Production, Use and Shipment

The world production of arsenic trioxide was about 50,000 tons in 1977. The US comsumes about half the total world production, and produces about 50% of what it consumes [11]. According to the National Academy of Sciences, exporters of arsenic include Mexico, Sweden, France, the Republic of South Africa, Peru, and the Phillipines [10]. The amounts of arsenic in the various copper, lead, and zinc concentrates range from parts per million (ppm) up to 15.5%. 

Agricultural uses account for most of the world consumption of arsenic. Arsenic trioxide is the raw material for arsenical pesticides, including lead arsenate, calcium arsenate, sodium arsenite, and organic arsenicals. Compounds like Paris green (copper acetoarsenite) were formerly popular insecticides in orchards, but are only of minor importance today. Lead arsenate and calcium arsenate have been used extensively for insect control on fruits, tobacco, cotton, and some vegetables, but current use is slight [10]. 

Organic arsenicals such as arsenilic acid, 3-nitro-4-hydroxyphenylarsonic acid, 4-nitrophenylarsonic acid, and p-ureidobenzenearsonic acid have been used as a feed additive since the 1950 s [4]. The U.S. Food and Administration approves of all four of these compounds for use in poultry and swine feeds but only at levels low enough to preclude residues in edible animal tissues which would be hazardous to human health [10]. In France and other countries almost all uses of these compounds are forbidden. 

Arsenic has an atomic weight of 74.9216, atomic number 33, and valences of 5, 3, 0,-3. Elemental arsenic occurs in two solid variations yellow, and gray or metal- 

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Production, Processing, and Shipment. Medium-density fiberboards (MDF) are panels made of fibrous raw material and used ia most of the same appHcations as particleboard. MDF products generally have more smooth surfaces and edges than particleboards and are thus preferred for some uses, even though the manufacture of MDF is more cosdy and the product is significantly more expensive. 

Production, Storage, and Shipment. As noted above, AUco Chemical, Amoco Chemical, Mitsubishi Gas Chemical, and Hbls all produce either the acid or the anhydride using different production techniques. The relatively small production volumes of pyromellitic acid and dianhydride results in both storage and shipment in polyethylene-lined fiber dmms of 22—136-kg capacity. 

Ammonia production requires storage facilities to smooth over fluctuations in production, usage and shipments. Ammonia is stored in bulk in large capacity containers installed above or below ground. It is distributed to point of use almost exclusively as a liquid. Gaseous ammonia sometimes is used within plants74. 

Production and Shipment. Estimated adiponitrile production capacities in the U.S. in 1992 were about 625 thousand metric tons and worldwide capacity was in excess of lO metric tons. The DOT/IMO classification for adiponitrile is class 6.1 hazard, UN No. 2205. It requires a POISON label on all containers and is in packing group III. Approved materials of constmction for shipping, storage, and associated transportation equipment are carbon steel and type 316 stainless steel. Either centrifugal or positive displacement pumps may be used. Carbon dioxide or chemical-foam fire extinguishers should be used. There are no specifications for commercial adiponitrile. The typical composition is 99.5 wt % adiponitrile. Impurities that may be present depend on the method of manufacture, and thus, vary depending on the source. 

Cost Fa.ctors, The dehvered costs of the phosphate rock and sulfuric acid raw materials often account for more than 90% of the cost of producing NSP, thus the production cost varies considerably with plant location. Because the rock is richer in P2O5 than is the low analysis NSP product, NSP need not be produced near the phosphate mine. However, deUvery of sulfuric acid and shipment of product to market are important cost factors. Most United States NSP plants have been located east of the Mississippi river, with concentration in the southeastern and extreme southern parts of the country where the largest use of the product has occurred. Production and use of the product also has been high in California. 

Economics. In contrast to NSP, the high nutrient content of TSP makes shipment of the finished product preferable to shipping of the raw materials. Plants, therefore, are located at or near the rock source. The phosphoric acid used, and the sulfuric acid required for its manufacture, usually are produced at the site of the TSP plant. As in the case of NSP, the cost of raw materials accounts for more than 90% of the total cost. Most of this is the cost of acid. 

The reduction of water limits mold formation, but only slightly affects the aroma or pungency. The dried product maintains its character and pound for pound is stronger in aroma and flavor than the fresh spice, since a nonessential component has been substantially removed. In areas where a spice is grown, the same product that is dried for storage and shipment is often used fresh for flavoring. 

Ionomers are generally shipped in pellet form in the standard containers developed for large-volume polyolefins, eg, 500-kg boxes. Water-resistant liners are used to keep the products dry during shipment and storage. 

The decomposition kinetics of an organic peroxide, as judged by 10-h HLT, largely determines the suitabiUty of a particular peroxide initiator in an end use appHcation (22). Other important factors ate melting point, solubiUty, cost, safety, efficiency, necessity for refrigerated storage and shipment, compatibihty with production systems, effects on the finished product, and potential for activation. 

After dewatering the cmmb it is fed to the drying process which is usually carried out in a continuous tunnel dryer. The cmmb is spread on a perforated stainless steel bed through which hot air is passed to evaporate the remaining water. Typically, in the first portion of the dryer, air at 110—140°C is used, with lower temperatures being used as the product approaches dryness. A typical target for final moisture content is 0.5% or less. At the exit of the dryer the product is cooled and conveyed to a baler which shapes it into bales for packaging and shipment. 

A company usually sets product standards in such a way as to minimize the purification expenses. These standards are often empirical tests to ensure that the buyer will get the same product in each shipment. Examples would be the melt index of a polymer, the boiling-point range of the product, and the maximum amount of certain impurities. Another manufacturer using a different process would want to set different standards. His method of production will be different, and so the amount and kind of impurities will be different. Sometimes this means expensive purification steps must be installed to meet the specifications set by the initial manufacturer. If this competitor could have been the initial standard-setter then these steps would not be necessaiy. 

In 1988, EPA prohibited the sale, distribution, and shipment of existing stocks of all canceled chlordane and heptachlor products. Subsequently, virtually all uses of heptachlor products were voluntarily canceled by the registrant, Velsicol Chemical Corporation (EPA 1990b). The only commercial use of heptachlor products still permitted is fire ant control in power transformers. Use of existing stocks of heptachlor-containing termiticide products in the possession of homeowners is also permitted (EPA 1990b). 

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