Abstract: A heat exchanger including a plurality of tubes arranged in at least three side-by-side planes, the tubes being held at their ends in the sidewalls of an even-sided polygon of at least six sidewalls, each sidewall being connected to its opposite sidewall by tubes in at least one of the planes.

Abstract: In a process for producing aluminum by electrolysis of alumina dissolved in a cryolite-based molten salt contained between a cathode and a plurality of previously baked carbon anodes which are consumed with evolution of oxides of carbon, the improvement including setting all anodes at the same time.

Abstract: (1) Rehydration bondable alumina of median particle size less than 5 microns, LOI (250.degree. to 1100.degree. C.) about 4 to 12% by weight, and having the ability to yield rehydration bonded objects of lower density and higher strength as compared with objects made of seven micron rehydration bondable alumina, or density less than 0.9 cm.sup.3 /g at strength about equal to or greater than 7 MPa; (2) rehydration bondable alumina having the ability to yield rehydration bonded objects having at least 0.6 cc of pore volume per gram for pores smaller than 300 Angstroms. Also encompassed are materials containing such alumina and originating from e.g. bauxite.

Abstract: Metal particles, e.g. aluminum, are treated with ionic organic phosphate, being thereby transformed to a state capable of resisting attack from an aqueous medium. The treated particles may be incorporated into a water-borne coating.

Abstract: A method of determining the penetration of an isotherm into a mass, including the steps of distributing material in the mass, the material having the ability to fix a record of an isotherm, cycling the temperature of the mass, and checking the material for the location of the isotherm relative to the mass.

Abstract: A system for the precipitation of Al(OH).sub.3 from green liquor is provided which comprises process and apparatus for feeding the green liquor into the bottom of a chamber containing a supersaturated solution of alumina and Al(OH).sub.3 seed particles. The flow of green liquor into the bottom of the chamber is maintained at a rate sufficient to suspend the seed particles in the chamber with minimum turbulence so that the liquor is in approximately plug flow. As Al(OH).sub.3 precipitates on the seed particles, the particles grow larger and gradually move to the bottom of the chamber where they are removed. The solution, somewhat depleted with respect to Al.sub.2 O.sub.3, overflows the chamber to return to the process.

Abstract: In a composition of matter including a leafing, metallic pigment and a means for inhibiting reaction of the pigment to form hydrogen gas, the improvement including a liquid fatty acid in an amount effective for at least reducing loss of optical properties which would occur in the absence of such fatty acid.A water-borne coating containing an effective amount of liquid fatty acid for improved optical properties.

Abstract: Method for improving yield of solid, sodium-poor fluoride material from an aqueous solution having ionic species containing sodium, aluminum and fluorine, including neutralizing the solution incompletely to precipitate aluminum fluoride hydroxide hydrate in preference to sodium-containing compounds such as chiolite or cryolite.

Abstract: A manufacture, including a ceramic tube, and a metal liner within the tube and closer to one end of the tube than the other. A method of using such a manufacture wherein material such as subliming material is fed through the tube in the direction from the liner-close end to the liner-distant end.

Abstract: A causticization method including the steps of calcining limestone in the presence of additive means for producing lime of increased lime efficiency relative to the lime that would result from calcining such limestone without the presence of the additive means, lime efficiency being determined on a sodium carbonate solution for which conditions, other than the character of the lime, are fixed, and subsequently feeding the lime of increased lime efficiency into the sodium carbonate solution for producing sodium hydroxide and calcium carbonate from the sodium carbonate.

Abstract: In the electrolytic production of aluminum, in a cell having a side wall including a layer of carbon electrically insulated from a jacket of metal, the improvement including interposing a layer of tile (27) between the carbon layer (23,24) and the metal jacket (28).

Abstract: An electrolysis method involving electrolyzing, between anodic and cathodic surface areas, a compound dissolved in a solvent. A liquid cathodic body is located in a region such that it is possible for waves in the body to touch anodic surface area. The improvement includes placing a bed of objects into the mentioned region. Interstices remain between the objects for accommodating liquid from the mentioned body.

Abstract: A method is disclosed for preventing the condensation of aluminum chloride (AlCl.sub.3) in a fractional distillation column which is operated to separate a fraction which does not include AlCl.sub.3 from a mixture containing AlCl.sub.3 and other metal chlorides and which is operated at temperatures which include the sublimation or melting points of AlCl.sub.3 at the operating pressure of the column. According to this method, titanium tetrachloride (TiCl.sub.4) is maintained in the column in an amount at least as great, by weight, as the amount of AlCl.sub.3 contained in the mixture.

Abstract: Metal chlorides such as aluminum chloride (AlCl.sub.3) are separated from a mixture containing metal chlorides including AlCl.sub.3 and ferric chloride (FeCl.sub.3). In order to effect this separation, the mixture is subjected to a fractional distillation process utilizing an array of distillation columns. According to this process, the mixture is introduced into a first distillation column which is operated at temperatures and pressures sufficient to separate FeCl.sub.3 from the mixture while avoiding the formation of a solid solution of FeCl.sub.3 and AlCl.sub.3 within the column. At least one additional distillation column is then employed to separate metal chlorides from the remaining mixture from the first column.

Abstract: A method for the electrolytic production of metal, including electrolyzing, between anodic and cathodic surface areas, a compound of the metal dissolved in a molten solvent, the electrolyzing being performed at a temperature such that the metal is formed in the molten state, the metal collecting in a molten metal pad, wherein the improvement includes the provision of cathodic surface area in the form of an array of elements like islands protruding out of the pad into the solvent toward the anodic surface area for establishing a series of locations at which the anode-cathode distance is up to 11/4 inches.

Abstract: The invention involves a cell which may be used for producing molten aluminum by electrolysis of aluminum oxide in a molten bath. The cell includes a cathode and an anode, a bar and a hanger. The bar is connected at an upper end to the hanger and at a lower end to the anode. Flexible means is provided for supplying electrical current through the bar to the anode. A jack means raises and lowers the hanger and thus the anode. Included in the invention, the hanger is mounted at at least two separated points, one higher than the other, in encompassing, sliding relationship, on a single, upright, circular cross-sectioned post passing through the hanger. By this technique, the hanger is constrained to move up and down, without relation about horizontal axes.

Abstract: A method of forming the chloride of a metal-oxygen-containing substance, including the steps of coating particles of such substance with green carbon, i.e. carbon which contains substances more volatile than carbon, heating the coated particles to drive off the volatile matter and produce openings such as pores and fissures, and then reacting the particles from the step of heating with a source of chlorine.

Abstract: Aluminous material is chlorinated in the presence of a reducing agent at pressures greater than three atmospheres. A greater than linear increase in reaction rate obtained at superatmospheric pressures is a feature of the chlorination reaction which is employed to increase aluminum chloride production rate. Choice of pressure used is governed more by mechanical limitations than by an upper limit inherent to the chemical reaction.

Abstract: A method for the electrolytic production of metal, including electrolyzing, between anodic and cathodic surface areas, a compound of the metal dissolved in a molten solvent, the electrolyzing being performed at a temperature such that the metal is formed in the molten state, the metal collecting in a molten metal pad, wherein the improvement includes the provision of cathodic surface area in the form of an array of elements protruding out of the pad into the solvent toward the anodic surface area for establishing a series of locations at which the anode-cathode distance is up to 11/4 inches.

Abstract: Unique polished metal flake pigmented, plastic powder products produced, e.g. by a process including the measure of brush polishing metal flake particles and plastic particles together.