Abstract: A process for wet-treating an exhaust gas to remove oxides of sulfur and of nitrogen including:1. washing the exhaust gas with a slurry containing one or more magnesium compounds to remove oxides of sulfur from the exhaust gas;2. washing the exhaust gas treated in step (1) with an aqueous solution of an alkali metal iodide and/or an alkaline earth metal iodide to remove the oxide of nitrogen; and3. contacting the slurry from step (1) with the aqueous solution from step (2) to regenerate the solution of alkali metal iodide and/or alkaline earth metal iodide and to decompose any nitrite formed in step (2) to nitrogen.

Abstract: Nitrogen oxides and sulfur oxides are removed from exhaust gases in a two step process including a slurry removal of the sulfur oxides followed by washing the gases with an aqueous solution of an alkali metal iodide and/or an alkaline earth metal iodide.

Abstract: A process for producing styrene which comprises subjecting 4-vinylcyclohexene to gas phase catalytic oxidation with a molecular oxygen-containing gas, for example, air, characterized in that the oxidation is carried out by use of a catalyst composition represented by the general formula,Mo.sub.12 Bi.sub.0.1.sub.-10 Fe.sub.0.sub.-15 Co.sub.0.sub.-15 Pb.sub.0.sub.-15 X.sub.0.sub.-10 Y.sub.0.sub.-3 O.sub.nwherein X is at least one element selected from the group consisting of zirconium, cadmium, niobium, and antimony; Y is at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, cesium and thallium; 1.ltoreq.Fe + Co + Pb.ltoreq.25; and n is the number of oxygen atoms sufficient to replenish the valences of other elements. According to the above-mentioned process, styrene can be produced in a high yield.

Abstract: Unreacted free ammonia and ammonium carbamate are removed from a urea synthesis solution efficiently by first heating the solution up to 205.degree.-250.degree. C and then, in a second, separate step, stripping the heated solution with a stripping gas but under adiabatic conditions to remove the unreacted materials. The process is applied as an integral part of a continuous urea preparation.

Abstract: Sulfur oxides and/or nitrogen oxides are removed from waste gas containing the same by adding chlorine dioxide or ozone gas to the waste gas in case where nitrogen monoxide is contained in the waste gas, and by scrubbing the waste gas with an aqueous scrubbing solution containing the sulfite of alkali metals or ammonium and oxidation retardant consisting of the sulfide, polysulfide or thiosulfate, of alkali metals or ammonium and thiourea.

Abstract: A method is provided for removing ammonia from the sour water stream of a coal gasification process. The basic steps comprise stripping the ammonia from the sour water; heating the stripped ammonia to a temperature from between 400.degree. to 1,000.degree. F; passing the gaseous ammonia through a reactor containing a sulfided catalyst to produce elemental hydrogen and nitrogen; and scrubbing the reaction product to obtain an ammonia-free gas. The residual equilibrium ammonia produced by the reactor is recycled into the stripper. The ammonia-free gas may be advantageously treated in a Claus process to recover elemental sulfur. Iron sulfide or cobalt molybdenum sulfide catalysts are used.

Abstract: Nitrogen oxides can be efficiently removed from waste gas containing the same by oxidizing nitrogen monoxide into nitrogen dioxide, and then by scrubbing said waste gas with an aqueous scrubbing solution containing (a) a sulfur-containing reducing compound of alkali metals or ammonium such as alkali or ammonium sulfites, thiosulfates, sulfides, polysulfides and hydrosulfites and (b) a catalytic compound such as amino compounds, nitro compounds and oxidation or reduction derivatives thereof.

