National Research Development Corporation

Mineral Industry Research Organisation

The British Petroleum Company, P.l.c.

Metallurg, Inc.

Chinuka Limited

Derek J Fray

Ramachandran Vasant Kumar

James Henry Cleland

Robert Gee

Bernard K Thomas

John P Chilton

Arthur V Cooke

Herbert A Hancock

David R Morris

Piers M Copham

James A Charles

Alan J Godsell

A method for the detection and measurement of a minor element in a molten metal, the minor element being selected from the group of phosphorous, silicon, arsenic, antimony and sulfur, includes providing a first electrical lead (5) and immersing it in the molten metal (6), disposing a solid electrolyte matrix (2) in the molten metal in spaced relationship to the first electrical lead, providing a second electrical lead (3) connected to the solid electrolyte matrix (2) so that the matrix is between and separates the leads when the matrix is disposed in the molten metal, and connecting a voltmeter (7) between the other ends of the electrical leads and measuring the EMF between the leads as an indication of the concentration of the minor element in the molten metal. The solid electrolyte is a matrix (2) of alumina selected from the group consisting of .beta.-alumina and .alpha.+.beta. alumina and includes a compound of the element to be detected and measured, oxygen, and an element from the group consisting of alkali and alkaline earth metal elements. The elements are chemically combined with the oxygen and the compound dissociates into its constitute elements under the conditions of measurement in the molten metal. The solid electrolyte matrix may be in the form of a closed end of a tubular member (1).

Method for measuring a minor element in a molten metal

The concentration of an element in a molten metallurgical phase (3) is measured by applying an electrical potential across two electrodes (1, 2) separated by a solid electrolyte (7) containing cations of the element to be measured immersed in the melt, and measuring the current flowing between them. The solid electrolyte is preferably of .beta.-alumina or zirconium silicate or phosphate.

Monitoring of pyrometallurgical processes

The invention provides a method of transporting a liquid A past or around a barrier, by adding a solute S to liquid A on one side of the barrier and correspondingly removing solute S from liquid A on the other side of the barrier, the solute S being such as to change the density of the liquid A when dissolving in it, thereby providing a motive force for its motion around the barrier. An example of the application of the invention is in a two-part electrolytic cell (1) comprising electrowinning and electrofining half cells (2 and 3, respectively), wherein the metal, solute S, is electrowon into a liquid (16,16a), liquid A, on one side of the cell's common electrode (4), the barrier, in the electrowinning half cell (2), and electrolytically removed from the liquid (17,17a) on the other side of the common electrode (4), in the electrorefining half cell (3).

Transporting a liquid past a barrier

A carbon block acts as a cell electrode. Channels are formed in its face which is to face the cell diaphragm. The channels provide an interconnected network including retention pools arranged to hold, release, break up and mix a liquid stream passing through them.

Electrode for electrorefining

An electrochemical sensor for hydrogen has, as its reference, a metal having a choice of oxidation states, the metal redox reaction comprising the reference. The sensor preferably comprises

Electrochemical sensor for hydrogen sensing

Metal separation process

Powdered FeMn alloy is leached with liquid bismuth, which alloys preferentially with the manganese to form liquid BiMn alloy, leaving behind iron powder. The BiMn is then electrorefined; an anode 1 selectively ionises the manganese, which is carried to the cathode 3 where it is reduced to the metal and collected in a stream of molten aluminium as AlMn master alloy.

Separating a ferro alloy

Zinc and other metals are recovered form strongly bound zinc ferrite compounds in furnace dust. To the dust is added 1 weight percent of free zinc oxide unless already present. The dust is treated for 1 hour at 750C with a 20:1 air:chlorine mixture whereby the zinc, lead and cadmium are removed from the dust as volatilised chloride.

Zinc recovery from furnace dust

This method of obtaining an aqueous solution of metal values from an insoluble metal oxide is possible where the metal has a lower oxidation number in the solution than in the insoluble oxide, for example manganese (+2 and +4 respectively). The oxide, such as MnO.sub.2, is treated with hot mineral acid such as HCl in the presence of coal. After some hours, the liquid comes to contain most of the manganese as dissolved Mn(II) ion.

Obtaining aqueous solution from insoluble metal oxide

A method of cation reduction by anode-assisted electrolysis comprises electrolyzing cations at a cathode of a cell in which the anolyte contains ferrous ion as a reducing agent, with relative motion between the anode and the anolyte such as to promote contact of the anode with ferrous ion despite their mutual electrostatic repulsion, wherein the concentration of the ferrous ion is from 0.5 to 10 g/l. The relative motion between the anode and the anolyte can take the form of air-sparging. The method can be used to produce copper metal from copper solution. While static relationship is maintained between the cathode and the catholyte, the anolyte being in free communication with the catholyte.

Anode-assisted cation reduction

Electrolysing an aqueous solution of zinc chloride or cadmium chloride of a concentration of 15-35 weight % at pH 2-3.5 below 35 C with gas agitation at a current density exceeding 1000 A/m.sup.2, whereby coherent zinc or cadmium is yielded at the cathode.

Zinc chloride electrolysis

Apparatus for determining the lithium content of a substance by monitoring the e.m.f. generated between the substance and a reference material containing lithium, the substance and reference being separated from one another by a solid electrolyte which is electrically conductive to lithium ions, comprises a probe adapted to contain the reference material and to separate the reference material from the substance when the probe is introduced thereto, and in which the solid electrolyte of the probe comprises .beta.-spodumene; a preferred tubular probe form of said apparatus being produced by a process in which a pellet of .beta.-spodumene is fabricated in situ in the end of a tube of refractory material. In addition, a process for the determination of lithium present in a substance comprises determining the e.m.f. generated between the substance and a reference material containing lithium, in which the reference material and substance are separated by a solid electrolyte comprising .beta.-spodumene.

Determination of lithium, sensor therefor and method of making said

A method for the detection or determination of an element in a substance comprising that element by monitoring the e.m.f. generated between the substance and a reference material, in which the reference material is a solid electrolyte comprising a .beta.-alumina containing said element or a solid compound of said element separated from the substance by said electrolyte.

Method for detecting elements

Polycrystalline gallium beta-alumina is made by electrolyzing sodium beta-alumina using, as the anode, liquid gallium and liquid gallium chloride in contact with the beta-alumina.

Method of making metal beta-alumina and refining metal using it

A molten metal, such as aluminium, is refined by passing a stream thereof into an anode comprising a bed of conductive particles, such as carbon, in a molten or conductive-solution salt. A diaphragm, pervious to the salt but impervious to the molten metal, separates the anode from a cathode comprising a bed of conductive particles in a salt which is molten or in conductive solution.

Growing community of inventors

Cambridge, United Kingdom

Derek J Fray