Abstract: The present invention relates to an electrolytic process for producing metallic lead starting from desulfurized lead pastel comprising the following operative phases: a) leaching the desulfurized pastel by putting it in contact with a solution comprising ammonium chloride, with the formation of a leach liquor and evolution of gaseous CO2; b) separating a first solid residue and a first clarified leach liquor from the leach liquor coming from phase a); c) leaching the solid residue separated in phase b) by putting it in contact with a solution comprising ammonium chloride and hydrogen peroxide; d) separating a second solid residue and a second clarified leach liquor from the leach liquor coming from phase c); e) joining the first clarified leach liquor coming from phase b) with the second clarified leach liquor coming from phase d) and forming a single solution; f) subjecting the solution leaving phase e) to electrolysis in a flow cell, with a current density ranging from 50 to 10,000 A/m2, said electrolysis r

Abstract: The present invention relates to a process for the recovery of elemental sulphur from residues produced in hydrometallurgical processes based on leaching with a solution of sodium sulphide in which the sulphur contained in the residues is selectively leached as sodium polysulphide. The sulphur leaching solution is conveniently regenerated and recycled to the process.

Abstract: The present invention relates to a desulfurization process of pastel and grids of lead accumulators comprising a carbonation in two steps, a granulometric separation between the two steps followed by specific desulfurization of the large part, a desodification obtaining the conversion of the PbSO4 contained in the pastel into PbCO3 which can be easily converted into metallic Pb in an oven by the addition of coal. The system used for the desodification of the large part of the pastel can also be used for the desulfurization of the fine part of the grids.

Abstract: The present invention relates to a process for the recovery of elemental sulphur from residues produced in hydrometallurgical processes based on leaching with a solution of sodium sulphide in which the sulphur contained in the residues is selectively leached as sodium polysulphide. The sulphur leaching solution is conveniently regenerated and recycled to the process.

Abstract: The present invention relates to a desulfurization process of pastel and grids of lead accumulators comprising a carbonation in two steps, a granulometric separation between the two steps followed by specific desulfurization of the large part, a desodification obtaining the conversion of the PbSO4 contained in the pastel into PbCO3 which can be easily converted into metallic Pb in an oven by the addition of coal. The system used for the desodification of the large part of the pastel can also be used for the desulfurization of the fine part of the grids.

Abstract: The present invention relates to a process for recovering metals, in particular precious metals, from electronic scrap, comprising a leaching phase in which the electronic scrap is treated with a leaching solution based on cupric chloride and an alkaline chloride to dissolve the metals exposed to said solution, with the exception of gold, and a subsequent recovery phase of gold in solid form.

Abstract: A process is disclosed for treating lead paste from exhausted batteries. Calcium sulfite and calcium thiosulfite are formed by the reaction:3Ca(OH).sub.2 +4S.degree..fwdarw.2CaS+CaS.sub.2 O.sub.3 +3H.sub.2 O(1).The CaS and CaS.sub.2 O.sub.3 is reacted with sodium sulfate to effect the double exchange reaction:2CaS+CaS.sub.2 O.sub.3 +3Na.sub.2 SO.sub.4 .fwdarw.2Na.sub.2 S+Na.sub.2 S.sub.2 O.sub.3 +3CaSO.sub.4 (2).The sodium sulfide and sodium thiosulfate is then reacted with the lead paste for converting the various lead paste components (PbSO.sub.4, PbO and PbO.sub.2) into PbS with the concomitant production of sodium sulfate. The sodium sulfate can be recycled to reaction (2).

Abstract: A hydrometallurgic and electrochemical process for processing sulfur antimony ores and residues is disclosed, the end products from which are electrolytic antimony and elemental sulfur. The concentrate of sulfur antimony ore, leached with a solution of caustic alkali according to the known techniques dissolves, as sulfur salts as much Sb as possible, whilst the other heavy and precious metals which accompany the antimony bearing ore remain unchanged in the residue. From the solution of antimony sulfur salts pure Sb.sub.2 S.sub.3 is precipitated by acidification and this sulfide, separated from the solution by filtration, is leached with a ferric fluoborate based electrolyte which oxidizes sulfide into elemental sulfur and dissolves antimony as Sb.sup.3+ fluoborate.

