Recovery of, from laboratory residues

The recovery of iodine from waste liquids.—E. Beilsteini2 recovered iodine from laboratory residues by evaporation to dryness with an excess of sodium carbonate and calcination until the organic matter is all oxidized. The mass is dissolved in sulphuric acid and treated with the nitrous fumes, obtained by treating starch with nitric acid, until all the iodine is precipitated. The iodine is washed in cold water, dried over sulphuric acid, and sublimed. Other oxidizing agents less unpleasant than the nitrous fumes employed by F. Beil stein—e.g. hydrogen peroxide—-were recommended by G. Torossian for the residues obtained in copper titrations. F. Beilstein s process is applicable to soluble but not to insoluble, oxidized forms of ioffine. F. D. Chattaway... 

Inorganic Syntheses, Volume XVIII Edited by Bodie E. Douglas Copyright 1978 by Joint Wiley Sons, Inc. 22, Recovery of Iridium from Laboratory Residues 131... 

Once method validation has been completed, the treated samples may be analyzed. The method should be under control so that no additional changes will be necessary. Analysis of laboratory-fortified samples and control samples will be used to monitor the quality of the study. The purpose of laboratory-fortified samples is confirmation of the recovery efficiency of residues from the sample matrix. A minimum of two laboratory recovery samples need to run with each set. Recoveries should average 70-120%. 

Under laboratory conditions, carbon dioxide in its supercritical state allows the separation of unstable compounds from the matrix. It is also used in industrial processes to extract certain food products (for example, decaffeination, recovery of aromas and spices, elimination of fats). Carbon dioxide has the advantage that it can be eliminated at rather low temperatures without leaving any toxic residue. However, the use of relatively high pressures creates potential hazards in industrial installations. 

It was demonstrated that the recovery of residues from the Chromosorb 104-Amberlite XAD-4 SPE column prepared in the laboratory was more... 

In the tenth official proficiency test, five laboratories did not find divinyl sulfoxide (CAS 1115-15-7) in the decontamination solution sample Dl The chemical should have been recovered from the organic extract of the sample. Concentration of the extract, if undertaken, could have helped two laboratories identify this chemical. In one laboratory, false sample preparation was the probable reason for missing it. The laboratory extracted the sample with dichloromethane, evaporated the extract to dryness, dissolved the evaporation residue, and finally sily-lated it. Usually, organic solvents should not be evaporated to dryness in the recovery of a volatile chemical, and this might be the reason for missing the chemical. Perhaps for this same reason the laboratory missed ethyl 2-methoxyethyl methylphospho-nate (CAS 170082-62-9) in the Dl sample. 

The aqueous process portion of this paper describes attempts to improve the recovery of americium. The first part deals with modifications to the cation exchange step the second describes development of a solvent extraction process that will recover americium from residues containing aluminum as well as other common impurities. (The anion exchange process cannot partition americium and aluminum.) Results of laboratory work are described. 

The relationship between capillary nnmber and residual oil saturation is well established, as reviewed by Stegemeier (1977) and Lake (1989). It is known that to obtain a substantial decrease in residual oil saturation at a micro scale in cores, the capillary number needs to be increased to two or three orders of magnitude above typical waterflood values, but the increase in polymer flood is usually less than 100. Therefore, it was believed that polymer flooding did not reduce residual oil saturation in a micro scale. However, the recovery factors from natural and artificial consolidated cores in the laboratory and in fields were generally higher when polymer flooded than waterflooded, as reviewed by Huh and Pope (2008). 

The following procedure, modified from Gilchrist s method, is intended for the recovery of platinum from residues containing base metals and noble metals (other than those of the platinum group) as well as strong com-plexing agents. A preliminary separation of base metals as hydrated oxides considerably reduces the time required to obtain pme platinum by the precipitation of ammonium hexachloroplatinate(IV). The authors have tested the procedure both with actual laboratory residues and with syn-... 

Hazardous wastes from nonspecific sources - Examples of laboratory wastes that would fall in this category would be spent solvents, the residue resulting from distillation recovery of used solvents, materials left over from silk screening and electroplating procedures in electronic laboratories, and other sources of used chemicals. 

---