The Preparation And Performance Analysis For Aerated Concrete With Phosphate Tailings

With the increasing of population as well as the rapid development of economy, the contridiction between energy, resource and enviroment becoming more and more critical. Consequently, energy saving, emission reduction and the sustainable development become world most concerned hot topic now. Phosphorus tailings is a kind of industrial wast which is discharged by the phosphoric acid or phosphatic manure enterprise. It is difficult to effectively use. But when elder laid, it can not only cause pollution of the surrounding environment but also occupy a large amount of the land. Therefore, to effectively use the industrial waste and make it into energy-saving building materials, is worthy of discussion.Combining with the large amount of phosphate tailings which discharged in the actual production in Huangmailing Hubei Chemical Group, the physical characteristics of phosphate tailings was systematically studied in this paper, and took the other local raw materials into account, the process parameters of producing the aerated concrete with high content of phosphate tailings were also discussed. The main results are as follows:Firstly, the original of the phosphate tailings were fine, high moisture contenting and the SiO2 content was more than 60% in its main chemical ingredient, thereby, it's a very suitable raw material to produce the aerated concrete. At the normal temperature and pressure, the phosphate tailings had no activity while at the steam conditions pressure, the activity index reached 92.7% with 30% of phosphate tailings and 65.0% with 50% of phosphate tailings.Secondly, the mix ratio of producing the aerated concrete with the phosphate tailings was improved in the lab, the results showed that, with 6% of P.S32.5 cement, 65% of phosphate tailings,26.4% of lime,2.6% of gypsum,0.14% of Al powder(according to the amount of cementitious materials), the B600 level aerated concrete could be produced when the water-powder ratio was 0.64.Thirdly, according to the characteristics of phosphate tailing raw materials and the experience of the factory that producing the aerated concrete, the production parameters were designed as follows:the pressure increasing and heating phase lasted for 3h, the constant pressure and temperature phase lasted for 5h and the decreasing and cool phase lasted for 2h, so that the aerated concrete could have a better quality.Finally, the results of the microscopic analysis to the products showed the main hydration resultants of the aerated concrete with phosphate tailing were hydrated calcium silicate, tobermorite and hydrated garnet. The pore structure of the aerated concrete with phosphate tailing was uniform, dense, and fine structured.