Abstract: In accordance with the present invention, there is now provided a process for the production an anhydrous magnesium chloride-containing melt or electrolyte containing very low levels of MgO, typically less than 0.2% by weight MgO, directly from hydrated magnesium chloride feeds. More specifically, the process comprises the steps of a) feeding hydrated magnesium chloride in a furnace containing molten electrolyte from a magnesium electrolysis cell to produce a melt, the temperature in the furnace being maintained between 450.degree. and 65.degree. C.; b) simultaneously injecting an anhydrous hydrogen chloride-containing gas into the melt in an amount below the stoichiometric requirement of 2 moles of HCl per mole of magnesium chloride produced from hydrated magnesium chloride, and agitating the melt to keep any magnesium oxide in suspension in them melt, to dehydrate the magnesium chloride and react with the MgO in the melt so that the melt contains not more than 0.

Abstract: The present invention is concerned with a process for the direct smelting of zinc containing materials. The process includes volatilizing zinc from zinc-containing materials into a gas phase, while sulphur is fixed as iron sulphide in a Fe-S-O matte. Thereafter, zinc is recovered in metallic form with a suitable condenser apparatus from a zinc laden gas consisting of Zn(g), CO, CO.sub.2 and N.sub.2. Other metals like silver, cadmium, mercury and lead may also be recovered in this manner.

Abstract: A process for the production of pure magnesium chloride liquor from siliceous magnesium minerals comprises the steps of continuously leaching the siliceous magnesium mineral with a hydrochloric acid solution at a temperature higher than 50.degree. C. but below the boiling point and in such a manner as to maintain the pH of the slurry below 1.5 to prevent the formation of silica gel, continuously reacting such slurry with a reactive magnesia in order to raise the pH to 4.0-7.0 to precipitate substantially all the impurities from solution while preventing silica gel formation, and performing a solid/liquid separation of the slurry on suitable filtration equipment to obtain pure magnesium chloride liquor.

Abstract: A process for the preparation of anhydrous magnesium chloride containing acceptable amounts of MgO suitable for use in the electrolytic production of magnesium metal comprises the steps of feeding spray-dried magnesium chloride powder, or a magnesite or magnesia powder to a furnace containing a molten magnesium chloride melt at a temperature of about 750.degree.-850.degree. C., and reacting the melt with a carbonaceous reductant and chlorine. The gases are introduced using a gas disperser consisting of a rotating vaned impeller with a tube in the center of the impeller to create gas bubbles having a diameter smaller than 5 nm and having a gas hold-up as high as 30% of the original melt volume, and also ensure that the fine particles present in the melt are evenly suspended.

Abstract: A process for the production of Mg metal from impure Mg-containing materials is disclosed. The process comprises the steps of reacting a slurry of impure Mg-containing material with a hot HCl-containing gas stream to produce an impure MgCl.sub.2 slurry, purifying the MgCl.sub.2 slurry to form a substantially pure MgCl.sub.2 solution, drying the substantially pure MgCl.sub.2 solution to produce a MgCl.sub.2 powder containing up to about 5% each of MgO and H.sub.2 O, dehydration melting of the MgCl.sub.2 powder to produce molten anhydrous MgCl.sub.2, performing electrolysis of the molten anhydrous MgCl.sub.2 to produce Mg metal and Cl.sub.2, and recycling all of Cl.sub.2 produced during electrolysis to the above dehydration melting step for converting MgO and H.sub.2 O present in the MgCl.sub.2 powder into MgCl.sub.2 and HCl and for producing the hot HCl-containing gas stream. Dehydration melting is preferably done by feeding the MgCl.sub.2 powder into the feed end of a rotary kiln, and reacting Cl.sub.

Abstract: A process for producing a substantially pure, concentrated MgCl.sub.2 solution suitable for subsequent molten salt electrolysis to magnesium metal from an impure magnesite ore or concentrate is disclosed. The process comprises the steps of calcining a magnesite ore or concentrate at a temperature greater than 600.degree. C. to decompose most of the magnesite and form a reactive magnesia, dissolving such reactive magnesia with either concentrated hydrochloric acid or hydrogen chloride gas with the addition of a surface active wetting agent to produce an impure concentrated MgCl.sub.2 solution, and reacting such impure concentrated MgCl.sub.2 solution with a minimum of excess magnesia to increase the pH of the solution to at least 5.5 to precipitate undesirable impurities from solution and produce a substantially pure MgCl.sub.2 solution.

Abstract: An apparatus for measuring bath temperature of metallurgical furnaces through a tuyere is disclosed. The apparatus comprises a periscope adapted to be inserted into a tuyere, a fiber optic cable having one end connected to the periscope for receiving radiation entering the tuyere from the bath of a furnace, and a two wavelength pyrometer connected to the other end of the fiber optic cable for analysing the radiations transmitted through the fiber optic cable to provide an indication of the temperature of the bath.

Abstract: A method for producing and distributing wet zinc dust to a zinc sulfate purification system or other zinc plant operation is disclosed. The method comprises atomizing molten zinc with high pressure water or other suitable medium, and feeding a predetermined amount of the wet zinc dust to at least one zinc sulphate purification tank or any other zinc plant operation.

Abstract: A method for reducing excessive air inleakage and fuel consumption in open ring-type carbon baking furnaces is disclosed. This method consists in covering the preheat sections of the fire with covers. Each cover is preferably mounted on legs and a flexible sealing skirt is located all around to accommodate the height variations across each furnace section. There are usually more than one preheat section and the covers are identical in construction and dimension to minimize movement of the covers when the fire progresses. To further reduce fuel consumption, covers can also be placed on some of the cooling sections behind the fuel-fired sections and air can be blown or sucked into these sections to force cool these sections and to provide preheated air for combustion in the fuel-fired sections.

Abstract: A voltage monitor is disclosed. The voltage monitor comprises a digital voltmeter for displaying a measured input voltage, and means for converting the varying input voltage of the monitor into a stabilized power supply voltage for the operation of the digital voltmeter. The input voltage is applied to the digital voltmeter through a response time controller providing a long time constant averaging value of input voltage to the digital voltmeter when the input voltage is within a predetermined range about a normal value, and for providing a faster response to input voltage values when the input voltage exceeds its normal value. The voltage is also applied to a stability indicator through an averaging circuit which permits the stability indicator to show short term fluctuations of input voltage about its normal value.