Treating processes oxidation

Ni is found in many ores in combination with S, As Sb, the chief sources being the minerals chalcopyrite, pyrrhotite and pentlandite. Ni ores are of two types, sulfide and oxide, the former accounting for two-thirds of the world s consumption. Sulfide ores are refined by flotation and roasting to sintered Ni oxide, and either sold as such or reduced to metal, which is cast into anodes and refined electrolytically or by the carbonyl (Mond) process. Oxide ores are treated by hydrometallurgjcal refining, eg, leaching with ammonia. Much secondary Ni is recovered from scrap (Refs 6 7) 1... 

For Ti02 and Z1O2, it is well known that sulfation induces a strong increase of acidity [17] and the participation of an add mechanism could then account for this promotion of activity. This mechamsm can be described as a bifunctional process oxidation of NO to NO on Cu sites, and nitration of a product of the oxidation of decane on the acid fiinction(8). The preparation of the catalyst must have a great influence on the activity. This has been shown by the comparison of three Cu/TiC catalysts prepared in different conditions one in which titania is first treated with sulfuric acid, then by Cu acetate (denominated Cu 04/Ti02, containing 0.S wt% Cu, 0.6 wt% S), one in which Cu is... 

It safely treats process offgases using a combination of thermal treatment, catalytic oxidation, activated carbon filters, and treatment of the munitions demilitarization building (MDB) HVAC system ventilation air through activated carbon filter media prior to release. 

J. J. Berzelius made phosphorous acid by treating phosphorous oxide with water —a reaction studied by T. E. Thorpe and A. E. H. Tutton, vide supra. B. D. Steele obtained it by the action of iodine on hypophosphorous acid (q.v.) in the presence of mineral acids and A. Besson, by heating the hemioxide with water in a sealed tube at 100° P20+024-3H20=2H3P0k. Phosphorous acid is also produced by the action of hot dil. nitric acid oh phosphorus the objection to this process, said J. Come, is the simultaneous production of phosphoric acid (q.v.), and this the more, the greater the cone, of the nitric acid. T. Salzer, and J. Philipp also reported that some hypophosphoric acid is produced at the same time. The early workers knew that the aq. soln. of phosphatic acid slowly decomposes, giving off phosphine, hence the faint smell like garlic. C. F. Sehonbein mentioned that freshly prepared phosphatic acid contains a trace of nitric acid as well as ozone. A. Tamm also observed that some phosphorous acid is formed when phosphated steel is dissolved in nitric acid. 

Iodine is produced by similar methods, namely, oxidation of the iodide anion from brines by chlorine. However, iodine is also produced in a reductive process by reacting NalOs, extracted from the natural source of Chilean saltpeter, with sodium hydrogen snffite. The pentavalent iodine is reduced to iodide (equations), which is then treated and oxidized with a sufficient amonnt of the mother liquor to liberate elemental iodine (equation 5). In contrast to chlorine and bromine, which have large industrial uses, iodine has no predominant commercial use. 

A modification of the SFGD process just described is the Shell flue gas treating process, which not only removes sulfur oxides from flue gas, but can also effect a substantial reduction of the nitrogen oxides content. This is based on the activity of copper, whether in the oxidic or sulfate form, to catalyze the reaction of nitrogen oxides with ammonia according to the reactions... 

Particles of lead dioxide in lead monoxide, such as those formed in a ball-mill, can be formed by treating the oxide with ozone before paste mixing [49]. The use of persulfate [50-53] and peroxides [54] to effect the partial conversion of lead oxide in the paste to lead dioxide has also been proposed. A proprietary process for treating the surfaces of unformed plates with ozone gas produced a thin coating of lead dioxide, which enhanced formation [55,56]. Much lower quantities of lead dioxide are needed with this approach than when red lead is added to the plate, and the normal battery paste mix can be used. Dipping or spraying the plate with a persulfate solution has also been adopted to oxidize the surface PbO to conductive Pb02 [57]. 

M. G. Hyvert recommends the following process —Carbonate of soda is melted with a mixture of. antimony and saltpetre or sodium dioxide, and a solution of sulphate of alumina is used to treat the waters of lye-washing. Good results can also be obtained by treating antimony oxide, together with pulverised bauxite, with silicate of soda, the product being treated with lye-washing and... 

In this process, oxides of sulfur are absorbed in caustic soda. The reactions in the scrubber (29.4-29.7) produce soluble reaction products. The solution from the sump of the absorber is treated in a separate reaction vessel with lime (Fig. 29.2). 

The trick in this process centers on the fact that TiCU is a liquid with a boiling point (136.4°C), a little higher than that of water. The tetrachloride can be formed by treating the oxide (ratile) with chlorine gas at high temperature. The balanced equation is ... 

Liquid etchants can be used for chenucal modification or dissolving surface contamination. Etchants effectively treat irregularly shaped objects that are difficult to treat by other adhesion-promoting processes such as corona or flame treatment. A number of etching solutions and procedures have been developed for specific polymeric surfaces. The choice of the liquid etchant depends on the polymers. Polyolefins are usually treated by oxidizing acids such as chromic, sulfuric, nitric, or mixtures of these. Fluorocarbons are usually treated by sodium-napthalene etching solution. 

The process has already been realized in a pilot plant, ft is based on oxidation with hydrogen peroxide, which is added in the aqueous phase. The formic acid added as a catalyst must be stripped after oxidation and treated. The oxidation products are then extracted from the fuel with an aluminum oxide adsorbing agent. The adsorbing agent is purified with methanol, which in turn must be regenerated for reuse. 

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