Process and Properties Study of Porous Thermal Insulation Building Materials Based on Walnut Shell

摘要

In this paper, shale and feldspar were regarded as matrix materials and silicon carbide was added as foaming agent. After a quality ratio of walnut shell was mixed with as pore-forming agent, porous insulation materialswere made through high temperature foaming. The firing curve was developed by studying the thermal history. XRD and micro-morphology were used to study the effects of the amount of walnut shell on the density, thermal conductivity and mechanical properties of the products. The results show that when the amount of walnut shell was 10%, the sample density was 180 kg/m~3, and the flexural strength and compressive strength could reach 1.031 MPa and 0.862 MPa respectively. Meanwhile, the thermal conductivity was 0.076 W/(m·K) and the water absorption could achieve 1.5%. It is concluded that adding walnut shell has no effect on the crystallization of the sample, but the walnut shell couldreplace a part of raw materials, resulting in the increase of density and strength. At the same time, the appearance of miscellaneous stomata could be attributed to the addition of walnut shell, and the number of open pores increased, leading to the increase of water absorption and thermal conductivity.