The invention relates to a method for removing and stabilising arsenic from effluents from metallurgical processes, which comprises the following steps: (i) a first step of reducing arsenic from an arsenic-containing effluent from metallurgical processes, wherein the arsenic is preferably in the form of arsenic (III), to which sulphide is added to reduce the arsenic in order to form a first arsenic residue pulp; (ii) a second step in which the first arsenic residue pulp obtained in step (i) is subjected to a first step of separating solids from liquids, obtaining a first arsenic residue and a first treated effluent; (iii) a third step in which ferric oxyhydroxide with a particle size of 212-2000 µm is mixed with the first arsenic residue to obtain a second arsenic residue; and (iv) a fourth step in which the second arsenic residue obtained in step (iii) is subjected to a process of calcinating, thereby obtaining a stable arsenic residue.
The invention discloses a process for the stabilization of arsenical waste by means of the precipitation of tooeleite by thermal stabilization, the process comprising the following steps: a first step of neutralization, in which the arsenical effluent is brought into contact with a first neutralizer to generate a first neutralized arsenical effluent; a second step of Fe(III)/As(III) ratio adjustment, in which the first neutralized arsenical effluent is mixed with a first ferric solution, to generate a third arsenic effluent; a third step of arsenic precipitation, in which the pH of the third arsenical effluent is adjusted with a second neutralizer to generate a first arsenical residue slurry; a fourth step of solid-liquid separation, in which the first arsenical residue slurry is separated to generate a fourth arsenical effluent and a first arsenical residue; a fifth step of calcination, in which the first arsenical residue is calcined to generate a second arsenical residue; a sixth step of washing, in which the second arsenical residue is washed with an aqueous solution to generate a second arsenical residue slurry; and a seventh step of solid-liquid separation, in which the second arsenical residue slurry is separated to generate a fifth arsenical effluent and a third stable arsenical residue in the form of tooeleite. The invention solves the technical problem of removing arsenic from arsenical effluents to generate stable arsenical residues which, for their synthesis, do not require an oxidation step to oxidize the arsenous ion to arsenate ion, nor the application of heat in the precipitation step.
A procedure for the stabilization of arsenic by precipitation of ferric arsenate in mixtures with aluminum gel, the procedure comprising the following steps: i) neutralization of an arsenical effluent with a first neutralizer to generate a neutralized arsenical effluent; ii) oxidation of effluent from step i by addition of a first oxidizer, wherein As(lll) is oxidized to As(V) (iii) Fe(lll)/As(V) molar ratio adjustment, where the oxidized arsenic effluent from step ii is mixed with a ferric solution iv) arsenic precipitation, where the pH of the arsenic effluent from step iii is adjusted with a second neutralizer to generate a arsenic residue slurry; v) arsenical residue slurry obtained from step iv) is separated to generate an effluent and a first arsenical residue; and vi) mixing the arsenical residue obtained in step v) with a gel to generate a second arsenical residue.
C02F 1/72 - Treatment of water, waste water, or sewage by oxidation
A62D 3/30 - Processes for making harmful chemical substances harmless, or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
A62D 3/33 - Processes for making harmful chemical substances harmless, or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by chemically fixing the harmful substance, e.g. by chelation or complexation
A62D 3/38 - Processes for making harmful chemical substances harmless, or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by oxidationProcesses for making harmful chemical substances harmless, or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by combustion
C02F 3/00 - Biological treatment of water, waste water, or sewage
4.
METHOD FOR THERMALLY STABILIZING ARSENIC SULFIDES IN MIXTURES WITH SULFUR
The present invention discloses a process for removal and stabilization of arsenic from metallurgical process effluents: (i) abatement of arsenic from an arsenic-containing metallurgical process effluent, to which sulfide is added to form a first arsenic residue slurry, (ii) where the first arsenic residue slurry is subjected to a first solid-liquid separation stage, obtaining a first arsenic residue and a first treated effluent, (iii) where the first arsenic residue is mixed with sulfur (SO), water and sulfuric acid at a concentration between 70 and 150 g/L and is subjected to a thermal stabilization stage at between 20-90°C for between 15 min and 18 h, to form a second arsenic residue slurry (iv) where the second arsenic residue slurry obtained in (iii) is separated into a stable arsenic residue and a first arsenic solution that is recirculated to stage (i) of arsenic abatement.
