Abstract: There is provided a method for the removal of arsenic from an arsenical bearing sulfides ore, comprising a thermal treatment of arsenical sulfide in the presence of sulfur dioxide, yielding a calcine and a sublimate, the sublimate containing arsenious oxide. The method allows recovering metallic value from an arsenic-bearing metallic sulfides ore, by recovery of the calcine comprising the metallic value of the ore.

Abstract: The present disclosure broadly relates to a process for recovering magnesium as magnesium oxide and fibrous amorphous silica from serpentinite feedstocks. More specifically, but not exclusively, the present disclosure relates to metallurgical and chemical processes for recovering magnesium oxide and fibrous amorphous silica from serpentinite feedstocks. The process broadly comprises applying a sufficient amount of shear deformation force to the serpentine feedstocks to produce a particulate material of reduced size; subjecting the particulate material to magnetic separation to produce a primary magnetic separation product and iron-reduced tailings; and digesting the iron-reduced tailings into nitric acid, producing a magnesium-rich pregnant solution and insoluble solids. The process further comprises adjusting the pH of the pregnant solution to values ranging from about 5.0 to about 7.0.

Abstract: A method of fabrication of arsenic glass, comprising forming pellets of an arsenic-containing glass-forming mixture comprising arsenic in a range between about 30 and about 50% w/w and glass forming elements, and melting the pellets by direct heating to a temperature in a range between about 950 and about 1250° C.

Abstract: A method for producing a double sulfate of potassium and magnesium by dry mechanical attrition of potassium sulfate and magnesium sulfate hexahydrate, comprising obtaining potassium sulfate by sulfatation of potash to bisulfate of potassium and disproportionation of the bisulfate of potassium to potassium sulfate in a water-methanol solution, and obtaining magnesium sulfate hexahydrate by sonic-assisted partial sulfatation of calcined serpentinic silicate.

Abstract: A method and a system for gold and silver recovery from a pregnant solution resulting from gold extraction from an ore using halogen, the method comprising lowering the oxidation reduction potential of the pregnant solution by mixing the pregnant solution with a reducer over the surface of a bed of silica, and flowing the mixture through the bed of silica. The system comprises a bed of silica, a feeder controlling feeding of the pregnant solution with a reducer to direct a mixture of an ORP less than 550 mV to the surface of the bed of silica, and a collector receiving a barren solution from the bed of silica after flowing of the mixture therethrough.

Abstract: A method of fabrication of arsenic glass, comprising forming pellets of an arsenic-containing glass-forming mixture comprising arsenic in a range between about 30 and about 50% w/w and glass forming elements, and melting the pellets by direct heating to a temperature in a range between about 950 and about 1250° C.

Abstract: A method for producing a double sulfate of potassium and magnesium by dry mechanical attrition of potassium sulfate and magnesium sulfate hexahydrate, comprising obtaining potassium sulfate by sulfatation of potash to bisulfate of potassium and disproportionation of the bisulfate of potassium to potassium sulfate in a water-methanol solution, and obtaining magnesium sulfate hexahydrate by sonic-assisted partial sulfatation of calcined serpentinic silicate.

Abstract: There is provided a method for the removal of arsenic from an arsenical bearing sulfides ore, comprising a thermal treatment of arsenical sulfide in the presence of sulfur dioxide, yielding a calcine and a sublimate, the sublimate containing arsenious oxide. The method allows recovering metallic value from an arsenic-bearing metallic sulfides ore, by recovery of the calcine comprising the metallic value of the ore.

Abstract: A method for vitrification of arsenic and antimony, comprising substituting oxygen to sulfur on thiosalts, incorporating resulting sodium arsenate and sodium antimonate into a sodium silicate glass-forming mixture and vitrifying the sodium silicate glass-forming mixture into a resulting glass sequestering the arsenic and antimony.

Abstract: A method for vitrification of arsenic and antimony, comprising substituting oxygen to sulfur on thiosalts, incorporating resulting sodium arsenate and sodium antimonate into a sodium silicate glass-forming mixture and vitrifying the sodium silicate glass-forming mixture into a resulting glass sequestering the arsenic and antimony.

Abstract: There is provided a method and composition for sequestration of arsenic, the method comprising melting an arsenic-containing material in the presence of iron oxide and glass, and yielding a resulting glass incorporating arsenic. The resulting glass has an arsenic content comprised in a range between 1 and 25% w/w and an iron content comprised in a range between 8 and 20% w/w.

