Abstract: A process for removal of vanadium from wet process phosphoric acid comprising the steps of;(i) adsorbing an anionic pentavalent complex of vanadium, derived from the wet process phosphoric acid, onto an anion exchange resin or into an organic layer; and(ii) reducing the vanadium complex to trivalent and/or tetravalent vanadium so as to selectively strip vanadium from the anion exchange resin or from the organic layer.

Abstract: A method is described for converting formaldehyde to a gaseous product mixture capable of reacting with nitrogen oxide which comprises reacting formaldyhyde with nitrogen in the presence of a catalyst which is capable of promoting the reaction between formaldehyde and nitrogen at a temperature below about 1200.degree. F. The gaseous product mixture obtained in this manner is effective in reducing the nitrogen oxide content of combustion gases by mixing the gaseous product mixture with the combustion gas at temperatures from ambient temperature up to about 2000.degree. F.

Abstract: The invention relates to a method and apparatus for purifying the exhaust gases from plants for the production of cement clinker, in which in a multi-stage filter zone hot exhaust gases coming from a preheating zone are first of all cleaned of dust in a first filter stage and then in a further stage are purified of NH.sub.x compounds, heavy metals and trace pollutants, SO.sub.z and NO.sub.x. In order to achieve a particularly efficient and economic purification, the exhaust gases from the preheating zone are set before the first filter stage to such a filter zone inlet temperature that in this first filter stage at least a proportion of the easily volatile pollutant elements and pollutant compounds are precipitated out of the exhaust gases in addition to the dust.

Abstract: Inhibitors of oxidation of sulfites to sulfates in sulfur dioxide scrubbing solutions are disclosed. The inhibitors are cationic polyelectrolytes which are water soluble, have a molecular weight of at least 10,000 daltons and contain quaternary amine groups. The polyelectrolytes are preferably present at 1-3000 ppm in alkali solutions with which a sulfur dioxide containing gas stream is contacted. The scrubbing solutions contain amines such as piperazinones, morpholinones, piperidines, piperazines, piperazinediones, hydantoins, triazinones, pyrimidinones, oxazolidones, N-carboxymethyl ethylenediamines, etc.

Abstract: A method and apparatus for reducing SO.sub.x and NO.sub.x levels in flue gases generated by the combustion of coal in a boiler in which low NO.sub.x burners and air staging ports are utilized to inhibit the amount of NO.sub.x initially produced in the combustion of the coal, a selected concentration of urea is introduced downstream of the combustion zone after the temperature has been reduced to the range of 1300.degree. F. to 2000.degree. F., and a sodium-based reagent is introduced into the flue gas stream after further reducing the temperature of the stream to the range of 200.degree. F. to 900.degree. F. Under certain conditions, calcium injection may be employed along with humidification of the flue gas stream for selective reduction of the pollutants.

Abstract: Low molecular weight hydrocarbons are removed from air by preheating the air and then passing the preheated air through a heated catalytic bed comprising a mixture of catalytic pellets and metal turnings. The turnings provide for uniform heating of the bed and enable the desired temperatures of the catalytic bed to be maintained with minimum expenditure of energy.

Abstract: This invention is a catalytic element for use in the catalytic oxidation of ammonia. The element comprises a foraminous structure fabricated from a material consisting essentially of a metal selected from the group consisting of platinum, rhodium, palladium and alloys of mixtures thereof characterized by (a) a novel configuration whereby the initial product of the formula: curve the flat ratio (C/F) multiplied by mesh count in inches (N) and wire diameter (d.sub.w), for said element is greater than at least about 0.08 and (b) where, for a given hydrogen throughput, the conversion efficiency is a function of the curve to flat ratio (C/F), wire diameter (d.sub.w) and mesh count (N) combination and conversion efficiency is improved by increasing the mesh count (N) for a given wire diameter, increasing the wire diameter (d.sub.w) for a given mesh count, and increasing the curve to flat ratio (C/F) to a ratio of above 1.0. Preferably the initial product of the formula is greater than 0.2, more preferably 0.

Abstract: A method for preparing smectite clay alkaline earth metal hydroxide and carbonate composite materials is described. The method uses low amounts of the clay added to water to which is added calcium oxide or calcium hydroxide. Optionally the calcium carbonate is formed in situ by exposure to air or to carbon dioxide in the solution. The product is dried to form the composite material which is used to remove SO.sub.x from flue gases.

Abstract: Porous particles of a calcium phosphate compound having a Ca/P ratio of 1.5 to 1.80, which contain open pores having an average pore size of 100 to 4000 .ANG. and are in the form of spherical particles having an average particle size of 1 to 40 .mu.m, and a process for their production. 90% of the total pore volume of the particles is occupied by pores having a pore size that is 0.5 to 2 times larger than the average pore size of the open pores and the total volume is at least 0.5 ml/g of the particles. The porous calcium phosphate particles are particularly useful as packings for liquid chromatography.

Abstract: A method of maintaining a given content of a substance A in an aqueous solution where it is continuously consumed and where the redox potential E, at least within the range of concentration used, approximately satisfies the equation:E=G+F(x)wherein x is the content of A, F is a function of x whose derivative dF/dx approaches zero when x assumes a high value, and G on the whole is independent of x but is influenced by other parameters, such as pH, temperature or the like. The addition of A is controlled in such manner that a set value of the redox potential is maintained. The set value is determined by increasing or decreasing the addition of A in a predetermined manner, whereupon the redox potential is measured, and the measured value is used for determining the set value.

