CHAPTER ONE
1.0   INTRODUCTION
1.1   Background of the Study
Foundry is a manufacturing process by which metallic products are formed by preparation of mould, melting the required metal, pouring it into a cavity formed by the mould and allow to solidify.  In this way the molten metal takes the shape of the cavity.  This product is cleaned and machined to desired dimension.  Moulds can be made of metals or non-metals but generally they are prepared in Sands.
(Oshungbure, 1998). Foundry Technology can also be described as the beginning and the end of Engineering.    Foundry Technology can best be described as underdeveloped in Nigeria.  Considering the fact that Technological development of a nation is anchored on the state of her foundry Technology.  Knowing the fact that machine component even for further production depends on the casting industry.
Thus, it can be rightly said that, the country is still in the development process.  Foundry Technology cannot be said to really make impact in Nigeria until the early part of the 1970’s when product of the industry were cast iron and non-ferrous material like aluminium.  Before this period, aluminium product was the prominent product and then very few cottage foundry workshop were around producing aluminum pots.
Foundry industries in Nigeria have moved from its traditional arm chair status to a more progressive, more customer emphatic and progress driven activity.
The major issues that would drive foundry industry in this country are globalization and Technology.  One common thread that runs through this issue is quality product for the customers is no doubt an imperative for the foundry industry to meet the current and future challenges.
(Howard, 1959), Sand used to make moulds must be carefully conditioned and controlled in order to give satisfactory and uniform results.  Ordinary Silica Zircon or Olivine are  compounded with additives to meets some requirements or alternatively Bentonite, Silica Sand and moisture with additives will also meets some requirements.
Refractoriness is provided by the basic nature of the sand, cohesiveness, bind or strength obtain by coating the sand grains with clay, such as Bentonite, Kaolite, illite that become cohesive when moistened.  Collapsibility is obtained by adding cereals or other organic materials that burn out when exposed to the hot metal thereby reducing the volume of solid bulk and decreasing the strength of the restraining sand.  Permeability is the ability of moulding sand to allow gasses to escape to atmosphere during pouring of molten metal into a well prepared mould.  Good moulding sand always represent a compromise between conflicting factors, such as grain size of the sand particles, the amount of bonding agents such as clay, moisture content and organic matters combined so as to obtain a satisfactory result.  Consequently some factors must be carefully controlled to assure satisfactory results.  Sand control is little concern to the designer of casting but, it is a matter of great concern to the foundry worker who expected to deliver casting of good and consistent quality.
In foundry practice, moulding mixtures of varied composition are used.  These multiple varieties result from the varieties in the nature of the castings and the quality of input materials.