Recovery wastes

Technologies to minimize resource consumption, to promote waste recovery and to develop clean processes and products... 

As in all the processes, the process condensate and all other sources of waste urea—NH —water contamination go to a waste recovery unit which includes a urea hydrolyzer. The final water discharge is then below 3—5 ppm of NH and urea. 

The depressed prices of most metals in world markets in the 1980s and early 1990s have slowed the development of new metal extraction processes, although the search for improved extractants continues. There is a growing interest in the use of extraction for recovery of metals from effluent streams, for example the wastes from pickling plants and electroplating (qv) plants (276). Recovery of metals from Hquid effluent has been reviewed (277), and an AM-MAR concept for metal waste recovery has recentiy been reported (278). Possible appHcations exist in this area for Hquid membrane extraction (88) as weU as conventional extraction. Other schemes proposed for effluent treatment are a wetted fiber extraction process (279) and the use of two-phase aqueous extraction (280). 

Illinois Power and Waste Recovery, Inc. (WRI), the largest producer of IDE in the United States, entered into an agreement under which WRI will supply I DE to Illinois Power s Baldwin station. Beginning in late 1994, about 3% of the coal was replaced with tires. This requires 70,000 tons of I DE per year, or the equivalent of seven million passenger tires, and represents - 60% of the scrap tires generated in Illinois each year. 

Waste Recovery, Inc. (WRJ) shreds tires for fuel at installations in Pordand, Oregon Adanta, Georgia MarsiU.es and Du Po, Illinois Conshohocla, Peimsylvania and Houston, Texas. Goodyear owns - 10% of WRJ. Firestone bums rejected tires in addition to other soHd wastes. 

Cheremisinoff, N. P. and P. N. Cheremisinoff, Water Treatment and Waste Recovery Advanced Technologies cmdApplication, Prentice hall Publishers, New Jersey, 1993. 

Figure 21.7.1 Pyrolysis and waste recovery section of an etliylene production plant.

MCI2 -f H2O (especially for removal of impurities or waste recovery)... 

Figure 2. Aqueous waste recovery and treatment processes (broken lines represent processes under development).

Waste Treatment. Figure 2 outlines the current waste recovery and treatment processes, and proposed changes. Acid waste streams are sent through nitric acid and secondary plutonium recovery processes before being neutralized with potassium hydroxide and filtered. This stream and basic and laundry waste streams are sent to waste treatment. During waste treatment, the actinides in the aqueous waste are removed by three stages of hydroxide-iron carrier-flocculant precipitation. The filtrate solution is then evaporated to a solid with a spray dryer and the solids are cemented and sent to retrievable storage. 

This paper analyses the difficulties of the two traditional plastics waste recovery routes, energy recovery and mechanical recycling, and goes on to introduce a third... 

Figure 1. Key elements of the TAP reactor (A) and high pressure fixed bed reactor (B) experimental systems. The TAP reactor schematic shows the heated valve manifold and reactor with the elevated pressure attachment located in the main high vacuum chamber. The fixed bed reactor shows the feed system, liquid vaporizer, oxygen disperser, reactor, and waste recovery system.

The electrostatic separation method is the exclusive choice in some specific situations, for example in the cases of rutile and ilmenite deposits. These deposits generally contain minerals of similar specific gravities and similar surface properties so that processes such as flotation are unsuitable for concentration. The major application of electrostatic separation is in the processing of beach sands and alluvial deposits containing titanium minerals. Almost all the beach sand plants in the world use electrostatic separation to separate rutile and ilmenite from zircon and monazite. In this context the flowsheet given later (see Figure 2.35 A) may be referred to. Electrostatic separation is also used with regard to a number of other minerals. Some reported commercial separations include those of cassiterite from scheelite, wolframite from quartz, cassiterite from columbite, feldspar from quartz and mica, and diamond from heavy associated minerals. Electrostatic separation is also used in industrial waste recovery. 

Waste recovery and/or reuse. This comprises the identification and implementation of opportunities to recover process chemicals and materials for direct reuse or for reuse elsewhere through renovation or conversion technology. 

Rickies, R.N. Waste Recovery and Pollution Abatement, Chemical Engineering, Sept. 27,1965,... 

MAWR [Mobil alkanolamine waste recovery] A process which reduces the quantity of waste generated by alkanolamine processes, which remove acid gases from oil refinery gas streams. Developed by Mobil Oil, Germany, and used commercially there since 1979. 

WASTE RECOVERY PROCESSES INVOLVING SOLVENT EXTRACTION... 

Although the problem of disposal of large amounts of metal waste is faced by most industrialized countries, relatively few centrally located operations for waste recovery have, to date, been started. Sweden still deposits its dewatered metal waste in a simple landfill, although Swedish industry has been in the forefront of developing both hydrometallurgical and pyrometallurgical recovery techniques. The same applies to most European countries however, interest in environmentally safe recovery has increased in recent years and recovery plants are now being considered. 

In general, for the centrally located facility, direct investment is high and the decision time for the investment usually drastically increases with the size of operation. Big investment, a relatively low return, the unstable value and uncertain situation of feed materials (raw material or waste), and, finally, fluctuating prices of end products characterize a metal waste recovery process. These facts indicate the necessity of financial support from government to secure the realization of such a project. 

Recovery of sodium sulfate from waste is an important waste control strategy within synthetic organic pharmaceutical plants. A sodium sulfate waste recovery system was employed... 

Leidner, J. Plastics Waste. Recovery of Economic Value Dekker iJew Tfork, 1981. 

This book outlines the basic principles needed to understand the mechanism of explosions by chemical explosives. The history, theory and chemical types of explosives are introduced, providing the reader with information on the physical parameters of primary and secondary explosives. Thermodynamics, enthalpy, free energy and gas equations are covered together with examples of calculations, leading to the power and temperature of explosions. A very brief introduction to propellants and pyrotechnics is given, more information on these types of explosives should be found from other sources. This second edition introduces the subject of Insensitive Munitions (IM) and the concept of explosive waste recovery. Developments in explosive crystals and formulations have also been updated. This book is aimed primarily at A level students and new graduates who have not previously studied explosive materials, but it should prove useful to others as well. I hope that the more experienced chemist in the explosives industry looking for concise information on the subject will also find this book useful. 

Byszewski, C., and Mani, K.N. September 1989. "A Technology For Metal Waste Recovery." Metal Waste Management Alternatives Symposium Proceedings. California Department of Health Services, Alternative Technology Section. 

The latest projects to eliminate the production of waste treatment sludges were undertaken in the wet process metal plating production area. The projects, completed in March 1989, involved the installation of separate cadmium, chrome, copper and nickel recovery systems. All of the recovery systems utilized redundant conventional ion exchange columns for initial metal waste recovery and concentration. 

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