Study On Preparation And Energy Saving Effect Of Self-insulation Block With Phosphate Tailings

With China's economy developing rapidly,energy consumption is increasing.In the total energy consumption of the whole society,the proportion of building energy consumption is very large,so building energy saving is particularly important.A large number of resources have been consumed,while a large number of solid waste was produced,such as phosphate tailings.In our country,a large number of phosphate tailings are produced every year.Because of years of accumulation,it can not be used effectively,which has caused serious harm to the surrounding ecological environment.With the "green building" concept,green building materials are becoming more and more popular.Using phosphate tailings to make green building materials can not only consume a large amount of industrial solid waste,protect the ecological environment,but also bring some economic benefits.To prepare the blocks which meet the requirements of thermal performance,this paper established the effective thermal conductivity calculation model based on series model and parallel model,compared the effect on the thermal conductivity of materials between solid skeleton thermal conductivity and porosity through the single factor sensitivity analysis method.The results showed that the influence of porosity on the thermal conductivity of materials is greater than solid skeleton thermal conductivity,when changing their value from-20% to 20%.This conclusion has guiding significance to the experimental design.The experimental method is determined,after the analysis of the performance of raw materials.Adding 30% ? 40% ? 50% phosphate tailings were used to adjust the thermal conductivity of the skeleton.Mixed with 10~30g foam,followed by an increase of 2.5g to adjust the porosity of the block.The test results show that the thermal conductivity of the solid skeleton decreases with the increase of phosphate tailings;with the increase of foam volume,the porosity increases,the average pore diameter of the pores in the block increases,and the thermal conductivity of the block decreases;When the doping amount of phosphate tailings is 50%,the porosity is greater than or equal to 45%,the thermal conductivity of block is less than 0.2 W/(m?K).After optimization of preparation parameters,B07 grade block was prepared,its thermal conductivity is 0.15 W/(m?K),its strength grade is A3.5,which meets the requirements of exterior wall brick strength.Taking the building in hot summer and cold winter zone as an example,the influence of the self insulation block with phosphate tailings on the heat insulation and the condensation on the surface of the wall is analyzed.When applied to the building envelope,the calculated surface maximum temperature of the self insulation block with phosphate tailings in summer is 36.79? less than the surface maximum temperature of aerated concrete wall which is 37.03?;the calculated temperature of thermal bridges is 16.62 ? greater than the temperature of thermal bridges of aerated concrete wall which is 16.24?.According to the calculation results of the DeST energy consumption simulation software,the energy saving rate of the self insulation block wall can reach 5.7% during air conditioning period,and the energy saving rate can reach 2.9% during the heating period.