Leading lines

Mild steel is a satisfactory constmction material for all equipment in Ziegler chemistry processes except for hydrolysis. If sulfuric acid hydrolysis is employed, materials capable of withstanding sulfuric acid at 100°C are requited lead-lined steel, some alloys, and some plastics. Flow diagrams for the Vista and Ethyl processes are shown in Eigures 3 and 4, respectively. 

Depending on the chemical nature of the slurry to be filtered, materials of constmction include wood, plastics, earthenware, steel, lead-lined steel, and brick-lined cast iron. 

Sodium fluoride is normally manufactured by the reaction of hydrofluoric acid and soda ash (sodium carbonate), or caustic soda (sodium hydroxide). Control of pH is essential and proper agitation necessary to obtain the desired crystal size. The crystals are centrifuged, dried, sized, and packaged. Reactors are usually constmcted of carbon brick and lead-lined steel, with process lines of stainless, plastic or plastic-lined steel diaphragm, plug cock, or butterfly valves are preferred. 

Minor quantities of arsenic trioxide have been obtained from the roasting of arsenopyrite, but the presence of copious amounts of SO2 iu the gas and vapor stream requires the use of lead-lined kitchens (9). 

Benzyl chloride is available in both anhydrous and stabilized forms. Both forms can be shipped in glass carboys, nickel and lined-steel dmms, and nickel tank tmcks and tank cars. Stabilized benzyl chloride can be shipped in unlined and lacquer-lined dmms, and tank tmcks or cars of constmction other than nickel. Glass-lined tanks are the first choice for bulk storage of anhydrous benzyl chloride lead-lined, nickel, or ceramic tanks can also be used. 

Plating T anks. An electroless plating line consists of a series of lead-lined (for plastics etching) or plastic-lined tanks equipped with filters and heaters, separated by rinse tanks (24). Most metal tanks, except for passivated stainless steel used for electroless nickel, cannot be used to hold electroless plating baths because the metal initiates electroless plating onto itself. Tank linings must be stripped of metal deposits using acid at periodic intervals. 

After being cleaned, ware that is to be pickled is immersed successively in one or more tanks of water at 80—95°C and then transferred to the acid pickling solution. The pickling solution of 6—8% sulfuric acid is contained in a stainless steel tank or, alternatively, a lead-lined wooden tank at 60—65°C. 

Piping—carbon steel, alloy, cast iron, lead-lined, aluminum, copper. Purchasing, expediting, and traffic... 

Lead and Lead-Lined Steel Pipe Lead and lead-hned steel lipe have been essentially eliminated as piping materials owing to lealth hazards in fabrication and installation and to environmental objections. Lead has been replaced by suitable plastic, reinforced plastic, plastic-lined steel, or high-alloy materials. 

Both steel and copper vessels may be lined with thin silver sheets in the same way as for homogeneous lead lining. As silver is extremely resistant to most organic acids at all concentrations and temperatures, it is used widely for handling foodstuffs and pharmaceutical products where nontoxicity and... 

World production of Bra in 1990 was about 438 000 tonnes pa, i.e. about one-hundredth of the scale of the chlorine industry. The main producing countries are (tonnes) USA 177000, Israel 135 000, Russia 60000, UK 28 000, France 18 000 and Japan 15 000. The production capacity of Israel has recently increased almost threefold because of expanded facilities on the Dead Sea. Historically, bromine was shipped in individual 3-kg (net) bottles to minimize damage due to breakage, but during the 1960s bulk transport in monel metal drums (100-kg capacity) or lead-lined tanks (24 or 48 tonnes) was developed and these are now used for transport by road, rail and ship. The price of Bra in tank-car lots was 975/kg in 1990. 

Blei-asche, /. lead dross lead ash the gray film of oxide on lead exposed to air. -aus-kleidung, /. lead lining. -azetat, n. lead acetate, -bad, n. lead bath, -bauzn, m. lead tree, arbor aaturni. 

Bleigang, m. (Mining) lead vein, bleigefiittert, a. lead-lined. 

Verbleiung,/. leading lead lining, verblenden, v.t. blind, dazzle dim, black out ... 

Chlorine gas was gradually passed into 660 parts of benzene contained in a lead-lined reaction vessel until 890 parts of the gas had been absorbed. The mixture was stirred continuously and the temperature maintained at 15°C to 20°C. 

Plastic coated metals, lead lined aluminum, lead lined copper. 

The nuclear reactor also must be shielded against the emission of radioactive material to the external environment. Suitable radiation controls include both thermal and biological shielding systems. Radiation from alpha particles (a rays) and beta particles ((3 rays) has little penetrating power, but gamma rays have deep penetration properties. Neutron radiation is, however, the primary area of risk. Typically, extremely thick concrete walls are used as a neutron absorber, but lead-lined concrete and special concretes are also used. 

Radiation exposure can be reduced by placing the radiation source or the potential target behind a shield that captures the radiation. During exposure to X rays for dental imaging, the patient wears a lead-lined pad, because X rays are absorbed more effectively by lead than by any other material. A lead shield a few millimeters thick is sufficient to stop X rays. 

Storage stability Stable in glass, lead-lined, or enamel-lined containers reaction with iron may be explosive. Vigorous corrosive action on all common metals except lead reaction with iron may be explosive. 

Creep is the gradual extension of a material under a steady tensile stress, over a prolonged period of time. It is usually only important at high temperatures for instance, with steam and gas turbine blades. For a few materials, notably lead, the rate of creep is significant at moderate temperatures. Lead will creep under its own weight at room temperature and lead linings must be supported at frequent intervals. 

Equations 2, 3, and 4 summarize the method proposed by the Germans for preparing parathion (compound E-605). Schrader 13) has reported that thiophosphoryl chloride was synthesized from phosphorus trichloride and sulfur by heating at 130° in a lead-lined autoclave. Woodstock and Adler 14) carried out a similar reaction at 150° to 160° C. 

Sulfuric acid had been readily available since 1746 when John Roebuck of Birmingham, England, began making it in lead-lined, wooden boxes several stories high. 

During the 1960s, Americans lived in a lead-drenched society. They fueled their cars with leaded, antiknock gasoline. They ate food and their babies drank milk from lead-soldered cans. They stored drinking water in lead-lined tanks and transported it through lead or lead-soldered pipes. They squeezed toothpaste from lead-lined tubes and poured wine from bottles sealed with lead-covered corks. They picked fruit sprayed with lead arsenate pesticide and served it on lead-glazed dishes in houses painted and puttied with lead-based compounds. 

Letter to Wilder D. Bancroft, Jan. 19, 1923. Lead-lined lungs. Kettering... 

For aluminum multiply by 1.4 for rubber-lined, multiply by 1.48 for lead-lined, multiply by... 

Musculoskeletal Effects. Individuals who have had high exposures to lead, either occupationally or by the consumption of alcohol from lead stills, have been reported to exhibit a bluish-tinged line in the gums (i.e., the "lead line"). In addition, case reports of high occupational exposure to lead have described the occurrence of muscle weakness, cramps, and joint pain. 

An explosive variety (or compound) of arsenic was produced as a surface layer on the exposed iron surfaces of a corroded lead-lined vessel which contained 35% sulfuric... 

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