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<br />excess KASTONE" to shorten reaction time (which is <br />normally about'fz-t hour at ambient temperature). Dilu- <br />tion and controlled addition rate may be needed when <br />treating more concentrated wastes. <br />Advantages of the KASTONE~ process vs. the chlori- <br />nation process include: <br />• The reagents are far less corrosive. <br />• Investment is usually substantially lower. <br />• Operating costs are frequently lower. <br />• Cyanogen chloride and chlorinated by-products <br />are not produced. <br />• More concentrated cyanide wastes can be treated <br />safely. <br />• The hazards of handling chlorine are avoided. <br />ammonia that will be generated. The most effective and <br />widely used chemical methods to destroy cyanide are <br />owdizing it to cyanate (CNO-) wdh hypochlorite or hy- <br />drogen peroxide. Both methods are effective for oxidiz- <br />ing free cyanide, ions, or loosely bonded complexes. <br />Metal Complexes <br />Strongly bonded metal cyanides, especially iron <br />cyanides (ferro- and ferricyanide), are apt to be found in <br />cyanide waste streams. These will not be detected by <br />simple analytical procedures, such as titration with silver <br />nitrate, that are normally used fcr measuring cyanide <br />concentration. However, they wi l be included in the <br />"total cyanide" analyses using acid distillation proce- <br />dures. These complexes are not effectively destroyed <br />by the commonly used waste processes. If regulations <br />re uire removal of these enerall stable com lexes f <br />ow toxicity, other treatment methods suc as preci ita- <br />ton to pro uce a so i was a may a regwred. <br />By-products from KASTONE® treatment are cyanate, <br />ammonia, and glycolic acid amide. cyanate does not <br />revert to cyanide in surface waters or sewage treatment <br />systems according to a U.S. Public Health Service <br />study. Both the cyanate and glycolic acid amide are <br />biodegradable. The cyanate can be readily hydrolyzed <br />in acid solutions to ammonia. <br />Hydrolysis <br />Hydrolysis is sometimes a practical treatment for strong <br />sodium cyanide solutions. Simply boiling a 70% sodium <br />cyanide solution for about 8 hours should reduce the <br />cyanide content to the parts per million range where <br />chemical oxidation can be used more effectively. Provi- <br />sions should be made, of course, to accommodate the <br />HANDLING SPILLS <br />Sodium cyanide spills should be cleaned up promptly to <br />minimize exposure to people and the environment. <br />Shovel and sweep spilled materia' into a drum or suit- <br />able container. Keep spilled material dry. If raining, <br />covering the spill will reduce the solution of sodium <br />cyanide and reduce run-off. Decontamination of an area <br />and destruction of cyanide for disposal can be accom- <br />plishedwith dilute hypochlorite solution. A small amount <br />of caustic (5 Ib/100 gallons water) Nill keep the pH of a <br />sodium cyanide solution around 12 and minimize hy- <br />drogencyanide formation. A little caustic solution can be <br />used in a wet drum or puddle until disposal or decon- <br />tamination is completed. <br />19 <br />