Abstract: A process is described for producing high purity phosphoric acid from phosphate rock including low grade phosphate rock material such as Idaho phosphate ores having P.sub.2 O.sub.5 contents as low as 20 percent. Finely divided phosphate rock, sulfuric acid, phosphoric acid and water are charged to a mixing zone in proportions such that the pH of the resultant slurry is in the range 0.8 to 1.2 and the calcium ion content of the liquid phase of the slurry is in the range 3 to 4 percent by weight. Sulfuric acid is charged to the mixing zone in a quantity sufficient to convert the nonphosphate calcium compounds in the rock to calcium sulfate plus the quantity required to convert the contained calcium phosphate to monocalcium phosphate, phosphoric acidis charged to the mixing zone in quantities such that it is, on a molar basis, from about 1.2 to about 1.4 times the P.sub.2 O.sub.

Abstract: A method for reducing sulfur dioxide wherein ammonia is used as the reducing agent. The reduction may be accomplished either thermally or catalytically and the principal products obtained will be elemental sulfur and/or hydrogen sulfide, depending principally upon the particular conditions and relative reactant concentrations actually employed. The sulfur dioxide may be derived from essentially any source. In a preferred embodiment, however, the sulfur dioxide will be derived from a flue gas stream and the same will be separated therefrom with an absorption process wherein ammonia (on an aqueous ammoniacal solution) is also used as the absorbent.

Abstract: Novel water soluble, inorganic complexes are obtained by reacting, in the presence of aqueous ammonia, at least one non-alkaline metal selected from Groups I-VIII of the Periodic Table with an alkali metal hydroxide. An excess of the non-alkaline metal or metals is introduced into a reaction vessel, preferably already containing the aqueous ammonia, and the alkali metal hydroxide is thereafter incrementally added in such manner as to create localized areas of high concentration and pH approaching a value of 14. The hydrooxide in these areas of high concentration, in combination with reactive NH.sub.2 groups provided by the aqueous ammonia, causes erosion of the non-alkaline metal, the formation of non-alkaline metal ions and the production of a monomeric, metal amide complex.

Abstract: A process for purifying waste gypsum from the wet phosphoric acid process to a maximum fluorine content of 0.25 % by weight based on the anhydride, which comprises adding active silicic acid in two portions during the course of the phosphoric acid process, wherein at least half the total amount of silicic acid added is added during the decomposition of the crude phosphate and the remainder is added after the end of the decomposition but before the waste gypsum is filtered off, and the waste gypsum, after it has been filtered, is made into a suspension with water, separated from the liquid phase and dried.

Abstract: A process is provided for the defluorination of wet process phosphoric acid whereby hydrogen ion is removed, and the concentration of P.sub.2 O.sub.5 is adjusted with water, the calcium concentration, calculated as CaO, is adjusted by adding a source of calcium phosphate at temperatures of about 25.degree. C. to 75.degree. C. while maintaining a pH of about 2 or below to achieve substantially the maximum calcium content in aqueous solution and raising the temperature of the solution to about the boiling point to initiate the hydrolysis of silicofluoride and precipitate calcium fluoride which is separated, thereby producing a solution with an enhanced phosphoric acid content.

Abstract: A process for removing nitrogen oxide contained in a waste gas is disclosed which includes oxidizing the nitrogen oxide to nitrogen dioxide by mixing the gas with nitric acid vapor in the presence of porous adsorbing agent such as silica gel, colloid earth, alumina, molecular sieves or the like and removing the nitrogen dioxide by absorption with an alkali aqueous solution.

Abstract: Copper, zinc and nickel are recovered from sulfide concentrates prepared from ores of one or more such metals by subjecting such concentrate to a leaching operation which comprises slurrying the concentrate in an aqueous solution containing ammonium sulfate and free ammonia and vigorously agitating the slurry at 50 to 80.degree. C. and below 10 psig. in the presence of free oxygen while vigorously recirculating said oxygen from above the surface of the slurry to a substantial depth below such surface. The resulting pregnant leach solution contains copper, zinc, and/or nickel in dissolved form complexed with ammonia and such solution is treated to recover the dissolved metal. The undissolved sulfidic residue from the leaching operation is subjected to a secondary flotation operation to produce a sulfide concentrate containing the metal values not dissolved in the leaching operation, and such concentrate is treated to recover such values, as by smelting or by releaching.

