Chemical and Metallurgical Industry

In the metallurgical industry, hydrogen is used as a reducing agent for manufacturing metal powders, such as tungsten and molybdenum. More hydrogen is used. 

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Zinc dust is used in the sherardizing process where work pieces are tumbled with zinc dust in rotating steel dmms which are heated electrically or by gas to 370—420°C (149). The steel parts are uniformly coated with zinc. In the chemical and metallurgical industries, zinc dust is used as a reducing agent, in the manufacture of hydrosulfite compounds for the textile and paper industries, and to enhance the physical properties of plastics and lubricants (2). 

The chemical and metallurgical industries of the world are so varied and extensive that it is impossible to cover all of the processes, emissions, and controls in a single chapter. 

Deller, A. W., Patent Law for Chemical and Metallurgical Industries, Chemical Catalog Co., New York, 1931. 

Answers to the first question showed that a list of chemical manufacturers or an official directory of chemical manufacturers had been published separately for only three states. Several replies, however, referred to Chemical Engineering 57) for October 1948 in which there was published a directory of prime producers of chemicals in the western states. Reference was also given to Principal Chemical and Metallurgical Industries of the Pacific Northwest—Information Circular No. 3 published by Raw Materials Survey, Portland, Ore. 60),... 

Forty-five states have published a directory of manufacturers. In each case, chemical manufacturers are included, and in most of these, they are grouped together under a separate heading. Although Washington and Oregon have not issued directories, the chemical manufacturers may be found in Principal Chemical and Metallurgical Industries of the Pacific Northwest compiled by the Industrial Division, Seattle Chamber of Commerce in January 1950 53) and also in 60) y mentioned previously. 

The estuarine sediment was collected in an amount of ca. 650 kg near the Zandvliet-locks in the Belgian part of the Scheldt Estuary using a Van Veen grab. This material was polluted with the effluents of chemical and metallurgical industries. The sediment was oven dried at 105°C in layers of approximately 5 cm, crushed and shipped to the Joint Research Centre of Ispra (Italy) for further processing. 

The non-transition metal complex hydrides have long been used as reducing agents in the pharmaceutical, chemical and metallurgical industries. They can be described by the general formula M(M H4) where M is a metal (typically Group 1 or 2) of the oxidation number n and M is a metal of Group 13 of oxidation... 

However, since reaction rates generally decrease with decreasing temperature, it is important to remember that a lower temperature always means that a reaction takes longer to reach equilibrium. This may not be a severe hindrance in the laboratory, but it is frequently a very important economic consideration in the chemical and metallurgical industries. 

Sulfuric acid is used in huge tonnages by the chemical and metallurgical industries, yielding even larger quantities of spent acid, which has to be distilled to recover the H2SO4. An initial guide is provided in Table 7.3, which lists the pertinent vapor-liquid compositions. 

Process control can involve the control or regulation of flows, pressures, liquid levels, chemical compositions, speed of rotation and other quantities, including temperature. However, I have chosen to concentrate on temperature for two reasons (i) temperature is an important factor in many chemical and metallurgical operations and its effects had been widely studied in laboratories and (ii) temperature measurement was well understood by the middle of the nineteenth century, since there were internationally recognised standard scales and calibration methods. Further there were laboratory instruments suitable for a wide range of temperature measurements. I also include within the domain of the chemical and metallurgical industries associated ancillary processes, such as the generation of steam. 

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