Abstract: A method for manufacturing a hardened lead storage battery electrode wherein fine, particulate solids, that are insoluble in lead, are incorporated into a lead matrix. The method includes the steps of incorporating solids, dissolved or suspended in an electrolyte, into a lead matrix such that shaping simultaneously occurs during the deposition of lead due to a suitable fashioning of a plurality of electrically conductive surface regions; vigorously agitating the electrolyte by introducing air through an apertured plate in the bottom of an electrolyte vessel providing an electro-chemical cell including a cathode and a Cu/Ta/Pt anode and an electrolyte solution including HBF.sub.4 and an electrolyte selected from PbO, Pb(OH).sub.2 and PbCO.sub.3 or including a graphite anode and an electrolyte solution of Fe(BF.sub.4).sub.2 and Fe(BF.sub.4).sub.3. The electrolyte is prepared from a raw material selected from lead, waste material containing lead and desulfured lead storage battery electrolyte paste.

Abstract: A wet process of regenerative type for removing SO.sub.2 contained in combustion gases in which SO.sub.2 is caused to be absorbed by a diluted aqueous solution of BaS, with a mixed precipitate of elemental S, BaSO.sub.3 and BaSO.sub.4 being formed by the consequent reactions. Sulfur is extracted from the precipitate--recovered by filtration--by using a solution of (NH.sub.4).sub.2 S; the resulting polysulfide is distilled, with pure elemental S and the solution of (NH.sub.4).sub.2 S to be recycled, being obtained. The residual mixture of BaSO.sub.3 and BaSO.sub.4 remaining after sulfur extraction is reduced with coal in a high temperature furnace, in order to obtain BaS to be recycled, as an aqueous solution, to the SO.sub.2 absorption step.

Abstract: Raw lead to be refined, whether of mineral origin or from reclaiming operations, the particle size of which has been reduced to a range not larger than 50 mm, is leached in a suitable apparatus with a solution of ferric fluoroborate in fluoroboric acid. During the leaching step, lead is dissolved, with ferric fluoroborate being reduced to ferrous fluoroborate according to the following reaction:2Fe(BF.sub.4).sub.3 +Pb.fwdarw.Pb(BF.sub.4).sub.2 +2Fe(BF.sub.4).sub.2The leaching apparatus behaves as an external anode installed outside of the cell. The solution resulting from the leaching step is sent to the cathodic compartment of a diaphragm cell in which lead is deposited on a cathode of stainless steel, in compact, highly pure form. The solution that is depleted of lead then is sent to the anodic compartment of the same cell, in which a suitable anode oxidizes ferrous fluoroborate to ferric fluoroborate that can be regenerated to the leaching step.

Abstract: An insoluble anode is for the electrowinning of heavy metals from aqueous solutions which contain them, and for the electrolytic production of oxidizer halogenated salts.The anode includes a copper bar acting as a bus bar (i.e., as a current-bearing bar), having vertical and horizontal holes through which fork-shaped elements, made from a bimetallic conductor, are inserted and fastened. A plurality of fork-shaped elements, made from the filamentary bimetallic conductor, coated by a catalytic layer of Pt and/or PbO.sub.2, act as an electrode with preferential oxygen development. A framework made from an insulating plastics material, is for supporting and stiffening the structure, and for the precise positioning of the anode inside the cell.

Abstract: A process is disclosed for recovering the components of spent lead acid batteries of the type comprising an active mass desulphurization stage in which sodium sulphate is formed, characterized in that the sodium sulphate solution thus formed is fed to an electrolysis stage in which a soda solution is produced at the cathode and a sulphuric acid solution is produced at the anode. The soda solution produced at the cathode is recycled to the active mass desulphurization stage, and the sulphuric acid solution produced at the anode is recovered for reuse as battery electrolyte in the production of new lead acid batteries.

