ASSESSMENT OF LOCAL CHROMITE SAND AS ‘GREEN’ REFRACTORY RAW MATERIALS FOR SAND CASTING APPLICATIONS IN A POST-PANDEMIC WORLD

Jonathan Kabasele,Didier Nyembwe

doi:10.7166/32-3-2615

Jonathan Kabasele, Didier Nyembwe

Open Access

https://doi.org/10.7166/32-3-2615

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Abstract

In a post-pandemic world, health and environmental safety will become a more important issue than it was before the COVID-19 pandemic. Several fields of engineering, including the foundry industry, have already adopted health and safety measures in the workplace. The risk of pulmonary disease caused by the inhalation of fine particles of silica sand, the main moulding material used in the foundry industry, is rampant in that industry. In terms of environmental protection, the new regulatory restrictions on the disposal of used sand create the need for moulding aggregates to be more recyclable than silica. Chromite sand is an alternative refractory sand for metal casting applications, and is abundant in South Africa. The present study investigated whether this aggregate has better overall reusability than silica. The focus of this study is on the use of chromite sand in foundries as a contribution to improving health in the workplace and to reducing the environmental impact of foundry sand.

Highlights

Metal casting makes use of either permanent or disposable moulds
The present study investigated whether this aggregate has better overall reusability than silica
Silica dust has been associated with respiratory diseases such as silicosis and tuberculosis

Summary

Introduction

Metal casting makes use of either permanent or disposable moulds. The sand casting method falls into the latter category. Foundry silica sand with a size distribution of between 50 and 60 AFS (220 to 250 microns) produces moulds with a good surface finish that requires low binder additions. Foundry-grade silica sand grains are round with a medium to low sphericity, which improves flowability, provides better permeability, and creates a strong mould with the addition of less binder [1]. Silicosis is dependent on the size of the silica particles. At a diameter of 100 microns, the particles can be inhaled, but are not small enough to reach the inner regions of the lung. At a diameter of five microns and less, silica fines become a real concern, as they are able to migrate to the deepest part of the lungs, causing scarring of pulmonary tissue.

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