The 2011 Manufacturing & Process Innovation winner - ProWave

Vermiculite is one of those materials that few people have heard of, but which touches most of our lives in some way. A naturally occurring mineral mined mainly in South Africa, the US and China, it’s used extensively in fireproofing, brake linings, insulation and in many building materials for roofing and flooring. Its most familiar usage is in horticulture, especially for seed cultivation at both the industrial and domestic scale. It’s in hand warmers and the walls of AGA ovens, and used in glassblowing and bead making. It’s even used to incubate reptile eggs.

In its natural state, however, vermiculite is useless. The mineral, which is a form of clay, consists of many layers of mineral ’platelets’, packed close together. To make it useful, it has to undergo a process called exfoliation, which happens when it is heated. The mineral expands, forcing the platelets apart into a high-volume, low-weight configuration.

This process is extremely energy intensive, usually carried out in gas- or oil-fired furnaces. Around 600,000 tonnes of vermiculite is exfoliated per year, and the furnaces generally consume more than 1MWh of energy per tonne of material – and this is on top of the energy expended in mining the material in the first place. The amount of resources consumed, as well as the carbon emissions generated, are considerable.