The main raw materials

Each mineral raw material has a specific influence on the rheology of the paste, the development of the microstmctme, the phases formation during the heat treatment and the properties of the finished product. The manufacture of all silicate ceramics requires such a large number of raw materials, which cannot be discussed here. Only those most commonly used, i.e. clays, feldspars and silica, will therefore be described. 

All clays do not exhibit the same aptitude towards manipulation and behavior during firing. Ceramists distinguish vitrifying plastic clays, refractory plastic clays, refractory clays and red clays. 

Refractory plastic clays are rich in montmorillonite (formula (Si4.xAlx)(Alx. Rx)Oio(OH)2M2v(H20) with R = Mg, Fe + and M = K, Na), kaolinite or halloysite (Si2Al205(0H)4(H20)2). 

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The main raw material required for the production of viscose is ceUulose (qv), a natural polymer of D-glucose (Fig. 1). The repeating monomer unit is a pair of anhydroglucose units (AGU). CeUulose and starch (qv) are identical but for the way in which the ring oxygen atoms alternate from side to side of the polymer chain (beta linkages) in ceUulose, but remain on the same side (alpha linkages) in starch. 

Insulation. Impure sdiceous limestone and blast-furnace slag are the main raw materials for making rock-wool insulation bats and peUets (see Insulation, thermal). 

Until the mid-1950s the main raw material source for the European plastics industry was coal. On destructive distillation coal yields four products coal tar, coke, coal gas and ammonia. Coal tar was an important source of aromatic chemicals such as benzene, toluene, phenol, naphthalene and related products. From these materials other chemicals such as adipic acid, hexamethylenedia-mine, caprolactam and phthalic anhydride could be produced, leading to such important plastics as the phenolic resins, polystyrene and the nylons. 

Two of the main raw materials used for bioconversion to L-phenylalanine are frous-cinnamic acid and acetamido cinnamic add (reactions 1 and 2 in Figure 8.6.)... 

Fuels are of three types solid, liquid, and gaseous. Each category has been further classified into natural, manufactured, or by-product. Natural fuels are called primary fuels, while artificially produced fuels for a purpose or market, together with the products which are unavoidable by-product of some regular manufacturing process, are called secondary fuels. The main raw materials for secondary fuel are generally primary fuels. A list of the important fuels is shown in Table 1.22. 

The main raw material is styrene which is prepared as follows ... 

In 1989, the NDF Company opened a facility in Georgetown, South Carolina to produce low density polyethylene. Manufacturing of the polyethylene is done in two 50-ton reactors that are encased individually within their own 8-story-high process unit. The main raw materials for the manufacturing operations include ethylene, hexane, and hutene. The polymerization is completed in the presence of a catalyst. The hase chemicals for the catalyst are aluminum alkyl and isopentane. The reactor and catalyst preparation areas are on a distributed control system (DCS). A simplihed process flow diagram is attached. 

The main raw materials for the ARCO adipic acid process are butadiene, carbon monoxide and hydrogen. Process economics will be attractive in the next decade provided scenarios regarding the price of butadiene versus benzene come to fruitation. Table I. shows raw material cost for the ARCO adipic acid process versus conventional oxidation technology. For the time frame of this evaluation, the... 

Ninety five percent of the phosphorus on Earth belongs to the minerals of the apatite group. Apatites are inorganic constituents of bones and teeth of vertebrate and man, as well as a basis of many pathologic sohd formations. Minerals of the apatite group are the main raw materials in the production of phosphorus fertilizers, fodder and technical phosphates, elementary phosphorus, and phosphor-organic compounds. The mineral is sometimes substantially enriched in rare-earth elements (REE) making their extraction possible (Altshuller 1980). 

Silica Refractories. This type consists mainly of silica in three crystalline forms cristobalite [1446446-1]> tridymite [1546-32-3]> and quartz [14808-60-7]. Quartzite sands and silica gravels are the main raw materials, although lime and iron oxides are added to increase the mineralization of the tridymite and cristobalite. Uses include roof linings, refractories for coke ovens, coreless induction foundry furnaces, and fused-silica technical ceramic products. Consumption of silica refractories has declined dramatically since the 1960s as a result of the changes in the steel industry. 

