Materials carbonaceous

Note 2. The separation may be difficult owing to the presence of carbonaceous material. 

Perchlorates Carbonaceous materials, flnely divided metals particularly magnesium and aluminum, sulfur, benzene, oleflns, ethanol, sulfur, sulfuric acid... 

Perchloric acid Acetic acid, acetic anhydride, alcohols, antimony compounds, azo pigments, bismuth and its alloys, methanol, carbonaceous materials, carbon tetrachloride, cellulose, dehydrating agents, diethyl ether, glycols and glycolethers, HCl, HI, hypophosphites, ketones, nitric acid, pyridine, steel, sulfoxides, sulfuric acid... 

Preparation and Manufacture. Magnesium chloride can be produced in large quantities from (/) camalhte or the end brines of the potash industry (see Potassium compounds) (2) magnesium hydroxide precipitated from seawater (7) by chlorination of magnesium oxide from various sources in the presence of carbon or carbonaceous materials and (4) as a by-product in the manufacture of titanium (see Titaniumand titanium alloys). 

Other by-products include acetone, carbonaceous material, and polymers of propylene. Minor contaminants arise from impurities in the feed. Ethylene and butylenes can form traces of ethyl alcohol and 2-butanol. Small amounts of / -propyl alcohol carried through into the refined isopropyl alcohol can originate from cyclopropane [75-19-4] in the propylene feed. Acetone, an oxidation product, also forms from thermal decomposition of the intermediate sulfate esters, eg. 

Conrad Industries, Inc. (CentraUa, Washington) and Clean Air Products Company (Pordand, Oregon) have jointiy built a tire pyrolysis demonstration machine which allows recovery of combustible gases, oils, and other by-products. The equipment can also handle other carbonaceous material. It is designed to process 0.9 t/h of tires the entire system is estimated to cost about 2.3 x 10 . The feedstock consists of 5-cm tires chips which produce pyrolytic filler, a vapor gas yielding 11.5 kj/m (1000 Btu/ft ), and medium and light oils yielding about 42 MJ/kg (18,000 Btu/lb) (32). 

In ancient India, a steel called wootz was made by placing very pure kon ore and wood or other carbonaceous material in a tightly sealed pot or cmcible heated to high temperature for a considerable time. Some of the carbon in the cmcible reduced the kon ore to metallic kon, which absorbed any excess carbon. The resulting kon—carbon alloy was an excellent grade of steel. In a similar way, pieces of low carbon wrought kon were placed in a pot along with a form of carbon and melted to make a fine steel. A variation of this method, in which bars that had been carburized by the cementation process were melted in a sealed pot to make steel of the best quaUty, became known as the cmcible process. 

At red heat, a low carbon ferrous metal, in contact with carbonaceous material such as charcoal, absorbed carbon that, up to the saturation point of about 1.70%, varied in amount according to the time the metal was in contact with the carbon and the temperature at which the process was conducted. A type of muffle furnace or pot furnace was used and the kon and charcoal were packed in alternate layers. 

A number of high temperature processes for the production of titanium carbide from ores have been reported (28,29). The aim is to manufacture a titanium carbide that can subsequently be chlorinated to yield titanium tetrachloride. In one process, a titanium-bearing ore is mixed with an alkah-metal chloride and carbonaceous material and heated to 2000°C to yield, ultimately, a highly pure TiC (28). Production of titanium carbide from ores, eg, ilmenite [12168-52-4], EeTiO, and perovskite [12194-71 -7], CaTiO, has been described (30). A mixture of perovskite and carbon was heated in an arc furnace at ca 2100°C, ground, and then leached with water to decompose the calcium carbide to acetjdene. The TiC was then separated from the aqueous slurry by elutriation. Approximately 72% of the titanium was recovered as the purified product. In the case of ilmenite, it was necessary to reduce the ilmenite carbothermaHy in the presence of lime at ca 1260°C. Molten iron was separated and the remaining CaTiO was then processed as perovskite. 

