Machine-Chemical Reduction

High density tungsten alloy machine chips are recovered by oxidation at about 850°C, foUowed by reduction in hydrogen at 700—900°C. Typically, the resultant powders are about 3-p.m grain size and resinter readily. There can be some pickup of refractory materials used in furnace constmction, which must be controUed. This process is important commercially. Eor materials that may be contaminated with other metals or impurities, the preferred recovery process is the wet chemical conversion process used for recovery of tungsten from ores and process wastes. Materials can always be considered for use as additions in alloy steel melting. 

Planarization- Chemical mechaniced planjurization machines are used to level the topology of the films deposited on the wafer. Chemical-mechanical smoothing is the process used to improve process uniformity, repeatability, removal rate, planarity and defeet reduction. Thus, planarization is requisite to producing defect-free CMOS circuits. 

MgS04 as stabilizers, and are non-selective in degrading also cellulose and hemicelluloses, while the reductant 820/ is more selective but less effective, and generates various sulfur-containing chemicals including thiosulfate that is corrosive to paper machines (3). 

The chemical systems for RIM all have one characteristic in common they require a RIM machine to convert liquid raw materials into quality plastic products. Assuming a properly formulated chemical system, the quality of the end product results from the ability to measure, control (Chapter 3), and adjust temperature, ratio, pressure, and other essential process parameters of the RIM dispensing machine. Such exacting control leads to a reduction in start-up time, minimal rejects and touch-up work, reproducible product quality, and the ability to pinpoint changes in product properties. 

Before undertaking our research on catalytic reductions we devised a practical machine whereby we might operate on a quantitative basis with large quantities of reagents. A description of this machine and a complete record of our preliminary work on uracil reduction will be published in a future number of the Journal of the American Chemical Society. 

Qiersieden Schwedes, "Experiences with machines used for wet reduction in the Chemical Industry" Chemie Ingenieur Technik I982... 

A reduction in the volume of water needed at the paper machine is almost impossible because paper formation will be disturbed if the consistency of the pulp suspension becomes too high. Currently, the stock suspension (i.e., pulp and additives) in the head box of a paper machine contains 97%-99.9% water. The constraint of maintaining pulp suspension consistency means a reduction in water intake has to be realized by reusing the process water. Due to the different purposes and applications in which water is used, the water quality demands vary considerably. Membrane processes can be chosen to produce a specific water quality and are attractive alternatives to facilitate the reuse of water, either alone or combined with biological processes or other chemical and physical processes. In addition, membrane processes are an efficient way to recover raw materials, e.g., coating pigments, from effluents. 

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