Coming mill

Fig. 106. Remote, control of a machine dangerous to operate (coming mill) in a blackpowder factory [60].

The pressed cakes of explosive are broken up in a coming mill, the construction of which is shown in Fig. 166. After passing through breaking rollers (7) and (2) the material passes through a leather sleeve to sieves (5) (13 mm mesh) and (4) (6 mm... 

Fig. 166. Schematic view of a coming mill for ammonium nitrate explosive.

In any case it has to be taken into account, that the paper mills have to reduce their shut down periods to an absolute minimum because of the economical pressure coming from the globalisation of the industry. 

Funding for developing commercial waste disposal faciUties is to come from the waste generators. In the case of spent fuel disposal, a Nuclear Waste Fund is accumulating based on an assessment of one mill per kilowatt-hour of electricity. For low level wastes, surcharges on waste disposal and direct assessments of utiUties have been imposed. 

The defoamer formulations mentioned so far consist of fairly inexpensive raw materials, but several more cosdy defoaming materials have come into use in paper mills. Hydrophobicized siUca particles are useful in some emulsion formulations. SiUcone solutions and emulsions are very effective in eliminating foam in paper machine water systems. The siUca- or siUcone-based defoamers have higher activity, which somewhat compensates for the higher cost, but care must be taken to prevent ovemse. 

Closed-Mill Concept. The closed-mill concept, or water circuit closure, has been studied by the pulp and paper industry for many years. In some parts of the paper manufacturing process, up to 98% of the water is recycled within the process, eg, the wet end of the paper machine. However, in the pulp mill, especiaUy kraft mills, effluents are produced owing to the need to purge from the system various metals that come in with the wood, as weU as organic by-products from the pulping process, additives, and especially chloride ions that originate in the bleach plant. 

The avadabihty of prompt iadustrial scrap is directiy related to the level of iadustrial activity. Producers geaeraHy do aot accumulate prompt iadustrial scrap because of storage requiremeats and iaventory control costs. Thus, it is rapidly available to the scrap consumer or the ferrous scrap iadustry. Prompt iadustrial scrap comes from imported steel as well as domestic steel mill products. Obsolete scrap, also known as old or post-coasumer scrap, is widely used. Treads ia aew steelmaking capacity and the reduced proportions of premium scrap iadicate that use of obsolete scrap should be expected to iacrease. 

Water Clarification. Process water that aeeds to be clarified comes from several differeat sources ia the recycling mill rejects from screeas and mechanical cleaners rejects from washers, thickeners, and flotation cells water that drains from the pulp as it is converted iato paper oa the paper machine (white water) and water from felt washers. These waters contain different dissolved chemicals and suspended soflds and are usually processed separately. 

The majority of the turpentine comes from the southeastern United States, which consists of 60—70% a-pinene, 20—25% P-pinene, and 6—12% other components. Because there is variation in components from different species of the pine tree as well as variation from the many paper pulp mills, there is obviously variation in the analysis of sulfate turpentines. Some of the other components consist of -menthadienes, alcohols, ethers such as anethole [104-46-1] and methylchavicol [104-67-0] and the sesquiterpene hydrocarbon, P-caryophyUene [87-44-5]. 

The choice of selected raw materials is very wide, but they must provide calcium oxide (lime), iron oxide [1309-37-1/, siHca, and aluminum oxide (alumina). Examples of the calcereous (calcium oxide) sources are calcium carbonate minerals (aragonite [14791-73-2] calcite [13397-26-7] limestone [1317-65-3] or mad), seasheUs, or shale. Examples of argillaceous (siHca and alumina) sources are clays, fly ash, mad, shale, and sand. The iron oxide commonly comes from iron ore, clays, or mill scale. Some raw matedals supply more than one ingredient, and the mixture of raw matedals is a function of their chemical composition, as deterrnined by cost and availabiHty. 

In the United States about 3 percent of all electricity produced comes from renewable sources of this a little more than half comes from biomass. Most biomass energy generation comes from the lumber and paper industries from their conversion of mill residues to in-house energy. Municipal solid waste also is an important fuel for electricity production approximately 16 percent ot all municipal solid waste is disposed of by combustion. Converting industrial and municipal waste into bioenergy also decreases the necessity for landfdl space. 

The top and the bottom x-ray detector each contain a multiplier phototube coated with phosphor. This tube compares the intensity of the x-ray beam entering the detector with that of the light from the reference standard, a discharge lamp. The reference beam is part of a circuit that maintains the x-ray source at constant intensity. The deviation wedge comes to rest when the intensities of the transmitted x-ray beams stand in a predetermined ratio. At this point, the unbalance in the servo system has been compensated, and the position of the deviation wedge consequently indicates the thickness of the strip. In 1955, this application was made fully automatic that is, the unbalance (or error signal) just mentioned was used to readjust tandem cold reduction mills of the United States Steel Corporation. Automatic control proved significantly more effective than manual control. 

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