Minerals, as fillers

Apparently, none of WPC manufacturers adds calcium carbonate as a filler in then-products. LDl Composites, which use Biodac that consists of about 25% CaC03 and 25% of kaolin (clay), also did not use individual minerals as fillers. Nevertheless, there are many publications, mainly by suppliers of minerals and university researchers, describing benefits of calcium carbonate in WPCs. 

The use of minerals as fillers in polymer materials was extensively employed until the late 1970s aiming to reduce final costs, since these fillers are heavier and cheaper than the polymers that had been used. As there was a vertiginous increase in petroleum prices during and after the 1973 and 1979 crises, in addition to the introduction of polypropylene on a commercial scale and the development of new materials containing mica, glass spheres and fibers, talc, and calcium carbonate, the ceramic raw material market as fillers was expanded and research regarding the interaction between... 

Griffiths, J.B., 1990, Minerals as Fillers - Modification to Serve Modem Markets , Plastics and Rubber Processing and Applications, Vol. 13, No. 1, pp 3-8 Griffiths, J.B., 1987, Surface Modified Minerals , Industrial Minerals, Oct., pp 23-45 Joslyn, W., 1986, Optimal Pretreatment of Reinforcement Modifiers with New Generation Silanes , C.H. Kline Company Conference on Chemically Modified Minerals, October 9, 1986... 

In order for thermoplastics to be molded into useful articles, they must first be plasticated, i.e. melted, and then held in the mold until resolidified. For ease of handling and to avoid excessive air entrapment, thermoplastics are usually supplied as cylindrical pellets about 1/8 inch in diameter and 1/8 to 1/4 inch in length. Powdered polymers are used in the processing of PVC and in rotational molding. The incorporation of minerals as fillers and remforcements creates certain problems, since they are much harder and... 

In recent years, synthetic polymeric pigments have been promoted as fillers for paper. Pigments that ate based on polystyrene [9003-53-6] latexes and on highly cross-linked urea—formaldehyde resins have been evaluated for this appHcation. These synthetic pigments are less dense than mineral fillers and could be used to produce lightweight grades of paper, but their use has been limited in the United States. 

Asbestos It is not the name of a distinct mineral species but is a commercial term applied to fibrous varieties of several silicate minerals such as amosite and crocido-lite. These extremely fine fibers are useful as fillers and/or reinforcements in plastics. Property performances include withstanding wear and high temperatures, chemical resistance, and strengths with high modulus of elasticity. When not properly handled or used, like other fibrous materials, they can be hazardous. 

A schematic flow chart of the beneficiation options that are currently in practice is shown in Fig. 7. These processing schemes are primarily employed for the production of pozzolan, but other products may result, such as carbon fuel and mineral grade filler. The fly ash beneficiation option applicable to a specific site is dependent on many factors, but the primary consideration is whether the fly ash is wet or dry. Once ash has been wetted, flotation is the only practical beneficiation option. It may be technically feasible to use thermal processes on damp ash, but the amount of heat required will be significantly increased, thus decreasing the economic value... 

Clay minerals are widely used in the filler industry and the production of the various types has been described by Hancock and Rothon [85]. The products available range from unaltered kaolin to products produced by calcination. Kaolin deposits are widespread throughout the world. While simple clay minerals are extensively used as fillers in elastomers, their use in thermoplastics is more restricted and the principal products used are those obtained by calcination of ka-olinite. Thus metakaolinite finds application in PVC and silane treated calcined clay in polyamides. The production of these forms only is discussed below. 

Rubber is vulcanised by treatment with sulphur chloride or by heating with sulphur. In most cases, however, rubber articles are made, not of pure vulcanised rubber, but of the latter mixed with various other substances, organic and inorganic. The organic substances more commonly used are brown and white factis, fatty oils, oxidised oils, waxes, mineral oils, paraffin wax or ceresine, resin or resin oils, bitumens, tar, pitch, starch, and artificial dyes. Very many inorganic compounds may be added either as fillers or to give colour, e.g., talc, kaolin, asbestos, chalk, gypsum, lime. 

Despite their overawing complexity, clay minerals are to receive particular emphasis in this book as model systems. They are of high abundance and of key importance in sedimentary and soil systems (63-64), as ceramic materials (65) and as industrial fillers (66) they exhibit essentially all of the generic spectroscopic and surface chemical properties of reactive minerals in general and there are good reasons to believe that many of the spectroscopic and chemical attributes of minerals as a whole may be exaggerated in clays. 

X-ray Diffraction Analysis. The inorganic components of paper are the most suitable ones for quantitative X-ray diffraction analysis. Most of these compounds are minerals and are present as fillers, coatings and pigments (often whiteners) which are added to improve the properties of the paper. Examples of compounds commonly added to paper are alumina, aluminum silicate, barium sulfate, calcium carbonate, calcium sulfate, calcium sul-foaluminate, iron oxide, magnesium silicate, silica, titanium dioxide, zinc oxide, and zinc sulfide (28). Some of these, e.g., calcium carbonate and titanium dioxide, may be present in any of... 

As noted earlier, a great variety of additives and fillers may be used in plastic compositions. A recent review report about fillers lists common minerals as... 

Clays are minerals produced by the weathering action of water and heat on primary minerals. Their compositions can vary widely as a result of the replacement of one element with another. Invariably, they are microcrystalline or powdered in form and are usually hydrated. Often, they are used as supports for catalysts, as fillers in paint, and as ion-exchange vehicles. The clays that readily absorb water and swell are used as lubricants and bore-hole sealers in the drilling of oil wells. 

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