Properties and Uses Industrial minerals

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Thursday, 27 August 2009 06:43

Article Index Properties and Uses Industrial minerals Properties and Uses Industrial minerals 2 All Pages Page 1 of 2 Properties and Uses Industrial minerals are essential to most industrial activities, being used as either raw materials or as processing aids. The industries in which they are used include paint, electronics, metal casting & foundry, paper, plastics, glass, ceramics, detergents, drugs & cosmetics, construction materials, to mention just a few. They are also employed as processing aids, and are increasingly important in environmental engineering. Paint Historically, fillers and extenders were used as a means of adding low cost bulk to paint solid content. Today, the range of extenders available is extremely wide and determines many of the paint's properties: gloss, opacity, flow, film toughness, permeability, rheology, resistance, etc. Water-borne systems, low solvent paints, powder coatings, high-solid coatings; industrial minerals and rocks are crucial to all these environment-friendly developments of paint technology. The main industrial minerals and rocks used in paint are: kaolin, calcium carbonate, talc, barite, etc. Electronics It is difficult to believe that the most elaborated computer is basically made up of stone. In particular, its nervous system is made of silicon, which is extracted from silica sand or massive quartz rocks. It is also quartz crystals that pace the functioning of most of today's clocks. After extraction, the silicon is delivered to the electronic manufacturers in the form of "wafers" a few centimeters wide. Tens or hundreds of processors and circuits will then be carved on each of them, through an optical process during which they are held in place in vessels of silica of the very highest purity. The expression "Carved in stone" has never been more apt as in the virtual world we live in today. Metal Casting & Foundry Very often in industrial processes, manufacturing relies not only on the principal component materials, but also on "processing aids" which make the fabrication of the finished product possible. One such example is in the foundry sector where casting is traditionally carried out in moulds made of silica and other industrial minerals and rocks. Metal casting is a major market for silica sand whose use goes back to the very beginning of the industrial revolution. Casting metal in sand has continued to be the cornerstone of many metal manufacturing processes and products. Other examples where IM are used as anti-sticking, polishing agents, etc. are endless. Paper The paper industry, particularly printing and writing paper, is by far the largest volume user of IM. The principal IM used in paper making are kaolin, talc, ground calcium carbonate, precipitated calcium carbonate and bentonite. Minerals are either used as fillers or as a coating on paper. Some, like talc, are also used in pitch control (absorption of wood resins that tend to obstruct the machines). The use of minerals in paper production increases the speed of the machine performance and fluidity in general. The final characteristics of the paper (strength, whiteness, glossiness, ink, retention, etc.) are largely determined by the blend of mineral used. IM are suspended in water before being incorporated into the process. The minerals are often supplied directly to the paper manufactures in a slurry form or even produced as an integrated part of the paper process (precipitated calcium carbonate). High quality, glossy paper is obtained by applying a thin layer of IM on the surface of the paper. As for fillers, the final characteristics of the coating and its fitness for use are governed by the nature of the mineral blend. To some extent, it could be said that we still write on stone tablets. Plastics & Polymers Polymeric resins are generally filled and/or reinforced with IM. For instance, it is talc and calcium carbonate that give their strength to plastic garden tables and chairs. Rigid PVC and PP are the two resins that account for the bulk of mineral consumption in plastics. IM are however also used in polyamide, unsaturated polyesters, HDPE and LDPE. Silicone,another of the polymers' family, has invaded our lives up to a point where one can hardly imagine what would be the situation without them. They are key in construction, aeronautic, medicine, packaging, etc. The raw material at the very basis of their synthesis is silica, an IM. Prev - Next >>

Last Updated on Thursday, 27 August 2009 21:55