High abrasion furnace grade

The polychloroprene rubber preferred is the Neoprene W type. Neoprene G would perhaps give slightly superior properties, but W-type gives the best compromise between properties and processability, (ref. 3). A special low-viscosity grade, similar to W-Ml is used. The compound contains approximately 40 phr high abrasion furnace (HAF) black to reinforce it. 

Alumina is traditionally formed via thermal dehydration of aluminum hydroxides [94,95]. The final size and crystallinity of the alumina abrasives largely depend on the temperature and time of the thermal treatment process. It has been reported that the total reaction conversion occurs at a temperature of 1500 K. Technical grades of calcined alumina are commonly used for smelting, ceramics, and abrasive particles. Other common forms of alumina produced are fused and white tabular alumina. Fused alumina is produced by melting calcined alumina at a high-temperature furnace for extended time periods. White tabular alumina is composed of large well-developed crystals of... 

The "conventional" methods for the preparation of SiC and Si3N4, the high temperature reaction of fine grade sand and coke (with additions of sawdust and NaCl) in an electric furnace (the Acheson process) for the former and usually the direct nitridation of elemental silicon or the reaction of silicon tetrachloride with ammonia (in the gas phase or in solution) for the latter, do not involve soluble or fusible intermediates. For many applications of these materials this is not necessarily a disadvantage (e.g., for the application of SiC as an abrasive), but for some of the more recent desired applications soluble or fusible (i.e., proces-sable) intermediates are required. 

Carbon black is the most important and powerful filler for rubbers. Each of the above characteristics of the carbon black has its effect on the properties of rubber in which carbon black is incorporated and careful selection of grade is necessary to ensure a correct balance of processing and vulcanising properties. The furnace black type, which has fine particle size, is used in lining, where high strength and resistance to abrasion are required. 

Abrasive and refractory grade silicon carbide is produced industrially by the car-bothermal reduction of silica, according to the reaction in Eq. (3), from high-purity quartz sand (99.5% Si02) and petroleum coke, in electrically heated resistance furnaces (Acheson furnace) [47]. The reaction is strongly endothermic the heat of formation is 618 kj mol SiC, corresponding to 4.28 kWh kg SiC. 

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