Property Modifiers. Property modifiers can, in general, be divided into two classes nonabrasive and abrasive, and the nonabrasive modifiers can be further classified as high friction or low friction. The most frequently used nonabrasive modifier is a cured resinous friction dust derived from cashew nutshell Hquid (see Nuts). Ground mbber is used in particle sizes similar to or slightly coarser than those of the cashew friction dusts for noise, wear, and abrasion control. Carbon black (qv), petroleum coke flour, natural and synthetic graphite, or other carbonaceous materials (see Carbon) are used to control the friction and improve wear, when abrasives are used, or to reduce noise. The above mentioned modifiers are primarily used in organic and semimetallic materials, except for graphite which is used in all friction materials. 

The prime requirement of any carbonaceous material used in the blast furnace hearth wall or bottom is to contain Hquid iron and slag safely within the cmcible, throughout extended periods of continuous operation, often up to 15 years. 

The process for the thermal activation of other carbonaceous materials is modified according to the precursor. For example, the production of activated carbon from coconut shell does not require the stages involving briquetting, oxidation, and devolatilization. To obtain a high activity product, however, it is important that the coconut shell is charred slowly prior to activation of the char. In some processes, the precursor or product is acid-washed to obtain a final product with a low ash content (23,25). 

At pressures of 13 GPa many carbonaceous materials decompose when heated and the carbon eventually turns into diamond. The molecular stmcture of the starting material strongly affects this process. Thus condensed aromatic molecules, such as naphthalene or anthracene, first form graphite even though diamond is the stable form. On the other hand, aUphatic substances such as camphor, paraffin wax, or polyethylene lose hydrogen and condense to diamond via soft, white, soHd intermediates with a rudimentary diamond stmcture (29). 

D. M. Riggs, The Characterisation andKinetic Mechanism of Mesophase Formation in High Molecular Weight Carbonaceous Materials, Ph.D. dissertation, Rensselaer Polytechnic Institute, Troy, N.Y., 1979. 

Catalysts in this service can deactivate by several different mechanisms, but deactivation is ordinarily and primarily the result of deposition of carbonaceous materials onto the catalyst surface during hydrocarbon charge-stock processing at elevated temperature. This deposit of highly dehydrogenated polymers or polynuclear-condensed ring aromatics is called coke. The deposition of coke on the catalyst results in substantial deterioration in catalyst performance. The catalyst activity, or its abiUty to convert reactants, is adversely affected by this coke deposition, and the catalyst is referred to as spent. The coke deposits on spent reforming catalyst may exceed 20 wt %. 

The buildup of carbonaceous materials in the sulfuric acid presents one of the most serious problems of acid concentration (76—80). Acid concentration also presents a corrosion problem. The vessels are mild steel lined with lead or brick the steam heating elements are composed of siUcon, iron, or tantalum, and pipelines are generally constmcted of lead (81). 

Phosphate rock is calcinedto remove carbonaceous material before being oigested with sulfuric acid. Several different fluidization... 

This is not the case in most fires where some oi the intermediate produces, formed when large, complex molecules are broken up, persist. Examples are hydrogen cyanide from wool and silk, acrolein from vegetable oils, acetic acid from timber or paper, and carbon or carbon monoxide from the incomplete combustion of carbonaceous materials. As the fire develops and becomes hotter, many of these intermediates, which are often toxic, are destroyed—for example, hydrogen cyanide is decomposed at about 538°C (1000°F). 

Small airborne particles of partially burnt carbonaceous materials from smoke, which is often made more opaque by steam from combustion or from water added to the fire, may be formed when there is only partial combustion of fuel. 

Coke Coke is the solid, cellular, infusible material remaining after the carbonization of coal, pitch, petroleum residues, and certain other carbonaceous materials. The varieties of coke generally are identified by prefixing a word to indicate the source, if other than coal, (e.g., petroleum coke) or the process by which a coke is manufactured (e.g., oven coke). 

Other carbonaceous materials such as municipal waste plastics, cel-hilosics, and used motor oils may also serve as cofeedstocKs with coal in this technology. 

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