Provided is a mineral processing method that allows obtaining a concentrate having a low arsenic grade from a raw material having a high arsenic grade. The mineral processing method includes: a repulping step of adding water to a raw material containing a non-arsenic-containing sulfide mineral as a sulfide mineral not containing arsenic and an arsenic-containing sulfide mineral as a copper sulfide mineral containing arsenic to obtain a mineral slurry; a pH adjusting step of adjusting a pH of a liquid phase of the mineral slurry to 10 or more; a conditioning step of adding an oxidant and xanthate alkali metal salt to the mineral slurry; and a flotation step of performing flotation using the mineral slurry to separate the raw material into a floating ore having a grade of the non-arsenic-containing sulfide mineral higher than a grade of the non-arsenic-containing sulfide mineral of the raw material and a precipitating ore having a grade of the arsenic-containing sulfide mineral higher than a grade of the arsenic-containing sulfide mineral of the raw material. The raw material contains the arsenic by 4.4 to 5.8 pts. wt. per 100 pts. wt. of copper.

A process for reducing arsenic content from arsenic-bearing gold concentrate or other arsenic-bearing gold materials to produce the low arsenic-bearing gold concentrate. The process comprises: (i) optionally regrinding the input arsenic-bearing gold concentrate; (ii) optionally treating the reground gold concentrate with sulfuric or other aqueous acid in an acidulation step; (iii) adding oxygen, water and/or acid to the acidulated concentrate slurry and reacting them together in an autoclave at an elevated pressure and temperature in a pressure oxidation step; (iv) processing the oxidized concentrate slurry in an arsenic re-dissolution step to dissolve unstable solid arsenic compounds; (v) applying a first solid/liquid separation and wash step, comprising at least one of a thickening step, a counter current decantation (CCD) wash step, and a filter and wash step, to form a first washed slurry/solid and first acid-containing solutions; (vi) reacting the first washed slurry/solid with sulfur dioxide (and optionally sulfuric acid and/or water) in a reductive leach step; (vii) applying a second solid/liquid separation and wash step, comprising at least one of a thickening step, a CCD wash step and a filter and wash step, to form a second washed slurry/solid and second acid-containing solutions, wherein the first and second acid-containing solutions can be recycled to the acidulation and/or pressure oxidation steps; and (viii) applying an optional surface cleaning step, to produce low arsenic bearing gold concentrate.

A process for reducing arsenic content from arsenic-bearing gold concentrate or other arsenic-bearing gold materials to produce the low arsenic-bearing gold concentrate. The process comprises: (i) optionally regrinding the input arsenic-bearing gold concentrate; (ii) optionally treating the reground gold concentrate with sulfuric or other aqueous acid in an acidulation step; (iii) adding oxygen, water and/or acid to the acidulated concentrate slurry and reacting them together in an autoclave at an elevated pressure and temperature in a pressure oxidation step; (iv) processing the oxidized concentrate slurry in an arsenic re-dissolution step to dissolve unstable solid arsenic compounds; (v) applying a first solid/liquid separation and wash step, comprising at least one of a thickening step, a counter current decantation (CCD) wash step, and a filter and wash step, to form a first washed slurry/solid and first acid-containing solutions; (vi) reacting the first washed slurry/solid with sulfur dioxide (and optionally sulfuric acid and/or water) in a reductive leach step; (vii) applying a second solid/liquid separation and wash step, comprising at least one of a thickening step, a CCD wash step and a filter and wash step, to form a second washed slurry/solid and second acid-containing solutions, wherein the first and second acid-containing solutions can be recycled to the acidulation and/or pressure oxidation steps; and (viii) applying an optional surface cleaning step, to produce low arsenic bearing gold concentrate.

Present invention describes a biotechnological procedure to remove magnetic sulfur impurities from iron concentrate, wherein includes: to bioleach iron concentrate ores agglomerated in heaps under temperature condition between 5 and 35 C., inoculating the iron concentrate ores with Acidithiobacillus thiooxidans cultures, with an inoculum concentration 10.sup.4 and 10.sup.6 cel/g and addition of water supplemented with nitrogen and phosphorous source (0.01 to 0.5 g (NH.sub.4).sub.2HPO.sub.4/L), without potassium addition, adjusting pH between 1.0 and 9.0, and a feeding rate between 5 and 15 L/h/m.sup.2; this procedure allows a removal efficiency above 80% in 21 days, with a maximum iron loss of 3%.

Present invention describes a biotechnological procedure to remove magnetic sulfur impurities from iron concentrate, wherein includes: to bioleach iron concentrate ores agglomerated in heaps under temperature condition between 5 and 35 C., inoculating the iron concentrate ores with Acidithiobacillus thiooxidans cultures, with an inoculum concentration 10.sup.4 and 10.sup.6 cel/g and addition of water supplemented with nitrogen and phosphorous source (0.01 to 0.5 g (NH.sub.4).sub.2HPO.sub.4/L), without potassium addition, adjusting pH between 1.0 and 9.0, and a feeding rate between 5 and 15 L/h/m.sup.2; this procedure allows a removal efficiency above 80% in 21 days, with a maximum iron loss of 3%.

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.

A process and reactor for arsenic fixation in which a first gas stream comprises oxygen and an iron-containing particulate material. The oxygen and particulate material may be fed to reactor through respective first and second inlets. A second gas stream containing one or more volatile arsenic compounds is fed through a third inlet and mixed with the first gas stream and the particulate material to produce a combined gas stream containing the volatile arsenic compounds and the particulate material. The arsenic compounds are reacted with iron in the particulate material as the combined gas stream flows through the reactor to produce solid iron arsenates which are then recovered. The portion of the reactor including the first, second and third inlets is vertically oriented, and the reactor may include a venturi arrangement having a throat at which the second inlet is located.

A process and reactor for arsenic fixation in which a first gas stream comprises oxygen and an iron-containing particulate material. The oxygen and particulate material may be fed to reactor through respective first and second inlets. A second gas stream containing one or more volatile arsenic compounds is fed through a third inlet and mixed with the first gas stream and the particulate material to produce a combined gas stream containing the volatile arsenic compounds and the particulate material. The arsenic compounds are reacted with iron in the particulate material as the combined gas stream flows through the reactor to produce solid iron arsenates which are then recovered. The portion of the reactor including the first, second and third inlets is vertically oriented, and the reactor may include a venturi arrangement having a throat at which the second inlet is located.

A process for helping improve hydrometallurgical precious metal recovery from preg-robbing ores or concentrates, such as double refractory ores or concentrates or carbonaceous ores. The process comprises treating the ore or concentrate in the presence of oxygen at a temperature and pressure sufficient to oxidize at least a portion of the organic carbon material in the ore or concentrate. A vessel is used to treat the ore or concentrate to oxidize the organic carbon material. The vessel may be a pipe. The vessel maintains the ore at an elevated temperature and pressure in the presence of oxygen. The vessel may have an inlet for receiving a pre-treated slurry of ore or concentrate, a mechanism for oxygen addition, a mechanism for degassing the pipe reactor, and an outlet for providing the treated slurry to further processing. The vessel may be used in series after an autoclave. The pipe reactor may also include a pre-heating step and a cooling step.

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.