Research On Preparation And Property Of Aerated Concrete With High Content Of Copper Tailings

According to China's "Thirteen Five Year Plan" put forward to the urgent requirement to develop recycling economy,strengthening the comprehensive disposal and recycling of industrial solid waste,promoting the development of green building materials industry have being an important task in the current situation.In numerous beneficiation productions,non-ferrous tailings has damaging the ecological environment and even the whole society for its high production rate and the larger total stockpiling.Meanwhile,as a new energy-saving wall materials,aerated concrete not only has the characteristics of lightweight and insulation,but also a high absorptive capacity of solid waste.Therefore,there is good opportunity for the non-ferrous used for the preparation of aerated concrete,along with the recycling level and comprehensive benefits generated in it being improved obviously.In this paper,we take the copper tailings as research subjects for its most representative in the non-ferrous tailings,then it is used to prepare aerated concrete.Research is mainly focused on the influence of copper tailings's properties and content on the mix design and process parameters of aerated concrete.Besides,the property of the product,pore characteristics,compressive strength,volume density,water resistance and heat preservation,were also characterized.Studies have shown that the micro powder reactivity can be effectively improved when copper tailings mixed with river sand are grinding 20min,and the mechanical properties of B06 level aerated concrete prepared can better in line with the requirements of GB/T 11968-2006.Among them,The optimal formula is:copper tailings(CT-H)50%,river sand 10%,25%lime,cement 10%,5%gypsum,gas former 0.08%,sodium silicate 1.0%,stable foam agents 1.0%;And the optimal parameters:w/s 0.55,pouring temperature 55?,static curing temperature 50?,static time 4h,autoclave curing temperature 185?(1.1MPa),constant time 8h.By studying the porosity properties of aerated concrete with different level of density,concluded as follow:High volume density and uniform pore structure can improve the compressive strength;Large porosity,evenly distributed pores,more closed pores can improve the insulation performance;The higher porosity and the worse pore structure will result in an increase in bibulous rate,and then reduce its water resistance;The appropriate amount of foam stabilizer added to the process can optimize the stomatal structure,thus improving the overall performance of products.Microscopic test and analysis shown that,the main hydration products in the copper tailings aerated concrete copper are tobermorite,Al-tobermorite,CSH(B)phases with lower crystallinity and a large amount of amorphous gel,they intertwined with each other and combined the unreacted particles closely,constituting the hole-wall structure.Due to less active mineral content in the copper tailings,the amount of hydration products in the aerated concrete is insufficient with the increase of the copper tailings incorporated,which is harmful to form a better system of hydration products,then leading to the performance degradation of the product.