BENEFICIATION OF IMPURE ZIRCON SAND FOR USE AS A HIGH QUALITY FACING MATERIAL IN FOUNDRY OPERATIONS

Abstract

Imported chromite sand had been used as facing material for high Mn-Steel castings in Delta Steel Company (D.S.C.) Foundry. These castings are very valuable high wear resistant products employed in various industries. In search for local alternative for the chromite sand, some zircon sand earlier imported for use in the Steel Melting Shop was tried and the result proved satisfactory. The trial was extended to unbeneficiated zircon sand from Vectics and Nigerian Mining Corporation, Jos. The latter trial revealed profused mould-metal reactions. The work reported here was aimed at examining the characteristics of locally available zircon and seeking means of adapting it as facing sand for high Mn-Steel casting without enormous capital investment on any beneficiation process. It is shown that unbeneficialed local zircon with grain size restriction between -0.25mm and +0.1mm has been found to produce castings with close dimensional tolerance and good surface finish and contain a minimum zirconia content of 60% - a result quite comparable with that obtainable using either chromite sand or imported zircon sand.