In the Centre of the Kempen, in the north of Belgium, Lommel is well known for the silver sand, quartz sand or witzand, a fine-grained, white, extremely pure sand with a low iron content that consists almost entirely of quartz (SiO2). There and in Mol and Maasmechelen this raw material for the glass making industry among others is found as a deposit of the Diestiaanse sea with massive kelp beds. The origin of the silver sand goes back to the Tertiary – the geological era between 70 million and 1 million years ago – in which several phases of transgression and regression of the sea occurred. In the last Ice Age – some 70,000 to 12,000 years ago - the Channel was formed that separates Great Britain from mainland Europe. When digging the channels in the region around Lommel, Mol and Dessel, in the mid of the 19^th century, people became aware of the commercial value of the white sand of the Campine.

Glass is a wondrous, diaphanous, crystalline material, transparent and translucent. As natural glass, it is as old as the world. See the coming article Natural Glass>

Durable too, as after a lifetime of re-use, it eventually decays back to grains of sand. In Lommel one finds also the flat glass from buildings and car windows – brought by ship – collected by the firm Maltha glass recycling and processed into new raw materials. Along with all the recycled glass packaging the re-use delivers a considerable saving in energy when it is re-melted. Glass (plural: glass) is a generic term for an indefinite number of substances of different compositions which are in a glassy state. Read the article in Techniques > Material Glass>  

Maltha is a leading processor of packaging and flat glass in Europe. Each year the firm processes more than 1 million tonnes of glass waste from companies, citizens and municipalities into high-quality new raw materials for use in making new products.

Glass mainly consists of silicon oxide, or sand, but melted sand alone would be unsuitable for glass manufacture, as above all, for the melting sodium (soda) and potassium (potash) which reduce the melting temperature, are needed as flux.

Glass is an amorphous material, not fluid and not solid; it has no solid crystalline structure. It is super-cooled matter in which the glass transition (transition) is made as it slowly cools. The addition of lime also makes the glass less prone to corrosion. By adding metal oxides one obtains the different colors and by adding minerals like magnesium, phosphorus and arsenic one obtains different glass types for specific purposes.

With increasingly complex recipes and chemical additives developed out of the ordinary glass and crystal glass, special glass types, composites and meta materials have appeared, such as the sprayable Nano-glass which is one of the most recent inventions.

Silver sand was used as an abrasive for cleaning household pots and pans, for scrubbing ships’ decks, and also to polish large mirror glass panes, and it is particularly suitable as a raw material for the glass industry. It makes up about 65% of the batch and is used in large quantities in this industry, for example for the production of cathode ray tubes but also as a raw material for enamel and porcelain, the chemical industry, in foundries and as raw material for heat-resistant materials. It is also used in detergents, abrasives and adhesives, paints, electronics components such as diodes, transistors and chips. 

The Sibelco company (founded as Sablières et Carrières Réunies in 1870) owns several Belgian and global concessions and is world market leader in the field of minerals and mining. In the centre of the former glass industry like in Lommel Philips had their glass balloon factory and a factory for machine-drawn lead glass and the glass factory (1910) of Stevensvennen produced bottles. The EMGO makes glass tubes and balloons at the plant by the joint venture of Philips and Osram. There was also a window glass factory Campinoise, which has been closed now, while the corresponding district with houses at Lommel-Glasfabriek in 2008 was cleared and scrapped due to the cadmium pollution caused by the zinc factory. 

Since 2007 the Glazenhuis, glass museum and work shop, is in the very centre of the city of Lommel and in the afternoon, after visiting the collection as donation of the private glass collection Embrechts-Ryckaert, the society went to visit the exposition Body Talk.
 
The book Building on sand written by Jean-Louis Moreauis was released by SCR (Sablières et Carrières Réunies)/Sibelco, wwwsibelco.com and gives a wonderful account of the history and future of the factory, the sand, mining, the glass industry, the landscape and its social, politic and environmental impact. With graphic material, letters, photos and maps it explains clearly why modern life could not be developed without the silver sand of Sibelco.

Correction Article: Christine Andersen, DK