Vanadate , potassium salts

Vanadate, dioxybis(oxamato)-bond-length ratios, 1,57 Vanadate, heptacyano-potassium salt structure, I, 72 Vanadate, hexafluoro-dipotassium salt history, I, 21 potassium salt history, 1,21 tripotassium salt history, 1,21 Vanadate, pentachloro-stereochemistry, 1,40 Vanadate, pentafluorooxy-stereochemistry, I, 50 Vanadates biochemistry, 3,456 calcium/magnesium ATPase inhibition, 6, 567 competition with phosphates physiology, 6,665 protonation, 3,1026 sodium pump, 6, 557 in uranium purification from ore, 6, 899 Vanadates, hexafluoro-, 3. 482,531 Vanadates, oxoperoxo-, 3,501 Vanadates, pentacarbonyl-, 3, 457 Vanadium biology, 6,665 determination, 1. 548 extraction... 

VANADIC ACID, AMMONIUM SALT see ANY250 VANADIC ACID, MONOSODIUM SALT see SKPOOO VANADIC ACID, POTASSIUM SALT see PLK810 VANADIC(II) ACID, TRISODIUM SALT see SIY250 VANADIC ANHYDRIDE see VDUOOO VANADIC OXIDE see VEAOOO VANADIO, PENTOSSIDO di (ITALIAN) see VDUOOO VANADIUM see VCPOOO... 

EINECS 237-388-8 K-Van Potassium m-vanadate Potassium metavanadate Potassium trioxovanadate Potassium vanadate Potassium vanadate(V) (KVO3) Potassium vanadium trioxide UN2854 Vanadate (V03 ), potassium Vanadic acid, potassium salt. Crystals mp = 520" d = 2,840, Kerr-McGee. 

Vanadate, dioxybis(oxaraato)-bond-length ratios, 57 Vanadate, heptacyano-potassium salt structure, 72 Vanadate, hexafluoro-dipotassium salt history, 21 potassium salt history, 21 tripotassium salt history, 21... 

The use of biomass in fossil fuel based power plants is of increasing interest, since it is considered as a CO2 neutral fuel, having zero human impact on the eaibon release to the atmosphere. Simultaneously, eontinuous efBdent selective catalytic reduction of NO with ammonia (NH3-SCR) remains a very important condition for the implementation of biomass fuel as a sustainable alternative for energy production. However, the NH3-SCR catalyst suffers from a number of deactivation phenomena when installed in boiler units based on biomass combustion, due to exposure to potassium containing fly ash[l]. The active V=0 and V-OH sites on the commercially used V205-W03/Ti02 based catalyst reacts with the potassium salts and form inactive alkali vanadates, which are unable to adsorb ammonia. 

The active phase, which is soHd at room temperature, is comprised of mixed potassium and sodium vanadates and pyrosulfates, whereas the support is macroporous siUca, usually in the form of 6—12 mm diameter rings or pellets. The patent Hterature describes a number of ways to prepare the catalyst a typical example contains 7 wt % vanadium pentoxide, 8% potassium added as potassium hydroxide or carbonate, 1% sodium, and 78 wt % siUca, added as diatomaceous earth or siUca gel, formed into rings, and calcined in the presence of sulfur dioxide or sulfur trioxide to convert a portion of the alkah metal salts into various pyrosulfates (81,82). 

Sodium hexakis(formato)molybdate, 3, 1235 Sodium hypochlorite alkene epoxidation manganese catalysts, 6,378 Sodium ions biology, 6, 559 selective binding biology, 6, 551 Sodium molybdate, 3, 1230 Sodium peroxoborate, 3,101 Sodium/potassium ATPase, 6, 555 vanadate inhibition, 3, 567 Sodium pump, 6, 555 mechanism, 6, 556 Sodium pyroantimonate, 3, 265 Sodium salts... 

As examples of some water-soluble salts, mention may be made of potassium chloride, copper sulfate, and sodium vanadate. As examples of some water-insoluble salts, mention may be made of some typical ones such as lead chloride, silver chloride, lead sulfate, and calcium sulfate. The solubilities of most salts increases with increasing temperature. Some salts possess solubilities that vary very little with temperature or even decline. An interesting example is provided by ferrous sulfate, the water solubility of which increases as temperature is raised from room temperature, remains fairly constant between 57 and 67 °C, and decreases at higher temperatures to below 12 g l-1 at 120 °C. Table 5.2 presents the different types of dissolution reactions in aqueous solutions, and Table 5.3 in an indicative way presents the wide and varied types of raw materials that different leaching systems treat. It will be relevant to have a look at Table 5.4 which captures some of the essential and desirable features for a successful leaching system. 

Cone, aqua ammonia in the cold dissolves carbamate from the commercial carbonate, and it converts the hydrocarbonate into normal carbonate-either by removing half its carbonic monohydride, or by combining with it and with water. If the commercial carbonate be digested with a sat. soln. of ammonia in a closed vessel at 20° to 25°, this salt slowly dissolves, and the soln., on cooling, deposits crystals of ammonium carbamate and a little normal carbonate (NH3)3H20(C02)2-j-NH3 =H20+2C02(NH3)2. C. Arnold has tabulated the solubilities of the freshly precipitated carbonates and hydroxides of most of the common metals in sat. soln. of potassium and ammonium carbonates. A. Ditte studied the action of soln. of ammonium carbonate on vanadic oxide. 

Potassium Vanadicyanide, K3[V(CN)6], is prepared by the addition of excess of concentrated potassium cyanide solution to a concentrated solution of vanadous chloride, VC18 precipitation in the cold with alcohol gives rise to small rhombohedral plates. The solution is not very stable and rapidly becomes turbid, while addition of an acid produces the green colour which is characteristic of the V ion. The complex ion [V(CN)8]" appears, therefore, to be unstable, unlike the corresponding [Fe(CN)e] ", [Cr(CN)J ", and [Co(CN)e] " complex ions. The solution reacts with salts of heavy metals to yield variously coloured precipitates of double cyanides.7... 

Estimation of Vanadium.1—Volumetric Methods.—The most convenient and the usual method for the estimation of vanadium is a volumetric process. The vanadium is first obtained in acid solution as vanadate, and reduced to the tetravalent state by one of several reducing agents which are available. The solution is then titrated in the presence of sulphuric acid with hot potassium permanganate solution, which quantitatively oxidises the lower vanadium salt to the vanadate. Using sulphur dioxide to effect the reduction, the following reactions take place —... 

The estimation of a vanadate solution by direct titration with ferrous sulphate or ferrous ammonium sulphate solution has been worked out, and is found to be specially applicable to the analysis of vanadium alloys. The vanadate is again reduced to tire tetravalent state by the ferrous salt, the end point being obtained by the use of potassium ferricyanide as internal indicator alternatively, a known excess of the ferrous salt solution is added to the vanadate, the amount unused... 

A general method for the separation of vanadium from arsenic, molybdenum, phosphorus, chromium, uranium, tungsten, and silicon, consists in precipitating these metals as their respective lead salts and digesting the precipitate with potassium carbonate, whereupon all the lead salts are decomposed with the exception of the lead vanadate.5... 

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