A procedure for leaching copper and lead from metallurgical residues of smelting powders which have been subjected to a process of copper leaching and comprising copper, iron, lead, silicon, and optionally arsenic, antimony and bismuth, comprising: (i) copper leaching with a first acid solution of the metallurgical residue, in order to obtain a first leaching solution rich in copper and iron, and optionally arsenic, antimony and bismuth and a first leached sludge having a content reduced in copper and iron, and optionally reduced in arsenic and rich in lead and silicon, (ii) leaching the first leached sludge with a first solution of a carboxylic acid salt, in order to obtain a second leached sludge deficient of lead and a second leaching solution rich in lead, (iii) precipitation wherein a first base is added to the second leaching solution rich in lead in order to obtain a first lead concentrate, and a first precipitation solution deficient of lead, (iv) alkaline leaching of the second leached sludge, wherein a second base is added in order to form an alkaline leaching solution, in order to obtain a third leached sludge having a content reduced in silicon, and a third leaching solution rich in silicon, and optionally arsenic, (v) hydrochloric leaching of the third leached sludge, wherein an acid solution is used in chloride environment, in order to obtain a fourth leached sludge for final disposal and a fourth leaching solution rich in copper, lead and iron, and optionally arsenic, (vi), (vii) metal precipitation from the fourth leaching solution rich in copper, lead and iron, and optionally arsenic with a neutralizing slurry, in order to produce a fifth solution rich in chloride and a first precipitate solid rich in iron, copper and lead, and optionally arsenic, and ( viii) leaching the first precipitate solid rich in iron, copper and lead, and optionally arsenic with a sulfuric acid solution, in order to produce a sixth leaching solution rich in copper, iron and optionally arsenic, and a second lead concentrate.
Procedure for producing germanium concentrate from metallurgical residues, comprising: (i) copper leaching with a first acid solution of the metallurgical residue, in order to obtain a first leaching solution rich in copper and iron, and a first leached sludge having a content reduced in copper and iron, (ii) leaching the first leached sludge wherein said first leached sludge is processed with a first solution of sodium citrate, in order to obtain a second leached sludge deficient of lead and a second leaching solution rich in lead, (iii) alkaline leaching of the second leached sludge, wherein a base is added in order to form an alkaline leaching solution, in order to obtain a third leached sludge having a content reduced in silicon and germanium and a third leaching solution rich in germanium and silicon, (iv) charging in an ion exchange column, wherein the germanium is captured by the resin, in order to obtain a fourth alkaline solution deficient of germanium and rich in silicon.
A procedure for producing silver concentrate from metallurgical residues containing copper, iron, lead, silicon, silver and antimony; (i) copper leaching with an acid solution of the metallurgical residue yielding a first leached sludge; (ii) leaching the first sludge with a first solution of a carboxylic acid salt to obtain a second sludge deficient of lead; (iii) alkaline leaching of the second sludge to obtain a third sludge having a content reduced in silicon; (iv) hydrochloric leaching of the third \sludge to obtain a fourth sludge; (v) silver precipitation from the fourth leaching solution rich in silver to produce a first precipitate rich in iron, copper, lead and silver (vi) leaching the first precipitate with a sulfuric acid solution, in order to produce a first silver and lead concentrate, and (viii) leaching the first silver concentrate with a second carboxylic acid salt solution, in order to produce a second silver concentrate.
