Special Precautions

Special PTFE bellows and gaskets should be used for connecting pipes Veiy firm, anti-vibration supports are necessary to prevent damage to glass-Uned vessels and connecting pipes. Rubber pads can be used at support lugs. 

Borosilicate glass items have better thermal/shock resistance and they should be treated with care 

Glass-lined equipment should be located away from vibrating machinery (such as compressors, crashers, pulverisers, etc.), sources of heat (high-temperature furnaces), exposure to high wind and rain, etc. 

Should be possible to easily erect, repair and dismantle the GL equipment and connected pipes, fittings, etc. Sufficient clearance should be provided on all sides of GL equipment for movement of men, materials and maintenance Raw materials with fluorides, HF, abrasive particles can damage lining Strainers should be provided in inlet lines to the vessel No raw material (solid or liquid) should be added rapidly it should be slowly introduced without hitting the GL shaft or agitator 

Most of the precautions to be taken for GL equipment are applicable to glass equipment also— with the added danger that the contents of the vessel can spill suddenly. Therefore, enclosures should be provided to arrest spillages (e.g. dyke walls, collection basin with AR tile lining) to prevent harm to personnel 

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The inflammable solvents most frequently used for reaction media, extraction or recrystallisation are diethyl ether, petroleum ether (b.p. 40-60° and higher ranges), carbon disulphide, acetone, methyl and ethyl alcohols, di-Mo-propyl ether, benzene, and toluene. Special precautions must be taken in handling these (and other equivalent) solvents if the danger of Are is to be more or less completely eliminated. It is advisable to have, if possible, a special bench in the laboratory devoted entirely to the recovery or distillation of these solvents no flames are permitted on this bench. 

Other sources of hazard arise from the handling of such chemicals as concentrated acids, alkalis, metallic sodium and bromine, and in working with such extremely poisonous substances as sodium and potassium cyanides. The special precautions to be observed will be indicated, where necessary, in the experiments in which the substances are employed, and will also be supplied by the demonstrator. The exercise of obvious precautions and cautious handling will in most cases reduce the danger to almost negligible proportions. Thus, if concentrated sulphuric acid should be accidentally spilled, it should be immediately washed with a liberal quantity of water or of a solution of a mild alkali. 

Xandiene dyes have not exhibited health or safety properties warranting special precautions however, standard chemical labeling instmctions are required. Toxicological properties of important dyes are Hsted in Table 2 (12). 

Despite the benefits of lead and lead ahoys, the use of these materials is declining rapidly, owing primarily to environmental health and safety factors. Eor many years, lead ahoys were the materials of choice for many corrosive environments, but are now being replaced by stainless steel, plastics, and exotic metals. The toxic nature of lead requires special precautions and handling not necessary with other materials. These requirements have reduced the usage of lead ahoys. 

Health and Safety Factors (Toxicology). No special precautions are necessary in the handling of malonic acid beyond normal safe handling measures. Due to its acidity malonic acid is classified as a mild irritant (skin irritation, rabbits). The LD q value (oral, rats) for malonic acid is 2750 mg/kg. Transport classification RID/ADR, IMDG-Code, lATA/lCAO not restricted. 

Operation and Control. Control of a chromium phosphate conversion coating bath requires monitoring chromium and aluminum concentrations, active fluoride level, and temperature. Coating weight is very sensitive to active, ie, uncomplexed, fluoride. An innovative electrochemical method using a siHcon electrode (25) is employed for measuring active fluoride. A special precaution in chromium phosphate bath operation is the... 

In most cases, the activator impurity must be incorporated during crystal growth. An appropriate amount of impurity element is dissolved in the molten Ge and, as crystal growth proceeds, enters the crystal at a concentration that depends on the magnitude of the distribution coefficient. For volatile impurities, eg, Zn, Cd, and Hg, special precautions must be taken to maintain a constant impurity concentration in the melt. Growth occurs either in a sealed tube to prevent escape of the impurity vapor or in a flow system in which loss caused by vaporization from the melt is replenished from an upstream reservoir. 

Chemical fertiliser is the predominant market for langbeinite. Comparatively small but increasing amounts of langbeinite are used by the animal feed ingredient industry (see Feeds and feed additives). Producers who supply this market must take special precautions to be sure that any langbeinite intended as an animal feed ingredient meets all USDA specifications for toxic heavy metals and other impurities. 

Special Precautions. Use of sodium nitrite or other nitrosating agents in formulations containing nikanolamines could lead to formation of suspected cancer-causing nitrosamines. 

Redistilled tetraethoxysilane containing less than 1 ppm chloride added to neutral 18 x 10 H water purged with nitrogen ia fluorocarbon bottles does not hydroly2e to a gel for over 6 months (10). Without special precautions, tetraethoxysilane hydroly2es to a gel ia - 10 d tetramethoxysilane... 

Components of sodium sulfates are easy to analyze using standard procedures. Except for normal analytical care in handling samples, no special precautions or procedures are required. 

Additionally, organotin mercaptides can act as antioxidants, as they can sequester free-radical degradation mechanisms (48). The one drawback of mercaptide-based tin stabilizers is the discoloration of the sulfur after exposure to uv-radiation. Special precautions or formulations need to be developed for outdoor apphcations. 

SmaH quantities of carbon tetrachloride can be shipped in 1, 5, and 55 gaHon (208 L) metal containers. Larger quantities are shipped by tank tmck, tank car, barge, and ship. Seamless stainless steel. Teflon, or seamless bronze hose is recommended with asbestos. Teflon, Viton, or neoprene gaskets. Special precautions should be taken to prevent contact with aluminum, magnesium metal, and their aHoys (48). 

Siace dimer acids, monomer acids, and trimer acids are unsaturated, they are susceptible to oxidative and thermal attack, and under certain conditions they are slightly corrosive to metals. Special precautions are necessary, therefore, to prevent product color development and equipment deterioration. Type 304 stainless steel is recommended for storage tanks for dimer acids. Eor heating coils and for agitators 316 stainless steel is preferred (heating coils with about 4s m (50 ft ) of heat transfer surface ia the form of a 5.1 cm schedule-10 U-bend scroU are recommended for a 37. 9-m (10,000-gal) tank. Dimer acid storage tanks should have an iaert gas blanket. 

Wool—Acrylic Fibers. This blend is being used for iadustrial and hand knitting yams. The acryHc fiber is aesthetically similar to wool, iacreases the strength of the yam, and adds bulk to the goods. Special precautions are necessary siace the two fibers are colored with dyes of opposite ionic type. Coprecipitation is prevented with the use of an antiprecipitant. Usually, level dyeing acid dyes are used for the wool portion in combination with the cationic dyes for acryHc fiber. 

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