Abstract: A process for the purification of phosphoric acid containing cationic impurities is disclosed wherein there is added to a crude phosphoric acid an organic solvent miscible in all proportions with water and phosphoric acid and thereafter contacting the resulting solution with an inorganic material in aqueous or solid form to effect the preferential passage of the impurities of the crude phosphoric acid/organic solvent solution into an aqueous inorganic phase with phosphoric acid remaining in the organic solvent phase from which purified phosphoric acid is recovered by distillation of the organic solvent.

Abstract: A process for the production of phosphorus from low-grade phosphate rock containing at least 5% by weight of each of iron and aluminum (calculated as their oxides) by heating a mixture of the rock, calcium oxide and a carbonaceous reductant in a reaction chamber at a temperature of at least 1400.degree. C to produce molten reaction products containing ferrophosphorus and a calcium aluminate slag which is liquid at the reaction temperature, and gaseous reaction products containing elemental phosphorus. The gaseous reaction products are withdrawn from the reaction chamber and elemental phosphorus is recovered therefrom. The ferrophosphorus is separated from the liquid calcium aluminate slag and subjected to an oxidizing treatment in the presence of a calcium-containing material to produce metallic iron and calcium phosphate. Calcium phosphate this produced is recycled to the reaction chamber.

Abstract: The effluent streams from utility stack gases containing nitric oxides and sulfur dioxide are sequentially oxidized, absorbed with effluent spent alkylation acid, the unabsorbed remaining gases contacted with carbon monoxide from alkylation units in refinery cracking and other industrial plants to form sulfur, carbon dioxide and nitrogen, the carbon dioxide and nitrogen being vented, the sulfur oxidized to sulfur trioxide and contacting aqueous sulfuric acid therewith to effect concentration of said acid and suitability for recycle to an alkylation unit; the absorbate containing spent alkylation acid sequentially treated with a burning, oxidation, aqueous dilution and carbon monoxide treatment steps to form sulfuric acid for recycle to an alkylation unit and venting formed carbon dioxide and nitrogen.

Abstract: A method for manufacturing graphite whiskers which comprises: mixing one or more of gasified compounds having a condensed polycyclic structure of two to five benzene rings with a large amount of inert gas containing a small amount of CO, CO.sub.2 or H.sub.2 O; heating said gas mixture at 700.degree. to 1200.degree. C and a substantially atmospheric pressure to generate precursory carbon whiskers comprised of numerous carbon crystals orientated in a form of single sheet which is rolled up like a scroll or a plurality of separate sheets rolled in concentric relationships; and graphitizing said carbon whiskers at temperatures of 2700.degree. to 3000.degree. C in an atmosphere of inert gas.

Abstract: Urea is produced through an integrated, isobaric process in which raw ammonia synthesis gas, consisting essentially of H.sub.2, N.sub.2 and sufficient CO.sub.2 to produce the urea and compressed to a pressure slightly above the urea synthesis pressure, is decarbonated in a vertical film heat exchanger where it is contacted with a thin aqueous film containing NH.sub.3 with which the CO.sub.2 reacts to produce a concentrated carbamate solution that is withdrawn from the bottom of the exchanger and fed to a urea reactor. The compressed, unreacted synthesis gas containing traces of CO and saturated with NH.sub.3 is withdrawn from the upper part of the heat exchanger, NH.sub.3 is separated therefrom and recycled to the heat exchanger, and the balance of the unreacted synthesis gas is subjected to methanation to eliminate any CO and CO.sub.2 therein.

Abstract: A high pressure thermal hydrolysis process is described which comprises heating acid waste streams resulting from the manufacture of cyanuric acid and chlorinated derivatives of cyanuric acid, containing cyanuric acid and amino-substituted cyanurates, in a pressure vessel, at a temperature of from about 225.degree. to about 275.degree. C, to effect decomposition of these materials into ammonia and carbon dioxide. This process provides an effective pollution control means, compatible with existing commercial facilities.