RESEARCH OF N.Z. CLAYS VALUABLE TO INDUSTRIES

Bay of Plenty Beacon, Volume 14, Issue 45, 30 September 1949, Page 3

RESEARCH OF N.Z. CLAYS VALUABLE TO INDUSTRIES

Geologists and chemists work in close co-operation in the survey and research into the New Zealand resources of clays for industrial uses, and the development of rapid methods of analysis of clays has assisted these investigations. Different Requirements

Different industries have widely different requirements in the qualities of clays they use, and even amongst the fire-clays—“refractor-ies” that have to withstand very high temperatures—the range of requirements is still considerable. Not only must refractory clay be unaffected, by temperatures of at least 1,580 deg. C. (2,876 deg. F.), but some manufacturers require it to be also resistant to heavy pressures, or to physical wear, or to chemical action, or to violent changes in temperatures, and there are also demands for clays that have a combination of several of these qualities. x

The geologists of the Department of Scientific and Industrial Research have made widespread surveys of New Zealand deposits, and the samples of the borings made by them are tested and analysed by the chemists of the Dominion* Laboratory. These investigations ape also carried out in close collaboration with the Department’s Soil Bureau, with other Government Departments, and with the N.Z. Pottery and Ceramics Research Association (Inc.). Practical firing tests are made on various types of clays since their refractory qualities cannot always be inferred from analyses, but chemical analyses are afterwards made on those that have passed in the physical test in order to correlate composition v/ith physical behaviour. Building Up Data

A clay can be recognised and classified by its chemical analysis, and this has made possible the building up of considerable data on New Zealand clays. The rapid methods of analysis, which have been developed in the Dominion Laboratory, are of great assistance when large numbers *of samples of clays have to be tested.

Recently over fifty samples of clay from the North Auckland district were submitted to test. The samples were carefully collected by officers of the Geological Survey and the information obtained is a valuable contribution to the knowledge of the resources of refractory clays in that area.