Chemical milling process

CHEMICAL MILLING PROCESS CAPABILITV MAP FOR CARBON STEELS... 

CHEMICAL MILLING PROCESS CAPABILITY CHART FOR ALUMINIUM ALLOYS... 

The fiber extraction (milling) process must be chosen so as to optimize recovery of the fibers in the ore, while minimizing reduction of fiber length. Since the asbestos fibers have a chemical composition similar to that of the host rock, the separation processes must rely on differences in the physical properties between the fibers and the host rock rather than on differences in their chemical properties (33). 

The processes occurring in a high-speed newsprint paper machine have been discussed above. There are several additional considerations of note in the overall process picture. Paper for the most part is a commodity item (i.e., production costs are more economical per unit when large tonnages of uniform specifications are produced). Most mills have a break-even point at an 85% capacity so it is vital to operate mills at design capacity. Economies of scale are also found for pulp and paper mills at levels of about 1000 tonnes of paper per day for full chemical mills and 200—400 tonnes of paper per day for semichemical or mechanical mills. Thus, the outputs of paper mills are... 

Since the prices of petroleum products have soared, valorization of natural resources has intensively attracted the attention of researchers in different fields. To fully utilize wood, which is a renewable raw material, one must make better use of its 25-30% lignin content which forms the principal dissolved material in the spent liquor of chemical pulping processes. The annual production of sulfite pulp in Canada is approximately 2.6 million tons (data based on 1979), thus, at least one million tons of lignosulfonate is produced, representing a potential resource of raw material for other uses. However, among 35 sulfite mills in Canada, only two or three of them possess a recovery system for spent liquor, that means a very small portion of lignosulfonate has been recovered. The recovered lignin has been... 

Alkali was the first chemical used in corn wet-milling,275 but was quickly abandoned in favor of sulfur dioxide. Researchers over the years have tried to refine the use of alkali for starch processing,1718 276 because of the ease with which alkali solubilizes endosperm protein. An alkali wet-milling process which yields —2% more starch and has —40% lower capital cost has been developed.277... 

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