Abstract: A method for removing mercury from a sulfuric acid solution including the steps of mixing the sulfuric acid solution with a hydrocarbon solution to form a chemical complex containing mercury. The hydrocarbon solution typically contains a lower alcohol and a halogen component. The mercury complex is removed by the addition of activated carbon and subsequent filtration. Alternatively, solvent extraction, volatilization or other suitable separation techniques can be used.

Abstract: Antimony values are separated from a material containing a sulfo-antimony compound of copper, e.g. tetrahedrite ore concentrate, by a process involving establishing a pool of molten lead, adding a metallic alkali metal, e.g. metallic sodium, to the molten lead in an amount which is sufficient to reduce the combined antimony of the sulfo-antimony compound or compounds of copper of the tetrahedrite to metallic antimony, adding the tetrahedrite ore concentrate to the molten lead, and mixing together the alkali metal, molten lead, and tetrahedrite ore concentrate. The alkali metal and sulfo-antimony compound of copper are reacted together in the presence of the molten lead for a period which is sufficient to reduce the antimony of the sulfo-antimony compound of copper to metallic antimony and to form one or more sulfo-alkali metal compounds of copper, and a matte phase which separates from the molten lead.

Abstract: Lead is separated from material containing lead sulfide, e.g. galena ore concentrate, by a substantially autogenous process involving establishing a pool of molten lead in a kettle, adding a metallic alkali metal, e.g. metallic sodium, to the molten lead in an amount sufficient to reduce the combined lead of the lead sulfide to metallic lead, adding the ore concentrate to the molten lead pool, and mixing together the metallic sodium, molten lead and ore concentrate. The sodium reacts rapidly and exothermically with the lead sulfide to reduce the combined lead of the lead sulfide to metallic lead and form sodium sulfide. The thus-liberated metallic lead reports in the molten lead pool, and a matte phase containing the sodium sulfide separates from the molten lead and forms on the surface of the molten lead pool.

Abstract: Casting side dam apparatus for use in a twin-belt continuous casting machine. The side dams each comprise a multiplicity of slotted dam blocks strung on a flexible metal band. The dam blocks are each formed of a beryllium-copper alloy and are resistant to intergranular cracking and chipping over a prolonged discontinuous, cumulative period of thermal cycling between temperatures ranging between about 800.degree. F. and about 300.degree. F.

Abstract: Photoconductive zinc oxide characterized by having improved electrophotographic properties and particularly increased discharge speed, and produced by a process involving mixing the photoconductive zinc oxide powder to be improved with 0.01% by weight or more tellurium calculated as Te, and contacting the thus-obtained mixture with a free oxygen-containing gas while heating the mixture at elevated temperature sufficiently high and for a time sufficient to result in the zinc oxide having the improved electrophotographic properties. The heating temperature and/or heating time is held below that temperature or time at which sintering of the thus-treated product occurs.

Abstract: Casting side dam apparatus for use in a twin-belt continuous casting machine. The side dams each comprise a multiplicity of slotted dam blocks strung on a flexible metal band. The dam blocks are each formed of a beryllium-nickel-copper alloy and are resistant to intergranular cracking over a prolonged period of exposure to elevated temperatures ranging from about 300.degree. F. to about 800.degree. F.

Abstract: Bismuth is recovered as elemental bismuth or as a Pb-Bi alloy from an air-pervious residue cake of de-bismuthizing dross of concentrated alkaline bismuthide content, by heating the cake in air to the ignition temperature of the cake to ignite the cake, and burning autogenously in a flameless or substantially flameless combustion the thus-ignited cake to oxidize the alkali and a portion of the lead to the exclusion of the bismuth. A powder-like residue, formed by the burning, comprises bismuth, lead, lead oxide and alkali oxide. The lead oxide and alkali oxide of the residue are then selectively dissolved in an oxide-dissolving flux, e.g. molten lead chloride, and the flux containing the lead oxide and alkali oxide is skimmed from the resulting lead bismuthide alloy. The lead of the alloy can, if desired, be separated to recover elemental bismuth, for example, by reacting the Pb-Bi alloy in molten droplet or molten particulate form with Cl.sub.2 to form PbCl.sub.

