ELECTROCHEM TECHNOLOGIES & MATERIALS INC. (Canada)
Inventor
Cardarelli, François
Abstract
The present disclosure broadly relates to a high temperature chemical process for the synthesis of cesium tungstate in the solid state and the preparation of aqueous solutions or deuterated solutions of cesium tungstate. More specifically, but not exclusively, the present disclosure relates to a high temperature chemical process in which tungsten oxide compounds such as tungsten oxides, or natural or synthetic concentrates such as wolframite or scheelite, tungsten industrial by-products or there mixture thereof, are mixed with cesium compounds such as cesium carbonate, or cesium sulfate, or cesium hydroxide or their mixtures thereof and the mixture is roasted in air or oxygen at high temperature inside a kiln. After cooling, the solid sintered mass containing cesium tungstate is leached or dissolved with water or heavy water for producing dense aqueous solutions or deuterated solutions of cesium tungstate.
ELECTROCHEM TECHNOLOGIES & MATERIALS INC. (Canada)
Inventor
Cardarelli, François
Abstract
The present disclosure broadly relates to a process for preparing aqueous solutions of vanadium sulfates or aqueous solutions of transition metal sulfates. More specifically, but not exclusively, the present disclosure relates to a direct electrochemical process in which a suspension, obtained by slurrying transition metals oxides such as oxides of vanadium, oxides of iron, oxides of cobalt, oxides of nickel, oxides of chromium, oxides of manganese, oxides of titanium, oxides of cerium, oxides of praseodymium, oxides of europium, oxides of terbium, oxides of uranium, oxides of plutonium, or their mixtures thereof with sulfuric acid as carrier fluid, is reduced electrochemically inside the cathode compartment of an electrolyzer to produce an aqueous solution of vanadium sulfates or of transition metal sulfates. Simultaneously, oxidizing co-products are produced in the anode compartment.
ELECTROCHEM TECHNOLOGIES & MATERIALS INC. (Canada)
Inventor
Cardarelli, François
Abstract
The present disclosure broadly relates to a process for recovering vanadium, iron, titanium and silica values from vanadiferous feedstocks. More specifically, but not exclusively, the present disclosure relates to a metallurgical process in which vanadium, iron, titanium and silica values are recovered from vanadiferous feedstocks such as vanadiferous titanomagnetite, iron ores, vanadium slags and industrial wastes and by-products containing vanadium. The process broadly comprises digesting the vanadiferous feedstocks into sulfuric acid thereby producing a sulfation cake; dissolving the sulfation cake and separating insoluble solids thereby producing a pregnant solution; reducing the pregnant solution thereby producing a reduced pregnant solution; and crystallizing ferrous sulfate hydrates from the reduced pregnant solution, producing an iron depleted reduced solution. The process further comprises removing titanium compounds from the iron depleted reduced solution thereby producing a vanadium-rich pregnant solution; concentrating vanadium and recovering vanadium products and/or a vanadium electrolyte.
ELECTROCHEM TECHNOLOGIES & MATERIALS INC. (Canada)
Inventor
Cardarelli, Francois
Abstract
The present disclosure broadly relates to a novel process for the recovery of rare earths oxides from phosphors, fluorescent lamps and light bulbs, cathode ray tubes and other industrial wastes containing rare earths elements in the form of halophosphates, tri-band phosphors and other fluorescent materials, the process comprising: a) submitting the wastes or spent materials to either caustic fusion or hot alkaline leaching; b) submitting the solidified melt to hot alkaline leaching step to produce insoluble solid residues and a barren alkaline leaching solution; c) crystallizing the tri-sodium phosphate from the barren solution; d) oven-drying or calcining the residues; e) acid leaching the oven-dried or calcined solids; f) recovering the cerium (IV) oxide from insoluble solids; g) reducing the cerium-free solution, precipitating, acid leaching, precipitating, calcining and recovering the europium (III) oxide; h) precipitating the remaining rare earths as oxalates; i) calcining the rare earths oxalates and dissolving the rare earths oxides in acid; j) separating the yttrium, gadolinium, terbium and erbium by ion exchange (IX) or solvent extraction (SX); h) precipitating and calcining to yield pure yttrium (III) oxide, gadolinium (III) oxide, terbium (III, IV) oxides, and erbium (III) oxide; i) regenerating and recycling the spent alkaline solution after causticization with calcium oxide or hydroxide.
