Abstract: A process for recovering copper from chalcopyrite is disclosed. The process includes oxidising sulphur in chalcopyrite with a solution under predetermined contact conditions and thereby releasing at least part of the copper in the chalcopyrite into the solution as copper ions. The process includes a subsequent step of reducing sulphur in a solid product from step (a) to a minus two, ie. sulphide, valence state with a solution under predetermined contact conditions. The process further includes a subsequent step of oxidising sulphur in a solid product from step (b) with a solution under predetermined contact conditions and thereby releasing at least part of the remaining copper in the solid product into the solution as copper ions. The process further includes recovering copper from one or more of the solutions from steps (a) and (c).

Abstract: Disclosed is a hitch-mounted lighting and safety accessory for a vehicle having a frame-mounted hitch sleeve. The hitch-mounted accessory includes tubing stock having a first and a second end, the first end being adapted for secure and reversible insertion into a hitch sleeve. When installed, the first end and an extension thereof sufficient to clear the rear of the vehicle, extend horizontally (relative to the ground) from the hitch sleeve. The tubing stock is then redirected a total of about 90 degrees at a location proximate the first end so that it extends upwardly in a substantially vertical plane. Accessories such as a safety beacon light or strobe, work lights, and an audible back-up alarm are mounted to the tubing stock. A wiring harness terminating in a male plug for insertion into a female plug mounted to the vehicle near the hitch sleeve is also provided.

Abstract: An aluminium smelting cell comprising side walls (5) and a floor (2) defining an active cathode, an anode (3) overlying the cathode floor (2), some said side walls (5) being covered by a wetted cathode material (6), such as one contained TiB.sub.2, so that the covered side walls become active cathode surfaces on which a film of aluminium metal forms to protect the side wall parts against bath attack, thereby enabling the cell to operate at the desired temperatures without the usual protective side ledge of the frozen electrolyte material.

Abstract: A method of operating an aluminum smelting cell during the start-up phase of the cell is described. The method includes forming a layer of boron oxide on the exposed surface of the cathode of the cell, forming a layer of aluminum on the boron oxide layer, and starting the cell. This melts the boron oxide layer to form a barrier impervious to oxygen at a temperature from about 400.degree. C. to about 650.degree. C., and the aluminum layer is melted to form a barrier to oxygen at temperature above about 600.degree. C. to about 1000.degree. C. to reduce the development of oxidation products.

Abstract: An aluminium smelting cell comprising a floor defining a cathode surface (4) which is substantially horizontal in the longitudinal direction of an overlying anode (1), shaped structures (2,3) projecting from the cathode surface (4) and having exposed surfaces of aluminium wetted material, the shaped structures being positioned to cause preferential contouring of the anode (1), particularly at its longitudinal edges (5,6) to allow for improved bubble release and to minimize cell resistivity.

Abstract: A calcined microsphere of ultrafine bauxite particles having a mean particle size in the range 0.01 to 0.3 micrometers, said microsphere having a particle size less than 30 micrometers and being characterized by a substantially solid form having a pycnometric density substantially falling in the range 3.2-3.0 g/cm.sup.3, a BET surface area substantially falling in the range 0.05 to 0.5 m.sup.2 /g and a crystal grain size less than 4 micrometers, the surface chemistry of the microsphere being modified to enhance the wettability of the microsphere and to improve its ability to bond strongly with matrix materials in use.

Abstract: A calcined microsphere of ultrafine bauxite particles having a mean particle size in the range 0.01 to 0.3 micrometers, said microsphere having a particle size less than 30 micrometers and being characterized by a substantially solid form having a pycnometric density substantially falling in the range 3.2-3.9 g/cm.sup.3, a BET surface area substantially falling in the range 0.05 to 0.5 m.sup.2 /g and a crystal grain size less than 4 micrometers, the surface chemistry of the microsphere being modified to enhance the wettability of the microsphere and to improve its ability to bond strongly with matrix materials in use.

Abstract: A low cement castable refractory comprising 85 to 96% by weight of a calcined ultrafine bauxite aggregate characterized by a particle size of less than 10 um, 2 to 10% by weight of a suitable cement material, 0 to 8% of weight of a thixotropic agent and 0 to 2% by weight of suitable deflocculants and plasticizers, the cement material comprising calcium aluminate cement having an alumina content of 40 to 85% and the thixotropic agents being selected from those containing microfine silica, and/or reactive alumina, the inorganic deflocculants and plasticizers being selected from alkali phosphates, lignosulphonates or naphthalene sulphonates. A method of making a low cement castable refractory and installing a low cement castable refractory are also described.

Abstract: An aluminum smelting cell comprising a cathode having an active upper surface, a plurality of anodes each having a lower surface spaced from the upper surface of the cathode, said cathode upper surface being sloped at an acute angle in a primary or longitudinal direction of each anode, and being formed with pairs of oppositely sloped surfaces extending in a transverse or secondary direction under each anode to cause complementary shaping of the lower anode surfaces to reduce the migration of bubbles between the anode and cathode along the anode surfaces in said primary or longitudinal direction to thereby reduce the path length of said bubbles whereby the turbulence caused by coalesced bubble disengagement from the bath electrolyte is significantly reduced while maintaining adequate bath circulation between the anode and cathode.

Abstract: A process for the hydrometallurgical recovery of metal value, particularly copper, from copper-containing sulphide materials in which the material is conventionally ground and reacted with a solution containing less than 3 moles per liter of chloride ion, and optionally as little as 15 g/liter, together with sulphate ions with continuous oxygen injection and vigerous agitation. The reacting may be carried out at a pH in the range of 0.5-4, at moderate pressure as low as atmospheric pressure and at a moderate temperature below the boiling point of the solution such as 85.degree. C.

Abstract: A filter medium suitable for hot liquid and gaseous materials, more particularly molten metals, for example aluminium and its alloys, is characterized by the use of sintered ultrafine bauxite granules. Filter media according to the invention exhibit superior thermal shock resistance, may be used repeatedly and are much cheaper than filter media of the prior art.