Abstract: An exhaust gas purifying catalyst of this invention is a catalyst for mainly removing nitrogen oxides contained in exhaust gases, comprising: crystalline copper silicate expressed by the following composition formula;M.sub.n+m (Cu.sub.n Al.sub.m Si.sub.96-n-m O.sub.192).16H.sub.2 O, where M denotes one of sodium (Na) and potassium (K), and n+m<27. An exhaust gas purifying process of this invention employs the above-mentioned crystalline copper silicate catalyst. The exhaust gas purifying catalyst and the exhaust gas purifying process employing the same purify the nitrogen oxides (NOx) by facilitating the reaction between hydrocarbons (HC) and nitrogen oxides (NOx) contained in the exhaust gases more preferentially than the reaction between hydrocarbons (HC) and oxygen (O.sub.2) contained therein, thereby purifying the nitrogen oxides (NOx) and hydrocarbons (HC) at high efficiency.

Abstract: An exhaust gas cleaner comprising a catalyst carried on a heat-resistant ter, the catalyst comprising (a) one or more alkali metals, (b) one or more metals selected from the group consisting of Zn, Sn and transition metals excluding platinum-group metals, and (c) one or more rare earth metals, and a method of cleaning an exhaust gas with it. Alkali metals may be added to a fuel.

Abstract: Hydrogen sulfide is removed from a fluid stream containing hydrogen sulfide by contacting the fluid stream under suitable absorbing conditions with an absorbing composition comprising zinc titanate, alumina and silica promoted with a metal selected from the group consisting of phosphorus, tungsten, molybdenum, metals of Group VIII of the Periodic Table, and mixtures of any two or more thereof. An absorbing composition and a process for producing such absorbing composition are also disclosed.

Abstract: A method for reducing NO.sub.x emissions through the selective addition of hydrogen peroxide in the aqueous liquor of an absorber column, wherein periods of addition are determined by increases in temperature of the aqueous liquor.

Abstract: A coal combustion apparatus having prevented deterioration of a denitration catalyst due to volatile metal compounds contained in exhaust gases is provided, which apparatus comprises a combustion furnace, a denitration means for removing nitrogen oxides in an exhaust gas from the furnace by reducing nitrogen oxide with ammonia, a means for collecting ashes in the gas having left the denitration means and a means for recycling the collected ashes into the furnace, and is characterized in providing an oxygen concentration meter in the flow path of the gas between the furnace and the denitration means and also providing an oxygen concentration-controlling means relative to air fed inside the flow path of the gas from the furnace to the denitration means so as to control the oxygen concentration detected by the oxygen concentration meter to a definite value or higher.

Abstract: A catalyst system for the selective reduction of gaseous NO.sub.x in the presence of excess oxygen, having a copper-containing ZSM5 zeolite to which a NO.sub.x -containing gas is exposed, and means for introducing a metered volume of comminuted water-soluble, oxygen-containing organic compound (alcohol, aldehyde, ketone, ether) into the NO.sub.x -containing gas prior to exposure to the Cu-ZSM5 zeolite.Also, a method of treating automotive exhaust gas emissions, having an excess of oxygen, by the steps of: (a) introducing a water-soluble, oxygenated organic compound (steam/oxygenate mixture) into the exhaust gas emissions as a reductant and at a location closely adjacent the source of the exhaust gas generation (in an appropriate amount with respect to the NO.sub.x); (b) substantially immediately exposing the reductant/emission mixture to a transition metal-exchanged high silica ZSM5 zeolite (SiO.sub.2 /Al.sub.2 O.sub.3 of between 10-50) catalyst at a space velocity in the range of 20-80 K hr.sup.

Abstract: The invention describes a catalytic process for destroying NOx from oxygen-containing combustion products wherein methane serves as a reductant. The process comprises contacting the NOx-containing combustion products with a desired amount of methane and oxygen in the presence of a metal-exchanged crystalline zeolite having a silicon to aluminum ratio of greater than or equal to about 2.5 under conditions sufficient to effect conversion to gaseous nitrogen, water and carbon oxides. The zeolites are exchanged with a cation selection from the group consisting of cobalt, nickel, iron, chromium, rhodium and manganese.

Abstract: A process for the recovery of nickel catalyst metal from a top portion of a fluidized bed consists essentially of the steps of providing a sludge material including spent catalyst including recoverable catalyst metal in the form of particles which are finely divided, and an organic material consisting essentially of fat, the organic material being combustible or otherwise degradable under conditions attainable by fluidized bed techniques; feeding the sludge material into a base portion of a fluidized bed including a bed of inert carrier material; converting the organic material to waste gases in the fluidized bed; maintaining the fluidized bed under conditions which cause the particles of recoverable catalyst metal to rise to a top portion of the fluidized bed, the recoverable catalyst metal comprising particles having an average particle size of less than 50 microns; removing the particles of recoverable catalyst metal and the waste gases from the top portion of the fluidized bed; and separating the particle

Abstract: In a continuous process for the preparation of phosphorous acid with simultaneous production of hydrochloric acid, a reaction zone is provided which is in open communication with a first scrubbing zone. A portion of the reaction product is recycled from the bottom of the reaction zone into the top of the scrubbing zone and phosphorous acid is removed from the circulation. Hydrogen chloride gas escaping from the top of the first scrubbing zone is brought into contact, in a cooled, second scrubbing zone, with an overstoichiometric amount of water. Hydrochloric acid is obtained which is passed as starting material into the reaction zone or into the top of the first scrubbing zone. The external cooling of the second scrubbing zone is controlled such that the temperature in the reaction zone is kept constant at a desired value between 90.degree. and 130.degree. C. without adding any external cooling or heating energy. Pure hydrochloric acid is recovered in an absorption zone.

Abstract: A catalyst for the purification of a gas containing ozone or a component of offensive odor is composed of (A) a composite oxide comprising (a) titanium and (b) at least one element selected from the group consisting of Si, Zr, and P and (B) at least one element selected from the group consisting of Mn, Fe, Co, Ni, Ag, Pt, Pd, and Rh.