Utilization potential of borogypsum and silica fume in producing lightweight building material

The present study is aimed at investigating the utilization of two crucial industrial wastes, borogypsum and silica fume, as the main raw materials in the production of building materials. For this aim, different receipts were designed from boron waste (borogypsum) belonging to Emet Boric Acid factory (Kütahya/Turkey) and silica fume, which was taken from Electrometallurgy facilities (Antalya/Turkey). Mixtures were prepared so that the amount of waste material used in the composition was 90%, and the remaining 10% was binder clay. The samples were prepared with different proportions of both wastes were pressed uniaxially at 10 MPa, and the shaped samples were then fired at 1000, 1050, 1100, and 1150 °C. Physical and mechanical tests, as well as mineralogical and microstructural analyses, were carried out on the fired samples. The technical properties of the samples derived from the wastes were evaluated depending on the type of waste material and its usage amounts, and firing temperatures. It has been understood that the use of high Borogypsum will cause high firing loss, which will negatively affect the dimensional stability of the material. Moreover, with silica fume addition to borogypsum, the water absorption and porosity values increased, and the strength values decreased accordingly. Consequently, the water absorption and bending strength values obtained in the samples prepared from a mixture of 70% borogypsum and 20% silica fume can be considered the usage as a wall tile is possible since they coincide with the technical properties defined in the EN ISO 10545-3 and EN ISO 10545-4 standards, respectively.