Caustic soda treatment

The presence of biosurfactants in that bioliqour appear to render favorable results in terms of decreasing the amount of wastes and conditions employed in conventional processes, such as caustic soda treatment. In comparison, lower temperatures and no need of caustic soda are clear advantages, and consequently the present invention is said to avoid the production of clay dispersion sludges. 

The substrate also has an important influence on diffusion of the dye. The diffusion rate increases with caustic soda treatment or mercerization of cotton. However, with regenerated cellulose fibers, which have a marked skin-core structure, the outer parts of the fiber can act as a diffusion barrier. 

The purification of the liquid alkylate from the reaction system is done in a conventional fashion (Figure 5). Before feeding the crude ethylbenzene to distillation, the aluminum chloride and the residual HCl must be completely removed. Water washing accomplishes most of this task final traces are removed by a caustic soda treatment. This process is completely reliable, is free from emulsion formation, and there is no downstream fouling or corrosion to worry about. 

While several laboratories have shown that severe racemiza-tion of proteins can occur during treatment with sodium hydroxide (6,18,22-24,61,62) the effects of other alkalis used in food processing are documented less well. Jenkins, et al. (70) have observed substantial differences in the degree of racemization caused by lime or caustic soda treatment of zein. Lime causes only 50% to 90% of the racemization observed for several amino acyl residues compared to when caustic soda is used. Because a substantial amount of calcium ion remained bound to the protein (approx. 10,000 ppm) compared to l/20th that amount of sodium ion for the caustic soda-treated zein, it is possible that divalent calcium may stabilize the protein making it less susceptible to racemization. Tovar (14) observed increases of 40% to 50% in serine and phenylalanine racemization and a decrease of 30% aspartate racemization for caustic soda-treated fish protein concentrate compared to lime-treated protein (see Table II). These studies indicate that different alkalis have different effects on racemization of proteins specifically, lime may cause less racemization than caustic soda at a similar pH. 

From these results, it can be concluded that caustic soda treatment is much more deleterious to zein than is lime treatment. Racemization of 9 of 11 amino acids in the caustic soda-treated zein was equal of or higher than that observed for the lime-treated protein (70). However, the mechanism by which nutritional quality is reduced is not clear. In a related study, Schwass, et al. investigated lime and caustic soda effects on pronase digests of treated zein, and observed similarly reduced levels of uptake of both treated materials by perfused rat jejunum (16). Therefore, the reduced nutritional quality of caustic soda-treated zein observed by Tovar (14) may be due to impaired metabolic utilization at a step subsequent to intestinal absorption. 

Bhattacharya and Shah [26] studied the influence of environment-friendly enzyme treatment of flax fabrics using BGLU enzyme with hemicellulase and pectinase activities. Under optimal conditions of enzymalysis, weight loss was in the region of 12%, similar to that obtained by conventional caustic soda treatment (10 16%). In addition, the fabrics had improved absorbency, whiteness, and dyeability with tolerable loss of tensile strength. 

Bhattacharya and Shah [26] found enzymatic treatment to be more beneficial compared with the conventional caustic soda treatment for removing noncellulosics from flax fabrics. The dye uptake of both direct (124.7%) and reactive dyes (106.2%) appears to increase with enzymatic treatment relative to conventional caustic soda treatment. 

The operations in the Mt. Isa primary refinery have been covered by previous papers (2,6). The Mt. Isa bullion is produced by a conventional sinter plant/lead blast furnace operation. The resulting crude bullion is decopperised to less than 0.003 % Cu and is then given a caustic soda treatment to remove arsenic to less than 0.003%, prior to casting into 4-tonne slabs. This impure lead is shipped by railroad to Townsville and then by sea in 12,000- to 14,000-tonne shipments to BRM for further processing. 

Where high purity concentrates are processed and only minor amounts of copper have to be removed, one method used at the Naoshima smelter in Japan is to add aluminium to form the intermetallic compound CUAI2. Aluminium is added as a 40 per cent alloy with zinc because of its low melting point at 560°C compared with aluminium at 660°C. Zinc is removed from the lead later either in the dezincing process or by caustic soda treatment. This method produces a dry powdery dross, which is easily handled and can reduce copper levels to less than one gram per tonne (Moriya, 1989). 

The effect of scouring with enzymes was compared to conventional caustic soda treatment and solvent extraction. Whereas caustic soda treatment resulted in the highest deterioration on a molecular level, but led to a high level of whiteness, the solvent-extracted samples showed superior tensile strength and the bioscoured samples the best softening effect. ... 

Uses Mercerizing assistant for textiles suitable for caustic soda treatment Properties Liq. 

Brine Treatment. The principal use of aqueous HCl is for the acidification of brine prior to feeding it to the electrolytic cells for producing chlorine and caustic soda. Almost all of this HCl comes from captive sources. An estimated 213 thousand metric tons of HCl (100% basis) was used for brine treatment in 1993 (74). 

