Process waste solutions

COMPOSITION OF ACTUAL AND SYNTHETIC ACTINIDE PROCESS WASTE SOLUTIONS... 

Complexation and stability of americium ions in various media, including solids used for waste storage, are of increasing importance because of americium occurrence in nuclear process waste. Solutions to the problems of long-term, safe storage of americium must be found. To answer such questions, an increase in the study of americium chemistry is to be anticipated. 

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. 

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... 

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. 

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... 

Solution A Inorganic acids, metal processing wastes. 

The U.S. Bureau of Mines-Reno Research Center is conducting research on the chemical treatment of process waste waters by ion elutriation for removing low levels of anions from cyanide solutions. This research has been coordinated with other centers for developing a waste water treatment system. 

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. 

Of the many radioactive and inert constituents in waste solutions, only Tc and lanthanides coextract with actinides into the Truex process solvent. Trivalent lanthanides follow Am and Cm when the latter are stripped with dilute HNO3 depending on the disposition of the americium and... 

During development of the Truex process, various monofunctional organophosphorus reagents [e.g., TBP DBBP (dibutylbutylphosphonate) HDEHP (di-(2-ethylhexyl)phosphoric acid)] were considered for removal of alpha-emitters from HNO3 waste solutions. Two typical flow sheets for the use of HDEHP and TBP are shown in Fig. 12.14. Because of the poor performance of these two extractants, the processes were complicated. Distribution ratios... 

Chemicals processed. Waste pesticide solutions were collected after spray operations during late May, June, and July of 1983, and consisted primarily of three compounds 2,4-D [(2,4-dichloro-phenoxy)acetic acid], atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)- -triazine) and paraquat (1,1 -dimethyl-4,4 -bipyridinium dichloride). Our efforts were primarily directed at these pesticides, which are shown in Table I together with their formulations and concentrations. 

The technology developer, Atomic Energy of Canada Limited (AECL), has compiled cost estimates (in 1994 U.S. dollars) for the CHEMIC process based on treatment of a simulated waste solution contaminated with metals (cadmium and lead at feed concentrations from 1 to 5 mg/liter) and strontium-90 [from 1000 to 2000 becquerel per liter (Bq/liter)]. The target treatment level is <0.014 mg/liter lead, <0.02 mg/liter cadmium, and <10 Bq/liter strontium-90. See Table 1 for estimates associated with this cost analysis. The AECL analysis indicated that costs of the CHEMIC process compared favorably with the estimated costs for treatment using reverse osmosis or fixed-bed ion exchange. 

This technology can treat both acidic and basic solutions. It has the ability to remove organics, inorganics, radionuclides, and heavy metals from contaminated aqueous streams and is capable of treating process wastes and mixed wastes as well. 

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