Processing aids/additive

Figure 15. Plot of oil recoveries versus process aid addition level from the hot water flotation processing of an oil sand in a continuous pilot plant. Also shown is the correspondence with the zeta potentials, measured on-line, of emulsified bitumen droplets in the extraction solution. (Plotted from data in reference 50.)...

Processing aids - additives such as viscosity depressants, mold-release agents, emulsifiers, lubricants, and anti-blocking agents (3). 

Constituents in plastics (residues, processing aids, additives and master batching)... 

Constituents identified in terms of residues (from polymerisation process), processing aids, additives, masterbatch constituents. 

Figure 23. The variation of in situ suspension viscosity with depth in the primary flotation vessel of Figure 21, for two different process aid addition levels zero NaOH addition and 0.025 mass% relative to the oil sand (a). The high viscosities at shallow depths correspond to the froth layer. (Reproduced with permission from reference 66. Copyright 1989 Canadian Institute of Mining, Metallurgy, and Petroleum.)...

For rich grade oil sands, the addition of a base such as NaOH is usually not necessary and simply slurrying with hot water is all that is needed to release sufficient quantities of natural surfactants into the aqueous phase. For lower grades of oil sand, NaOH process aid addition is needed to optimize bitumen recovery. In this case, only a small fraction of the NaOH added in processing reacts to produce the natural surfactants while the major portion (ca. 90%) reacts with minerals (to produce mostly bicarbonate) [70, 102-104]. 

Figure 18. Correlation between process aid additions for maximum primary bitumen recovery and process aid additions required to attain maximum bitumen/aqueous surface charge (Zeta potential). The data are for continuous pilot plant operation (Hj and laboratory batch extractions (%). (From Schramm and Smith [111].)...

In addition to being used as processing aids, additional antioxidant is sometimes incorporated in the polymer after moulding. This applies to applications where relatively high temperatures are involved as in contact with hot foods, infrared ovens or in tropical areas where substantial exposure to ultraviolet radiation is likely to be encountered. 

Recommended reverse ester tin stabilizers include Thermolite 140, 172 butyltins and 174 methyltin Mark 1367 butyltin and 1939,1971,2903 methyltins Advastab TM-286SP and Interstab T-5201 and 5286. Substrate recipes may also include 0.15-0.25 phr of a lubricating processing aid. Addition of zeolite or hydrotalcite at a level of 0.5-1.0 phr will enable use of the low end of the above recommended usage and will provide for gradual rather than abrupt failure in case of factory misadventure. A suitable costabilizer for this purpose is Halstab 1214 coated zeolite. 

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