Abstract: Alkaline bismuthide is concentrated in a debismuthizing dross comprising the alkaline bismuthide and molten lead by a method involving charging the dross onto a heat-resistant screen or sieve of suitable mechanical strength. The screen has openings of such size as to enable the formation and retention thereon of a molten lead-pervious residue cake comprising particles of the alkaline bismuthide, for example of crystals of calcium magnesium bismuthide (Ca Mg.sub.2 Bi.sub.2). The dross is subjected on the screen to the influence of a partial vacuum drawn from the opposite side of the screen from the dross, and the molten lead is sucked or pulled through pore channels of the porous residue cake of the alkaline bismuthide particles which is formed on the screen, and without any significant physical compression of the cake with attendant blockage of the pores of the cake, and then through the screen openings under the influence of the partial vacuum.

Abstract: Copper sulfide in the presence or absence of metallic copper contained in a dross obtained from the copper drossing of lead bullion is separated from metallic lead entrained or occluded in the dross by introducing the dross into a vessel other than a reverberatory furnace, usually a kettle, also introducing an alkali metal sulfide, preferably sodium sulfide, into the kettle, and heating the dross and alkali metal sulfide together in the kettle at an elevated temperature not in excess of 1200.degree. F. and for a time sufficient to melt together the dross and alkali metal sulfide. The thus-obtained molten dross releases the entrained molten lead which falls to the bottom of the kettle.

Abstract: Decrepitation of the catalyst occurring in the initial upstream portion of the catalyst bed of the reaction zone in a process for catalytically reducing sulfur dioxide to obtain elemental sulfur is avoided or minimized by employing as the catalyst in at least the initial upstream portion of the bed a supported sulfate of an iron group metal.

Abstract: Ammonia is added to combined aqueous scrubbing solutions containing an organic base-sulfuric acid reaction product, preferably an aromatic amine-sulfuric acid reaction product, an organic base-sulfurous acid reaction product, preferably an aromatic amine-sulfurous acid reaction product, and water in one or more separating zones located exteriorly of an absorption tower. The combined aqueous scrubbing solutions are obtained from sulfurous acid and sulfuric acid solution scrubbing sections of the absorption tower wherein an organic base, preferably an aromatic amine, is utilized as absorbent in a lower absorber section of the tower to remove SO.sub.2 from a SO.sub.2 -containing gas mixture, followed by scrubbing the SO.sub.

Abstract: SO.sub.2 is removed from a SO.sub.2 -containing gas mixture utilizing an aromatic amine as absorbent, followed by scrubbing the SO.sub.2 -depleted, aromatic amine-enriched effluent gas with sulfurous acid-and ammonium sulfate-containing aqueous solution to remove substantially all of the gaseous aromatic amine from the gas. The effluent gas is discharged ultimately to the atmosphere without any additional scrubbing of the gas, after its discharge from the sulfurous acid scrubbing zone, with sulfuric acid solution or any other acid solution or any acid.

Abstract: Tetrahedrite ore concentrate, sodium sulfide added as such or formed in situ, calcium values preferably supplied as lime, and a reducing agent, e.g. coke, are smelted for a period sufficient to convert a major portion or substantially all of the antimony to a water-soluble sodium compound of antimony and sulfur and a major portion or substantially all of the arsenic also contained in the concentrate to a water-insoluble calcium compound of arsenic and oxygen. The sodium sulfide is incorporated into the charge for the smelting in an amount sufficient to convert at least a major portion of the antimony into the water-soluble sodium compound of antimony and sulfur; and the lime is incorporated into the smelting charge in amount sufficient to convert at least a major portion of the arsenic into the water-insoluble calcium compound of arsenic and oxygen.

Abstract: SO.sub.2 is removed from a SO.sub.2 - containing gas mixture utilizing an aromatic amine as absorbent, followed by scrubbing the SO.sub.2 - depleted, aromatic amine - enriched gas with sulfurous acid solution to remove most of the gaseous aromatic amine therefrom and then with dilute sulfuric acid solution to remove substantially all of the small amount of residual gaseous aromatic amine from the gas. The aqueous scrubbing solutions containing aromatic amine sulfite and aromatic amine sulfate from the respective sulfurous acid and sulfuric acid scrubbing zones are combined and ammonia is added thereto, resulting in release of the aromatic amine and in the formation of ammonium sulfate. Aqueous solution containing the ammonium sulfate is introduced into the upper portion of the sulfurous acid scrubbing section.

Abstract: Zinc dust composed of generally spherical zinc dust grains and having a grain size distribution such that at least about 98% of the grains have a grain size less than 15 microns and no more than about 3% of the grains have a grain size less than 2 microns, and especially well adapted for use in corrosion-inhibiting coating compositions where thin but effective protective coatings are desired or required. The zinc dust has a metallic zinc content of about 96%-98%. The corrosion-inhibiting coating compositions, and apparatus and method for the preparation of such zinc dust are also disclosed.