the amount of iron tailings. When the amount of lime changes from 23% to 29%, the compression strength of aerated concrete climbs up and then declines, and the dry density declines and then climbs up with the increase of the amount of lime. When the amount of cement changes from 4% to 10%, the compression strength and dry density of aerated concrete climbs up and then declines with the increase of the amount of cement. When the amount of gypsum changes from 2% to 8%, the compression strength of aerated concrete climbs up and then declines, and the dry density declines and then climbs up with the increase of the amount of gypsum. When the amount of aluminum powder changes from 0.11% to 0.16%, the compression strength and dry density of aerated concrete climbs up and then declines with the increase of the amount of aluminum powder. The optimal mixture ratio is that the amount of iron tailings is 61%, lime is 27%, cement is 8%, gypsum is 4% and aluminum powder is 0.14% by orthogonal test.The dry density of aerated concrete is little changed, and the compressive strength increases slowly with the extension of heating-up time during the heating-up period. The dry density of aerated concrete decreases slowly, the compressive strength increases slowly with the extension of holding time during the holding period. The dry density of aerated concrete decreases, the compressive strength increases with the increase of constant temperature during the holding period. The dry density of aerated concrete and compressive strength increases with the extend of cooling time during the cooling period. The optimal autoclave curing condition is that heat 2 hours, hold 2 hours at 200 ℃, 1.4MPa and then cool 2 hours. Under conditions of the optimized mixture ratio and heat-treated system, the compressive strength of aerated concrete is 2.91 MPa, the dry density of aerated concrete is 520.11kg/m3, and the coefficient of thermal conductivity of aerated concrete is 0.078 W/m.K.