Evaluation of Calabash Chalk as Binder for Production of Foundry Cores

Abstract

Foundry researchers in developing countries like Nigeria are faced with the quest of finding new substitute input materials such as binding materials from locally available renewable sources to replace imported binders which are expensive. This quest has led to the findings of binding materials derived from yam, cassava, cereals and vegetable oil. However, these binders are obtained from foods and hence competing with their use for foundry work, which is of economic value to the country. This study focuses on using calabash chalk a non-edible substance as a binder for foundry practice. The study was carried out using calabash chalk as a binder together with Lamingo silica sand obtained from Lamingo dam in Plateau state, Nigeria. The sand was collected and analyzed in terms of grain size and clay content. The sand was then prepared to meet the basic requirement of a standard moulding foundry sand. By varying the binder and moisture content, cores were produced. The experimental investigation was focused on the mechanical properties of these cores. These include green compression, dry compression, and green shear strength, dry compression shear strength and permeability. Trial castings using aluminum alloy were made using cores made from 7% moisture content and 9% binder. The result obtained suggests that the calabash chalk material can be used as binder for non-ferrous metals.