Development of Porous Tungsten Mud Waste-based Alkali-activated Foams with Low Thermal Conductivity

Abstract

Aim of this study was to produce alkali-activated foams with low thermal conductivity. Different precursors’ maximum particles sizes of 150μm, 300μm, and 500μm using a blend of 70% tungsten mining waste mud (TWM), 20% grounded waste glass (WG) and 10 % metakaolin (MK) with sodium silicate (SS) and sodium hydroxide (SH) as original material. Aluminium powder (Al) was used as a blowing agent and added first to the dry mix by changing content from 0.1g to 0.5g. Precursors and activators were mixed together to produce a homogeneous mixture, which was placed into a mould (100x200x60 mm3), and cured in the oven at 60∘C for 24 hours. The effect on foaming properties of different precursors maximum particles sizes were studied. The AAFs exhibited 28 day compressive strengths ranging from 2.28 to 16.1 MPa with the different densities from 913 to 1647 kg/m3 achieved through alteration of the foaming content. The thermal conductivity of AAFs was in the range 0.21– 0.33 W/m*K. Open celled hardened of the AAFs with 0.5g Al shows a high porosity of 58% with the mix made with 500μm. Therefore, tungsten mining waste-based alkali-activated foams shows a promise as thermal insulation material in some situations.