Waste solutions

Concentrated waste solutions are obtained from spent metal plating baths and etchants. However, the majority of metal wastes are soflds or sludges obtained from the hydrolysis of metal-bearing solutions and industrial process effluents. Most of these water-insoluble wastes are composed of hydroxides or basic salts of the contained metals. Eor processing by hydrometallurgical routes the materials must be brought into solution usually by acid or ammoniacal or alkaline digestion. 

There are many common misconceptions about vinyl. Eor example, the idea that vinyl is not recycled is untme. Industrial scrap vinyl has been recycled for years, but in more recent years, post-consumer vinyl recycling is growing, too, with about 3.25 x 10 tons (6.5 x 10 lb) of post-consumer vinyl (primarily botdes) being recycled in the 1990s. When the Council for SoHd Waste Solutions (now the American Plastics Council) conducted a nationwide survey in 1991, it found that there were an estimated 1100 municipal recycling programs in place or plaimed in the United States that include vinyl. 

In the present time our organosilicon adsorbents found the practice application in such as fields such as, for example 1) the method of spectral-chemical determination of gold Clarke quantities in poor ores and rocks has been applied in analytic practice of geological establishments and research institutes 2) at the first time soi ption process was used in hydro-chemical analyze of fresh water. This method has been allowed to analyze of Baikal water 3) for purification metallurgical waters and waste solutions of chemical-metallurgical plants due to toxic elements 4) for creation the filters for extraction of rare elements, for example, uranium 5) for silver utilization from wasted of cinema-photo manufactory. This method has been applied to obtain the silver of high purity. 

Another example in the polymers industry is illustrated in Figure 17, which is a process aimed at the batch drying of waste residue with solvent recovery. In this application liquid or viscous waste solutions are pumped into a batch dryer where they are dried under vacuum to a solid granular residue. Vaporized water and solvent are recovered by condensation and then separated by gravity. The process scheme is flexible, offering a range of temperatures and vacuum levels for treating... 

Boyd, T. E. Kochen, R. L. Ferrite Treatment of Actinide Waste Solutions A Preliminary Study, U.S. DOE Rept. RFP-3299, Rockwell International, Golden, Colorado, July 30, 1982. 

A ferrite waste treatment process is being investigated to determine if it can more effectively remove actinides from waste solution with less solid waste generation than the flocculant precipitation method presently used (18). 

Rather than focus on specific incineration technologies, one must address the fundamental physical and chemical processes common to many of the possible incineration systems through studies of (1) reaction kinetics of selected waste materials and (2) behavior of waste solutions, slurries, and solids in the incineration environment. 

Aqueous waste solutions should be disposed of properly, and in particular solutions carrying heavy metals need to be treated. Untreated solutions, if released, can contaminate the geological environment. 

Quartz (Si02) and other silicates are generally stable in acidic solutions but will dissolve in highly alkaline waste solutions, decreasing the pH of the waste. The process by which this reaction occurs is complicated because it creates complex mixtures of nonionic and ionic species of silica. Scrivner and colleagues39 discuss these reactions in some detail. They observe that the silicates in solution buffer the liquid. Also, laboratory experiments in which alkaline wastes have been mixed... 

Metabolic Effects. Severe metabolic acidosis developed in a worker exposed to hydrogen sulfide generated from a sodium sulfide waste solution being dumped onto acid waste material (Stine et al. 

In closing, recovery of technetium from waste solution should be touched upon. Studies of the base hydrolysis of technetium P-diketone complexes revealed that all of the complexes studied decompose in an alkaline solution even at room temperature, until technetium is finally oxidized to pertechnetate. These phenomena are very important for the management of technetium in waste solutions. Since most metal ions precipitate in alkaline solution, only technetium and some amphoteric metal ions can be present in the filtrate [29]. A further favorable property of pertechnetate is its high distribution coefficient to anion exchangers. Consequently, it is possible to concentrate and separate technetium with anion exchangers from a large volume of waste solution this is especially effective using an alkaline solution [54],... 

The use of excess formic acid to destroy excess nitric acid (5M) in nuclear fuel reprocessing waste solutions at 100°C is potentially hazardous because of an induction period, high exothermicity and the evolution of large amounts of gas, mainly... 

It is also important to ensure that the pH of the final waste solution remains basic. If the pH is below 7, fluoride ions can react with methylphosphonate diesters, a common impurity in these agents, to regenerate the nerve agent. 

Tatsumoto, H. and T. Hattori. 1988. Appearance of cyanide from waste solutions containing no cyanides. Environ. Technol. Lett. 9 1431-1435. 

Table 17. Data illustrating the operation of the EleetroCell ER cell for the removal of metal ions from waste solution streams [79]...

AU waste solutions from the reaction were collected and disposed with hydrogen peroxide. 

During recycling of the fuel technetium follows the majority of the other fission products into the waste solutions. After storage for several years, the level of the radioactivity in the waste solutions has fallen sufficiently to allow the extraction... 

Table 3. Compositions of typical metal recovery waste solutions ...

Fig. 2. Schem of the extraction of technetium from a waste solution using pyridine ...

All waste solutions are flushed into the heating water bath so this instrument can be used for only the aqueous steps in immunostaining. Deparaffinization and hydration of slides must be done manually, prior to loading slides onto the Stainer. 

The future will bring further increase in concern over the environmental impact of chemical operations. The liquid effluents must not only be controlled, they must also be rendered harmless to the environment. This requires removal of the hazardous substances. For many of the dilute waste solutions, solvent extraction has proved to be an effective process. This is even more true for recycling of mixed metals from various industries. Nevertheless, the increasing amounts of wastes from human activities require much more to be done in this field. 

Large-scale winning of copper by acidic leaching of copper ores sometimes results in waste solutions containing appreciable amounts of uranium. The uranium bearing aqueous raffinate from copper extraction is usually a dilute sulfuric acid solution. Uranium can be recovered using the same technique as described in section 12.3.1. A typical example is uranium production at the Olympic Dam mine in Australia, where the copper ore bodies are estimated to contain a total of over a million metric tons of uranium. 

SOLVENT EXTRACTION OF ACTINIDES FROM WASTE SOLUTIONS... 

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