Caustic definition

Spent caustic solutions from petroleum refining. Petrochemical refineries use caustics to remove acidic compounds such as mercaptans from liquid petroleum streams to reduce produced odor and corrosivity as well as to meet product sulfur specifications. Spent liquid treating caustics from petroleum refineries are excluded from the definition of solid waste if they are used as a feedstock in the manufacture of napthenic and cresylic acid products. U.S. EPA believes that spent caustic, when used in this manner, is a valuable commercial feedstock in the production of these particular products, and is therefore eligible for exclusion. 

In addition to the sulfur compounds listed above, hydrogen sulfide has been found in many crude petroleums. Elemental sulfur has been definitely found in several crude petroleums by API Research Project 48 (23). Although Birch and Norris (5) isolated several disulfides from the spent caustic used in treating gasoline from Iranian petroleum, these compounds may have resulted from the oxidation of the thiols and their presence in the original petroleum is regarded as doubtful. Other types of sulfur compounds, such as thiophenes and aromatic thiols, have been identified in cracked petroleum products, but the presence of such compounds in naturally occurring petroleums has not yet been established. 

We are told by H. Davy that, in 1790, M. Tondi attempted to obtain the constituent elements of these earths by heating a mixture of the oxide with carbon. In some cases he obtained metallic reguli. H. Davy also pointed out that G. E. Stahl approached very nearly to the discovery of the pure alkalies, for he exposed a mixture of solid caustic potash and iron filings to a long-continued heat, and stated that in this way an intensely caustic alkali—valde causticum—is produced. The oxides were not definitely resolved into their elements until 1807, when H. Davy isolated potassium and sodium by the electrolysis of their hydroxides. 

In the coal treated by molten caustic in Run 2, the Cr and Ni levels are significantly higher than in Run 1, suggesting a more severe attack in the second test. If the attack were more severe, then levels of Fe, Al, Si, and ash would be anticipated to be somewhat lower than in Run 1. As can be seen from these data, this is indeed the case. However, because of the numerous variables involved, no definitive conclusions can be drawn. Overall trace element reductions did not seem to be significantly improved in Run 2. 

CAUTION Sodium hydroxide in any concentration is a bit caustic and definitely a skin irritant. Wear goggles and gloves. 

Chemical refining Sequence of process stages, which definitively includes alkali refining (also referred to as caustic refining or neutralization) to remove most of the FFA and, in most cases, also deodorization in the last stage. 

Note that the recovery column is still a liquid/liquid extractor however, the toluene s role is now the raffinate and the caustic water is the solvent. In addition, the distribution coefficient needs to be defined as or the inverse of the definition for the... 

SOda, modified. (neutral soda). A combination of soda ash and bicarbonate of soda in definite proportions for purposes where an alkali is needed, ranging in causticity between bicarbonate of soda and soda ash. White, crystalline powders water-soluble and possessing valuable cleansing and purifying properties. Prepared in various strengths. 

Alkalinity is the capacity of a water to accept protons and is the sum effect of all bases present, In most potable waters the alkalinity is due chiefly to bicarbonate ion and, to a minor extent, carbonate, ion. Carbonate alkalinity is defined as HCO3 + 2C03. Hydroxyl, when present (usually unimportant below about pH 10), is called caustic alkalinity. The conventional definition of total alkalinity Cg) in eq/L or meq/L, is... 

For over a century this definition sufficed. It was, nevertheless, unsatisfactory, being neither more nor less than a confession of ignorance and impotence. Thus it demanded that caustic potash should be regarded as an element until Davy succeeded in decomposing it by electrolysis in 1807. Similarly lime was regarded as an element and when Charles Tennant chlorinated slaked lime in 1799, the product was perforce called chloride of lime, a name that clings to it even to-day. 

Initial economic comparison of the dissociation-extraction type process with the chemical-consuming process of caustic wetsh, acidification, euid solvent extraction indicates that the dissociation extraction process, which has lower operating costs but may have higher capital cost for contactors and ctssociated equipment, may be less costly overall. A process optimisation cuid more detciiled economic assessment would have to be made, however, before a definite decision could be made between the two processes. 

Corrosives are the largest class of chemicals used by industry, so it stands to reason that they would frequently be encountered in transportation and at fixed facilities. DOT Class 8 materials are corrosive liquids and solids. There are no DOT subclasses of corrosives. There are, however, two types of corrosive materials found in Class 8 acids and bases. Acids and bases are actually two different types of chemicals that are sometimes used to neutralize each other in a spill. They are grouped together in Class 8 because the corrosive effects are much the same on tissue and metals, if contacted. It should be noted, however, that the correct terminology for an acid is corrosive and for a base is caustic. DOT, however, does not differentiate between the two when placarding and labeling. The DOT definition for a corrosive material is a liquid or solid that causes visible destruction or irreversible alterations in human skin tissue at the site of contact, or a liquid that has a severe corrosion rate on steel or aluminum. This corrosive rate on steel and aluminum is 0.246 inches per year at a test temperature of 131 F. ... 

A slightly different but equivalent definition of acids and bases is suggested by these equations. The first reaction results in an increase in hydronium ions (H O ). The second reaction results in an increase in hydroxide ions (OH ). Therefore, an acid can be defined as a chemical substance that, when added to water, results in an increase in the concentration of hydronium ions. A base is a chemical substance that, when added to water, results in an increase in the concentration of hydroxide ions. Hydronium ions give acid solutions the properties we associate with acids—sour taste, corrosiveness, and the ability to turn blue litmus paper red. Hydroxide ions give basic (or alkaline) solutions the properties of feeling soapy, causticity, and the ability to turn red litmus paper blue. 

The caustics such as sodium hydroxide in oven cleaners or drain cleaners are very toxic and corrosive. This kind of product will have definite instructions and warning labels that should be followed carefully. 

Synonyms Carboxylic acids, naphthenic Naphthenic acids Definition Any of a group of sat. higher fatty acids derived from gas-oil fraction of petroleum by extraction with caustic acid sol n. and subsequent acidification... 

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