USE OF ZINC WASTE AS A CONSTRUCTION MATERIAL

Abstract

Jarosite is one of the byproducts of zinc extraction through hydrometallurgical process in zinc smelters. Owing to the presence of heavy metals (lead, sulphur, cadmium, copper and chromium) it has been categorized as hazardous waste under Schedule II, Ministry of Environment and Forest, 2008. Heavy metals not only affect human beings but contaminate air, water and soil resulting in acid mine drainage and acid sulphate soil. The presented work has tried to investigate physical and chemical properties of zinc waste (Jarosite) and to analyze its potential as a construction material. The presented work tried to establish physical properties such as specific gravity, shape and particle size distribution. Field Emission Scanning Electron Microscope (FESEM) has been used to assess the shape of Jarosite particles. LASER particle size analyzer CIS-100 has been used for finding the particle size distribution and it has been observed that Jarosite is fine enough for part replacement of cement. The chemical properties analyzed are pH, Chemical composition, Mineralogical analysis and Toxicity leaching characteristic. The X-ray fluorescence (XRF) has been used to obtain chemical composition of the Jarosite. X-ray diffraction has been used to analyze mineralogical composition. An attempt has been made to evaluate the characteristics of concrete when cement is partly replaced with Jarosite. The effect of Jarosite on mechanical properties like compressive strength, flexural strength and splitting tensile strength has been evaluated. Strength of concrete is found to increase up to 15% replacement. Effort has also made to investigate effect of Jarosite on durability of concrete when cement is partly replaced with Jarosite. Durability tests like acid attack, sulphate attack, rapid chloride penetration test and corrosion test has been performed. Performance of concrete containing Jarosite in marine environment and refractory structures also determined. Jarosite is not enhancing durability of concrete, it may be due to acidic nature of Jarosite and high percentage of sulphate and iron in Jarosite.