Sulfate Wastes

Fluorogypsum and phosphogypsum are sulfate-rich by-products generated during the production of hydrofluoric and phosphoric acid, respectively. Full descriptions of these wastes [196-206] are given in Table 10. 

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Important side reactions are the formation of ether and addition of alcohol to the acrylate to give 3-alkoxypropionates. In addition to high raw material costs, this route is unattractive because of large amounts of sulfuric acid—ammonium sulfate wastes. 

Paints. Paints account for perhaps 3% of sulfur consumption (see Paint). The main sulfur use is for the production of titanium dioxide pigment by the sulfate process. Sulfuric acid reacts with ilmenite or titanium slag and the sulfur remains as a ferrous sulfate waste product. Difficulties with this process have led to the development of the chloride process (see Pigments, inorganic Titanium compounds). 

Sulfat, n, sulfate, -ablauge, /. sulfate waste liquor, -anlage,/. sulfate plant. 

Universal treatment standards alpha-endosulfan beta-endosulfan endosulfan sulfate Waste water 0.023 mg/L 0.029 mg/L 0.029 mg/L 40 CFR 268.48, EPA 1999b... 

The environmental benefit of this route is evident when compared to the traditional methyl methacrylate manufacturing process, which uses hazardous hydrogen cyanide and produces stoichiometric amounts of ammonium hydrogen sulfate waste. 

Portland cement Sodium sulfate waste from sebacic acid production [1428]... 

Fersona A process for stabilizing the calcium sulfite/sulfate waste from FGD processes, so that it may be used for landfill. The waste is mixed with ferric sulfate waste from another process (e.g., metallurgical leaching) to form sparingly soluble basic sodium ferric sulfates. Developed in the 1970s at the Battelle Columbus Laboratories, OH, under contract with Industrial Resources. See also Sintema. 

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... 

Both of these processes direct the SO2 absorbed from the FCCU flue gas to the refinery SRU, where it is converted to elemental sulfur and added to the marketable sulfur that is generated by the SRU from H2S. Alternately, the SO2 can be converted to sulfuric acid in a dedicated sulfuric acid plant, or in combination with an existing refinery spent acid regeneration unit. When the SO2 is directed to the SRU, 1 ton of SO2 captured in the scrubber is converted to 0.5 tons of marketable elemental sulfur and less than 0.1 ton of sodium sulfate waste is generated per ton of SO2 absorbed. In an acid plant, 1 ton of SO2 generates 1.5 tons of 98% sulfuric acid. Steam is also generated from the conversion of SO2 in both the SRU and the acid plant, which moderates somewhat the steam consumption rate of the solvent regenerator for both the LABSORB and CANSOLV systems. 

Exchange resins may have an affinity for other ionic contaminants such as sulfates. Waste streams with these competing ionic contaminants may have lower removal efficiencies and these treatment systems may require more frequent resin regeneration or disposal. Ion exchange treatment does not destroy targeted contaminants. In some cases, waste disposal costs may render the technology cost prohibitive. 

Alternatively, sulfuric acid can be prepared from the iron(II) sulfate waste, which is obtained during the manufacture of Ti02 (equation 21). 

The first-cycle raffinate wastes produced at the ICPP are the acid aluminum waste from various test reactor fuels, fluoride-bearing waste from zirconium-matrix fuel, a small amount of stainless steel sulfate waste from fuel from developmental reactors such as the Organic Moderated Reactor Experiment (OMRE), acid stainless steel nitrate waste from the electrolytic dissolution of Experimental Breeder Reactor-II (EBR-II) reactor fuel, and an acid waste from the recovery of uranium... 

Mineral processing wastes MPW Amounts since early production are 50 billion t (55 billion T) 21 Sulfate wastes SW 900 million t (1 billion T)... 

Table 15 gives the different physical and chemical properties of both fluoro-gypsum and phosphogypsum [ 196-206]. These properties can affect the engineering uses and application of sulfate wastes on roadways and highways. 

Smith LM, Larew HG (1975) User s manual for sulfate waste in road construction. Federal Highway Administration, Report No FHWA-RD-76-11, Washington, DC,p 528... 

E. Curcio, X. Ji, A.M. Quazi, S. Barghi, G. Di F ofio, E. Fontananova, and T. Macleodd, E. Drioli, Hybrid nanofiltra-tion-membrane crystallization system for the treatment of sulfate wastes, J. Membr. Set 360 (2010) 493 98. 

Ferric sulfate Waste cooking oil Methanol 95 10 01 2h FFAs Ji et ah, 2006... 

Ferric sulfate Waste cooking oil Methanol 100 9 01 2h FFAs Patil et ah, 2010... 

E-Caprolactam (CL) is a very important monomer for the production of nylon-6, and about 4.2 million tons of CL were manufactured worldwide in 1998 [126]. Most current methods of CL production involve the conversion of cyclohexanone with hydroxylamine sulfate into cyclohexanone oxime followed by Beckmaim rearrangement by the action of oleum and then treatment with ammonia, giving CL. A serious drawback ofthis process is the co-production of a large amount of ammonium sulfate waste [126, 127]. Raja and Thomas reported a method for one-step production of cyclohexanone oxime and CL by the reaction of cyclohexanone with ammonia under high-pressure air (34.5 atm) in the presence of a bifunctional molecular sieve catalyst [128]. Hydrogen peroxide oxidation of cyclohexanone in the presence of NH3 catalyzed by titanium silicate is reported to produce CL [129]. In patent work, on the other hand, the transformation of l,l -peroxydicyclohexylamine (PDHA) to a 1 1 mixture of CL and cyclohexanone by LiBr has been reported [130]. 

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