Regulations. In order to decrease the amount of anthropogenic release of mercury in the United States, the EPA has limited both use and disposal of mercury. In 1992, the EPA banned land disposal of high mercury content wastes generated from the electrolytic production of chlorine—caustic soda (14), accompanied by a one-year variance owing to a lack of available waste treatment faciUties in the United States. A thermal treatment process meeting EPA standards for these wastes was developed by 1993. The use of mercury and mercury compounds as biocides in agricultural products and paints has also been banned by the EPA. 

The common treatment methods are acidification, neutralization, and incineration. When oxahc acid is heated slightly in sulfuric acid, it is converted to carbon monoxide, carbon dioxide, and water. Reaction with acid potassium permanganate converts it to carbon dioxide. Neutralization with alkahes, such as caustic soda, yields soluble oxalates. Neutralization with lime gives practically insoluble calcium oxalate, which can be safely disposed of, for instance, by incineration. 

The Hquid from spent caustic soda baths must be disposed of or treated as a ha2ardous waste. The finish residue may contain heavy metals as well as caustic thus requiring treatment as a ha2ardous waste. 

Alkali Treatment. Caustic washing is the treatment of materials, usually products from petroleum refining, with solutions of caustic soda. The process consists of mixing a water solution of lye (sodium hydroxide or caustic soda) with a petroleum fraction. The treatment is carried out as soon as possible after the petroleum fraction is distilled, since contact with air forms free sulfur, which is corrosive and difficult to remove. The lye reacts either with any hydrogen sulfide present to form sodium sulfide, which is soluble in water, or with mercaptans, foUowed by oxidation, to form the less nocuous disulfides. 

Removal of Free Fatf Fields. Alkali treatment of the oil is accompHshed by the use of caustic soda solutions to neutralize the excess free fatty acids. Because castor oil readily forms emulsions with water and/or alkaline solutions, special techniques have been developed to neutralize the acids. A continuous counter-current process was developed using a stationary contact reactor (15). Treatment in the presence of a solvent is also utilized (16). 

Ethylene Propylene (EP, EPDM) is an o-ring rubber compound that is compatible with most water-based chemicals. It is good with caustic soda, detergents, water treatment chemicals, steam, and wastewater and with food processes like milk, beer, and soups. EP rubber compound is petroleum based and for this reason it should never come into contact with petroleum based chemicals. 

The monomer is produced from trichloroethane by dehydrochlorination Figure 17.2). This may be effected by pyrolysis at 400°C, by heating with lime or treatment with caustic soda. The trichlorethane itself may be obtained from ethylene, vinyl chloride or acetylene. 

Health Hazards Information - Recommended Personal Protective Equipment Maximum protective clothing goggles and face shield Symptoms Following Exposure Severe bums caused by burning metal or by caustic soda formed by reaction with moisture on skin General Treatment for Exposure SKIN brush off any metal, then flood with water for at least 15 min. treat as heat or caustic bum call a doctor Toxicity by Inhalation (Ihreshold limit Value) Not pertinent Short-Term Exposure Limits Not pertinent Toxicity by Ingestion Not pertinent Late Toxicity None Vtqtor (Gas) Irritant Characteristics Non-volatile Liquid or lid Irritant Characteristics Severe skin irritant. Cause second- and third-degree burns on short contact and is very injurious to the eyes Odor Threshold Not pertinent. 

Anhydrous caustic soda (NaOH) is available but its use is generally not considered practical in water and wastewater treatment applications. Consequently, only liquid caustic soda is discussed here. Liquid caustic soda is generally shipped at two concentrations, 50 percent and 73 percent NaOH. The densities of the solutions as shipped are 12.76 Ib/gal for the 50 percent solution and 14.18 Ib/gal for the 73 percent solution. These solutions contain 6.38 Ib/gal NaOH and 10.34 Ib/gal NaOH, respectively. The crystallization temperature is 53 F for the 50 percent solution and 165 F for the 73 percent solution. The molecular weight of NaOH is 40. The pH of a 1 percent solution of caustic soda is 12.9. 

A plant worker opened the hatch of a reactor and manually charged it with caustic soda. However, he had failed to check the reactor prior to charging, and the caustic soda reacted with chemicals already present to release a toxic by-product. The worker was overcome, and only survived following emergency treatment. 

This ketone, of the formula Cj H O, isomeric with those above described, is found in the oils of thuja, tansy, wormwood, and sage. It is identical with the bodies formerly described under the names tan-acetone and salvone. It is best prepared in a state of purity from oil of wormwood. According to Semmler, 200 c.c. of the oil, 0 c.c. of a saturated solution of sodium bisulphite, 75 c.c. of water, and 300 c.c. of alcohol are well shaken at intervals during a fortnight. The crystals formed, consisting of the compound of thujone with the sodium bisulphite, are separated, washed with alcohol-ether, and pressed. On treatment with caustic soda solution, the thujone, amounting to over 40 per cent, of the oil used, separates, and can be distilled with steam. 

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