Clay is the main raw material for the so-called classic ceramics. Its complex composition was elaborately discussed in chapter 8. For technical ceramics pure raw materials are needed (e.g. silicon nitride) which are often synthesized or the necessary raw materials are found in nature and subsequently purified very well, possibly after a chemical reaction has taken place. 

The United States imports about 70% of the world s opium. About 95% of that opium is consumed in the form of schedule III preparations, of which codeine is the most common. Until the mid-1970s, opium had been the main raw material used for the production of morphine and codeine. Since 1978, however, concentrate of poppy straw has been used with increasing frequency for that purpose. Poppy straw is a term used for the remainder of the poppy plant—but primarily refers to the seed capsule itself—once the seeds and opium-producing fluid have been removed. The majority of morphine and codeine production now comes from concentrate of poppy straw. 

The main raw materials used in epoxy adhesive formulations (resins and curing agents) can be synthesized in a variety of ways to create many different products. Epoxies react readily via several polymerization mechanisms. The extent of crosslinking is an important determinant of the final properties of the adhesive. Crosslinking can be controlled by the choice of resin and curing agent and by the curing conditions. 

Important sidelines are a list of the main raw materials and intermediates used in the synthesis of pesticides, as well as a list of all pesticides which are made using a given raw material or intermediate. 

Ammonia is basically the main raw material needed to manufacture AN. Some of the AN manufacturers make their own ammonia and some purchase it on the open market. It is obvious that the cost of manufacturing AN will depend on the price of ammonia and, even more basically, natural gas from which it is made. The volatility of ammonia prices is shown by the fact that in 1992 it cost 95 per ton and in 1995 the cost was 207 per ton.38... 

Although ASA has been marketed for more than 30 years, it is still a product with a considerable potential for new applications owing to the well-balanced cost-property relationship. The strength of ASA lies in the unique combination of its good weatherability, toughness, surface properties and resistance to chemicals. To be successful as an ASA supplier in the future the following prerequisites seem to be mandatory back integration for the main raw materials, innovative process and development, development of new applications coupled with a reliable and skilled technical customer support service. 

The main raw material is the fatty nitrile derived from the reaction of fatty acid with ammonia. Catalytic hydrogenation of the nitrile produces the amines. The amines are available as primary, secondary, and tertiary amine, depending on the number of the alkyl groups attached to the nitrogen atom. 

Kozo fibres are used as the main raw material. This is a thin, soft, pretty paper which has been manufactured in Gifu. Tengujo-paper is used for the core of hand-made fuses, when it is sprinkled with black powder. Popularly it has been used for packing valuable articles like silver or gold. 

Synthesis of DGEBA. As mentioned above, bisphenol A and epichlorohydrin are the main raw materials in the manufacture of... 

The main raw material are the so-called stoneware clays (Table 4) which are characterized by sintering even at 1200— 1300 °C but softening at substaintially higher temperatures. For this reason, they show a wide firing interval which allows safe firing even for large ware. 

The various types of technical ceramics have mostly been developed in laboratories. Their manufacture is usually based on new findings obtained in connection with the advances in various fields of science and technology although experience from the manufacture of traditional types of ceramics is also made use of. The respective materials are usually very sensitive to the maintenance of manufacturing conditions. This is why perfect control of the manufacturing processes, as well as that of the properties of the final products, is vital. With the exception of talc-based materials, the main raw materials are synthetic substances which provide better possibilites for maintaining constant properties and for their control. 

Forsterite is a refractory compound 2 MgO. Si02 (melting point 1890 0). It is also the main component of forsterite refractories which are dealt with in Section 7. Here we are concerned with forsterite fine ceramics for electrotechnical uses. The main raw material is again talc supplemented with a small amount of plastic clay, and MgC03 to redress the MgO-Si02 balance. The technological procedure is similar to that employed with the previous types. 

Traditional manufacture of ceramics is based on the use of fine natural raw materials which are capable of producing easily worked plastic mass (paste) with water. The formed bodies maintain their shape. The products are strengthened and the shape fixed by firing at temperatures which were attainable even in the primitive kilns. Kaolin and clays are the main raw materials which exhibit these required properties. 

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