A technical problem that has not been solved, is that today there is no procedure by which a final residue containing scorodite stabilized with a high arsenic content, higher than 15 % from highly acidic solutions greater than 30 g/L of free acidity or pH below 1.0. The present invention provides a solution to this problem through a process that allows: the oxidation of trivalent arsenic and ferrous ion, simultaneous with neutralization of the acid solution to be treated, the precipitation of arsenic and oxidized ferric iron added in a molar ratio Fe:As determined at a defined pH, all of the above with a high efficiency of precipitation of arsenic as ferric arsenate or scorodite, obtaining a final residue stable in the long term, characterized by their higher content of arsenic in a lower volume compared with the procedures described in the state of the prior art.
The present invention provides a process that allows the oxidation of trivalent arsenic and ferrous ion, simultaneous with neutralization of the acid solution to be treated, the precipitation of arsenic and oxidized ferric iron added in a molar ratio Fe:As determined at a defined pH, all of the above with a high efficiency of precipitation of arsenic as ferric arsenate or scorodite, obtaining a final residue stable in the long term, characterized by their higher content of arsenic in a lower volume compared with the procedures described in the state of the prior art.
C02F 103/10 - Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
C02F 103/34 - Nature of the water, waste water, sewage or sludge to be treated from the chemical industry not provided for in groups
10.
Process for recovery of technical grade molybdenum from diluted leaching acid solutions (PLS), with highly concentrated arsenic, from metallurgical residues
A method for recovering technical-grade molybdenum from diluted acid leaching solutions (PLS) that have a high arsenic concentration is disclosed. The method includes: (a) contacting a pre-filtered PLS with an anionic ion-exchange resin; (b) washing the loaded resin with water; (c) extracting molybdenum from the resin with an alkaline ammonium regenerant solution to form ammonium molybdenum in solution; (d) washing the unloaded resin with water; (e) adding iron and/or magnesium salts to the recovered ammonia solution to obtain a precipitate which is transferred to the arsenic abatement step and a solution containing ammonium molybdate; (f) adding sulphuric acid to the arsenic-free ammonia solution to precipitate ammonium molybdate; (g) separating the precipitate by filtering the molybdate and re-circulating the solution obtained with the initial PLS; (h) calcining the separated precipitate to obtain ammonia and molybdenum trioxide; and (i) recovering the released ammonia for subsequent use as a recirculated regenerant solution.
C22B 3/42 - Treatment or purification of solutions, e.g. obtained by leaching by ion-exchange extraction
11.
METHOD FOR RECOVERING TECHNICAL-GRADE MOLYBDENUM FROM DILUTED ACID LEACHING SOLUTIONS (PLS) THAT HAVE A HIGH ARSENIC CONCENTRATION AND ORIGINATE FROM METALLURGICAL WASTE
The invention relates to a method for recovering technical-grade molybdenum from diluted acid leaching solutions (PLS) that have a high arsenic concentration, said method comprises the following steps consisting in: (a) bringing a pre-filtered acid leaching solution (PLS), originating from the leaching of smelter dust, into contact with an anionic ion-exchange resin; (b) washing the loaded resin with water; (c) extracting the molybdenum from the ion-exchange resin with an alkaline ammonium regenerant solution at a pH value of between 8 and 12, in order to form ammonium molybdenum in solution; (d) washing the unloaded resin with water; (e) adding iron and/or magnesium salts to the recovered ammoniacal solution, in order to obtain a precipitate which is transferred to the arsenic abatement step and a solution containing ammonium molybdate in solution; (f) adding sulphuric acid to the arsenic-free ammoniacal solution in order to precipitate the moylbdenum in the form of ammonium molybdate in an acid environment at a pH value of between 1.5 and 4; (g) separating the precipitate formed by filtering the molybdate and re-circulating the solution obtained with the initial PLS solution; (h) calcining the separated precipitate in order to obtain ammonia and molybdenum trioxide; and (i) recovering the released ammonia for its subsequent use in the method as a recirculated regenerant solution.
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