Alternative for fine pure silica in kiln-casting glass molds

摘要

Silicon dioxide, also known as silica, is the most abundant mineral in the Earth's crust. Mixed with gypsum plaster, kaolin and water, they form the main components used in the composition of Kiln-casting glass molds. However, the silica used for these types of molds has very fine granulometry (37-74 mu m), which can lead to health problems and, in addition, it goes through purification processes, generating additional costs. Thus, aiming to propose a healthier and cheaper alternative for fine pure silica in molds composition, this work proposes the use of sea and river sand (300-700 mu m) in substitution of it. The raw materials and compositions used in this study were analyzed and tested by Optical Microscopy, X-ray Fluorescence, Scanning Electron Microscopy and Compression Tests. The compositions with fine pure silica and river sand proved to be more resistant, both before and after being subjected to a heat treatment. On the other hand, the composition with sea sand presented lower resistance, and this was regarded as a desirable feature for complex pieces, making easier their demolding. (C) 2019 Elsevier B.V. All rights reserved.