Abstract: A method for formation of scorodite and for stabilization of arsenic by formation of scorodite, comprising using sodium hypochlorite as an oxidizing agent. The method comprises producing sodium hypochlorite having a concentration in a range between 1 and 3 w/w % using a diaphragm-less electrolytic cell operating with a sodium salt solution having a salt concentration in a range between 2 and 10 w/w %; diluting a sodium hypochlorite solution to less than 1 w/w % in an arsenic solution at an oxydo reduction potential in a range between 900 and 1100 mV (Pt, AgCl reference) and a pH comprised in range between 0.5 and 2.0; contacting a resulting oxidized arsenic with a ferric salt; and raising the pH to 5.

Abstract: There is provided a method and composition for sequestration of arsenic, the method comprising melting an arsenic-containing material in the presence of iron oxide and glass, and yielding a resulting glass incorporating arsenic. The resulting glass has an arsenic content comprised in a range between 1 and 25% w/w and an iron content comprised in a range between 8 and 20% w/w.

Abstract: A method for producing potassium-based fertilisers, comprising using potassium acid sulfate as the potassium source, and using sonication in reactions with magnesium silicate or apatite at low temperature, with near quantitative yield, to yield in times of the order of minutes the corresponding potassium magnesium sulfate or potassium di-hydrogen phosphate respectively.

Abstract: A method for selectively processing a polymetallic oxide solution containing a plurality of base metals comprising at least one of: Cu, Co, Ni, Zn associated with iron, comprising acid leaching the solution; recovering a filtered leachate; oxidizing the leachate; and adjusting the pH of the leachate in presence of a complexing agent; wherein the acidic solution is one of: i) a hydrochloric acid solution and ii) a sulfuric acid solution at a pH lower than about 1.5, and the complexing agent is one of: i) ammonium chloride and ii) ammonium sulfate, the step of adjusting the pH comprising raising the pH to a range between about 2.5 and about 3.5.

Abstract: A method for extracting precious metals from a polymetallic ore, comprising a) generating hypochlorites from a salt brine; b) chlorination of the ore using hypochlorites under acidic conditions; c) filtering to collect a pregnant solution and treating the pregnant solution for collection of precious metals; d) filtering to separate the precious metals and a barren brine; e) purifying the barren brine; and f) recycling halogens from the purified brine in the form of hypohalites formed by electrolysis of the purified brine, and comprising hypochlorite and hypobromite; step b) further comprising scrubbing excess halogens using calcium hydroxide; treating the pregnant solution in step c) comprises reducing an oxydo reduction potential of the pregnant solution and using calcium hydroxide for neutralization; and step e) comprising increasing the pH of the barren brine by addition of calcium hydroxide.

Abstract: A method for recovering precious metal from an acidic pregnant solution resulting from halogen or hypohalite leaching of an ore, comprising lowering the ORP of the pregnant leachate with a reducing agent in the presence of slurried non-carboneous particles. The precious metal deposits on the surfaces of the particles and a barren solution comprising substantially all the halogen values of the pregnant solution in the form of sodium chloride, sodium bromide or hypohalites is recovered.

Abstract: There is thus provided a method allowing the recovery of metallic values from laterites by the action of rather diluted sulfuric acid on nickel and cobalt-bearing laterites, at atmospheric pressure and near ambient temperature, assisted by ultrasonic treatment. With an acid concentration in the range for example between about 25 and about 50 weight % of sulfuric acid, under atmospheric pressure, sonication, extracting metallic values from the slurried laterites is thus achieved at room temperature.

Abstract: A method for extracting precious metals from a polymetallic ore, comprising a) generating hypochlorites from a salt brine; b) chlorination of the ore using hypochlorites under acidic conditions; c) filtering to collect a pregnant solution and treating the pregnant solution for collection of precious metals; d) filtering to separate the precious metals and a barren brine; e) purifying the barren brine; and f) recycling halogens from the purified brine in the form of hypohalites formed by electrolysis of the purified brine, and comprising hypochlorite and hypobromite; step b) further comprising scrubbing excess halogens using calcium hydroxide; treatng the pregnant solution in step c) comprises reducing an oxydo reduction potential of the pregnant solution and using calcium hydroxide for neutralization; and step e) comprising increasing the pH of the barren brine by addition of calcium hydroxide.

Abstract: The invention relates to a method for the extraction of precious metals, using halogens. It has been found that introducing halogens in the reactor in the form of hypohalites rather than free halogens simplified greatly the recycling of halogens by electrolysis. It increases the rate of addition of the halogens and significantly reduces secondary reactions with base metals such as iron. Operating under acidic conditions, the gold recovery has been found as high with hypochlorite as with elemental chlorine, with an active chlorine to ore ratio reduced by a factor of two to five.