ELECTROCHEM TECHNOLOGIES & MATERIALS INC. (Canada)
Inventor
Cardarelli, Francois
Abstract
The present disclosure broadly relates to a novel process for the recovery of rare earths oxides from phosphors, fluorescent lamps and light bulbs, cathode ray tubes and other industrial wastes containing rare earths elements in the form of halophosphates, tri-band phosphors and other fluorescent materials, the process comprising: a) submitting the wastes or spent materials to either caustic fusion or hot alkaline leaching; b) submitting the solidified melt to hot alkaline leaching step to produce insoluble solid residues and a barren alkaline leaching solution; c) crystallizing the tri-sodium phosphate from the barren solution; d) oven-drying or calcining the residues; e) acid leaching the oven-dried or calcined solids; f) recovering the cerium (IV) oxide from insoluble solids; g) reducing the cerium-free solution, precipitating, acid leaching, precipitating, calcining and recovering the europium (III) oxide; h) precipitating the remaining rare earths as oxalates; i) calcining the rare earths oxalates and dissolving the rare earths oxides in acid; j) separating the yttrium, gadolinium, terbium and erbium by ion exchange (IX) or solvent extraction (SX); h) precipitating and calcining to yield pure yttrium (III) oxide, gadolinium (III) oxide, terbium (III, IV) oxides, and erbium (III) oxide; i) regenerating and recycling the spent alkaline solution after causticization with calcium oxide or hydroxide.
ELECTROCHEM TECHNOLOGIES & MATERIALS INC. (Canada)
Inventor
Cardarelli, Francois
Abstract
A process for upgrading tantalum and niobium ores and concentrates is described herein. The process comprising: a) submitting the ore or concentrate to a caustic fusion or an alkali fusion using a melt comprising at least one salt of an alkali metal to produce a solidified melt; b) submitting the solidified melt to an alkaline leaching step to produce an alkaline pregnant leaching solution comprising manganese values; c) recovering the manganese values from the alkaline pregnant leaching solution to produce a substantially manganese-free leach solution; and d) precipitating tantalum and niobium as an insoluble niobiate and tantalate from the manganese-free leach solution. The rare earth oxides are recovered from the insoluble residues obtained during alkaline leaching.
C22B 1/00 - Preliminary treatment of ores or scrap
C22B 3/12 - Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic alkaline solutions
C22B 3/22 - Treatment or purification of solutions, e.g. obtained by leaching by physical processes, e.g. by filtration, by magnetic means
C22B 9/10 - General processes of refining or remelting of metalsApparatus for electroslag or arc remelting of metals with refining or fluxing agentsUse of materials therefor
C22B 3/06 - Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions
ELECTROCHEM TECHNOLOGIES & MATERIALS INC. (Canada)
Inventor
Cardarelli, Francois
Abstract
An electrochemical process for the recovery of metallic iron or an iron-rich alloy, oxygen and sulfuric acid from iron-rich metal sulfate wastes is described. Broadly, the electrochemical process comprises providing an iron-rich metal sulfate solution; electrolyzing the iron-rich metal sulfate solution in an electrolyzer comprising a cathodic compartment equipped with a cathode having a hydrogen over- potential equal or higher than that of iron and containing a catholyte having a pH below about 6.0; an anodic compartment equipped with an anode and containing an anolyte; and a separator allowing for anion passage; and recovering electrodeposited iron or iron-rich alloy, sulfuric acid and oxygen gas. Electrolyzing the iron-rich metal sulfate solution causes iron or an iron-rich alloy to be electrodeposited at the cathode, nascent oxygen gas to evolve at the anode, sulfuric acid to accumulate in the anodic compartment and an iron depleted solution to be produced.
