Articles on the gypsum industry from Global Gypsum

Stockyards are used in the gypsum industry for storage of natural or synthetic gypsum and act as a buffer storage or mixing facilities for combining different gypsum sources before calcining. For new projects, operators must consider capital costs and the operational efficiency of equipment and must choose between the virtually infinite possibilities offered by the market. Homogenisers, blenders or storage only and circular or linear storage are the main decisions. This paper attempts to clarify this selection process, with particular attention to the specific properties of gypsum.

Higher thermal performance can be achieved by either installing more thermal insulation in a construction, or by using lower thermal conductivity insulation. This emphasis risks creating problems for constructions if other aspects of building codes are overlooked.

There is an opportunity for expressing the eco-thickness of architecture, but when development value puts a premium on floor space or storey heights, commercial attempts to make thinner walls and roofing are struggling with the uncertainties of product innovation. Foil-faced polyisocyanurate foams have not managed to achieve a lower than 0.021W/mK thermal conductivity. There is no full-fill polyisocyanurate foam product on the market and the reduction of air cavities in masonry walls from 50 to 25mm requires better workmanship.

Cavities behind rainscreen or ventilated coverings must be retained. Multifoil insulation products have received criticism and are now limited in their claims to performance. Silica aerogels are used in expensive internal dry-lining but cannot achieve a thermal conductivity below 0.013W/mK. It is increasingly recognised that only vacuum insulation panels (VIPs) can achieve lower than 0.005W/mK to offer the thinnest construction. Some VIPs promise thermal conductivities as low as 0.001W/mK.

Volker Schmitz from PCME Ltd reviews established methods of measuring dust concentration in industrial installations and highlights the benefits of PCME's electrodynamic techniques.

In the 1970s China began independent design and manufacture of gypsum wallboard production with a capacity of 4MM²/yr. In 1979 Beijing New Building Materials Company Ltd (BNBM) was established, pioneering the large-scale production of gypsum wallboard in China. It introduced the first modern, 20MM²/yr wallboard production line in the country and is now the market leader in China.

The process and chemistry of converting raw gypsum to a finished commercial board has been developed and refined over many years. Improvements to the process include improved board mixer and kiln designs as well as improvements to the chemistry both defined and non-defined by the process. Improvements have been achieved in terms of board-weight reduction, resistance to water and mould and specialised performance in areas such as fire-resistance and acoustical applications. The current process of wallboard manufacture has been refined to its current state with relatively incremental improvements to the technology with a significant focus on cost improvements exacerbated by the current economic environment.