Abstract: A process for producing electrolytic lead and elemental sulfur from galena comprises the steps of leaching galena with an acidic aqueous solution of ferric fluoborate, with ferrous fluoborate, lead fluoborate, and elemental sulfur being formed according to the reaction:2 Fe(BF.sub.4).sub.3 +PbS.fwdarw.2 FE(BF.sub.4).sub.2 +Pb(BF.sub.4).sub.2 +S.In a further step, a solid residue produced in the leaching step is filtered off, the solid residue comprising elemental sulfur and galena gangue. The solution of ferrous fluoborate and lead fluoborate formed in the leaching step is subjected to electrolysis in a diaphragm electrolytic cell in which pure lead is deposited at a cathode of the cell and ferrous ions are oxidated to ferric ions at an anode of the cell. A solution of ferric fluoborate regenerated at the anode in the electrolysis step is recycled to the leaching step so that the solution is subjected to the galena leaching step.

Abstract: An electrical conductor is particularly suitable for use as an insoluble anode in electrowinning processes, and is composed of an inner core of copper coated with an outer, thinner layer of a transition metal, preferably selected from among tantalum, titanium and niobium. The conductor is manufactured by a process including the steps of inserting a copper bar inside a relatively thin tube made of the selected transition metal, inserting the tube containing the copper bar inside a copper tube to obtain a three-metal structure, submitting the three-metal structure to a drawing process to produce a three metal wire, and dipping the three-metal wire in a solvent to remove the outer copper layer to produce a bimetallic wire.

Abstract: The present invention relates to a process and a plant for the processing of saline slag from the melting of aluminium scrap and waste with a saline flux in which the salts constituting the flux are recovered and other components of the slag are separated. The harmful or toxic gases developed during this processing are subjected to combustion to produce flue gases dispersible in the atmosphere with recovery of combustion heat, preferably used over in processing the slag.

Abstract: A process for recovering in pure metal form substantially all lead from battery sludge is disclosed. The battery sludge is desulfurized, leached with acid, and separated by filtration. Lead is recovered from the filtrate by electrowinning. The residue from the leaching and filtration is treated with concentrated sulfuric acid to cause the simultaneous occurring of the following reactions:C.sub.n (H.sub.2 O).sub.m +H.sub.2 SO.sub.4 .fwdarw.nC+H.sub.2 SO.sub.4 .multidot.mH.sub.2 O (1)C+2PbO.sub.2 +2H.sub.2 SO.sub.4 .fwdarw.2PbSO.sub.4 +CO.sub.2 +2H.sub.2 O (2)up to the quantitative reduction of substantially all of the lead dioxide PbO.sub.2 and elimination of substantially all the organic substances C.sub.n (H.sub.2 O).sub.m contained in the insoluble residue. Lead sulfate from the above reaction is recycled to the desulfurization step.

Abstract: The invention relates to a hydrometallurgical process for the overall recovery of the components of exhausted lead-acid batteries, in a re-useable form, said components being mainly constituted by such materials as polypropylene, ebanite, PVC; by paste comprising lead sulphatized compounds; and by pure or alloyed metal lead, characterized in that it comprises the following steps:(a) battery crushing,(b) separation of paste by wet-screening,(c) separation of polypropylene by water floating,(d) separation of ebanite and PVC from pure or alloyed metal lead, by means of a first hydrodynamic separation,(e) separation of ebanite from PVC by a second hydrodynamic separation,(f) desulfurization of paste by carbonation by sodium carbonate, with pure sodium sulphate being obtained,(g) recovery of so-obtained pure sodium sulphate,(h) treatment of carbonated paste in order to recovery from it the lead, in pure metal form, by extraction by electrowinning.