Particle size, sulfur

Sulfur-coated urea is produced ki North America by a number of suppHers including ICl Canada (Courtright, Ontario), Lesco, Inc. (Martins Ferry, Ohio), PurseU Industries (Sylacauga, Alabama), and The O.M. Scott Sons Co. (Marysville, Ohio). All produce a number of fertilizer grades and particle sizes. Sulfur-coated ureas and compound (N—P—K) fertilizers also are produced by Mitsui Toatsu (Japan). 

Ma.nufa.cture. Nitroguanidine may be made by several methods. In all the processes guanidine nitrate is the iatermediate which is then dehydrated with sulfuric acid. When used ia propellants, the average particle size of nitroguanidine has to be carefully controlled. 

Essentially all the ammonium sulfate fertilizer used in the United States is by-product material. By-product from the acid scmbbing of coke oven gas is one source. A larger source is as by-product ammonium sulfate solution from the production of caprolactam (qv) and acrylonitrile, (qv) which are synthetic fiber intermediates. A third but lesser source is from the ammoniation of spent sulfuric acid from other processes. In the recovery of by-product crystals from each of these sources, the crystallization usually is carried out in steam-heated sa turator—crystallizers. Characteristically, crystallizer product is of a particle size about 90% finer than 16 mesh (ca 1 mm dia), which is too small for satisfactory dry blending with granular fertilizer materials. Crystals of this size are suitable, however, as a feed material to mixed fertilizer granulation plants, and this is the main fertilizer outlet for by-product ammonium sulfate. 

Reactivity is affected by particle size. Smaller particles react faster. However, the dominant factor for reactivity is the soHdification rate. Material that is soHdified quicker reacts faster with alcohol (30). Commercial P4S q is a soHd solution containing P4S2Q, P4SC), P4Sy, free sulfur, etc (33). SoHdification rate... 

By-Product Calcium Sulfate. There are many iadustrial chemical processes that produce by-product calcium sulfate in one of its forms. Whereas the most common is the neutralization of spent sulfuric acid, many of those processes do not produce a commercially useful by-product because of contaminants, particle size, or volume produced. There are, however, six chemical processes that do produce sufficient volume to have potential commercial value. Each is named after its chemical process. 

The color obtained is a function of both the composition and the particle size of the precipitated crystals. A redder color results from both increased selenium to sulfur ratio and from larger crystals, caused by a more severe heat treatment. Hence, it is possible to make, from the same glass, a series of color filter types, by controlled reheating. 

Compo- sition number Resin type/parts per 100 parts of mbber (phr) Sulfur (phr) Y Method of preparation Cross- link density, r/2 (moles X 10 per ml of mbber) Rubber particle size (pm) Young s modulus (MPa) Stress at 100% strain (MPa) Tens. str. (MPa) UlL elong. (%) Tens. set (%)... 

Inhaled gaseous compounds are absorbed in all parts of the respiratory system whereas particle size determines how deep into the airways the parti cles will he transported in the airstrearn. Shortness of breath is a typical sign of a chemical exposure that has affected the lungs, and it may be evoked through iminunological mechanisms (e.g., formaldehyde, ethyleneoxide), or through toxic irritation (formaldehyde, isocyanates, sulfur dioxide, nitrogen dioxide, Frequently the mechanism depends on the concentration ol the com... 

It was shown in laboratory studies that methanation activity increases with increasing nickel content of the catalyst but decreases with increasing catalyst particle size. Increasing the steam-to-gas ratio of the feed gas results in increased carbon monoxide shift conversion but does not affect the rate of methanation. Trace impurities in the process gas such as H2S and HCl poison the catalyst. The poisoning mechanism differs because the sulfur remains on the catalyst while the chloride does not. Hydrocarbons at low concentrations do not affect methanation activity significantly, and they reform into methane at higher levels, hydrocarbons inhibit methanation and can result in carbon deposition. A pore diffusion kinetic system was adopted which correlates the laboratory data and defines the rate of reaction. 

The various sohd sulfur allotropes are all more or less yellow at 20 °C but the scale ranges from the deep orange-yellow of to the pale yellow of S. The color also depends on the particle size As finer the particles as lighter the color impression. Chemically produced Ss has in fact occasionally been obtained as a colorless material at room temperature which only slowly turns yellow as the initially tiny crystals grow [61]. The sample temperature is also of decisive influence (thermochromic effect) [10] (see above). 

The interaction of adsorbed thiol molecules with gold nanoparticles as a function of the mean particle size has also been studied [180]. Monochromated X-ray Photoelectron Spectroscopy (MXPS) measurements showed the attachment of the thiol sulfur headgroup onto the cluster surface leading to a positive BE shift in the Au 4f corelevel. No line width broadening could be observed indicating that the thiol-gold interaction affects the whole... 

Air temperature and vapor density are two factors which influence the rate of dissipation of radiant energy received by plants from the sun, and they determine in a large measure the temperature of the plant part and consequently sunburn and sulfur burn (18), other factors, such as particle size of the sulfur, being constant. 

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