Abstract: Silver salts, preferably AgClO.sub.4, AgBF.sub.4, and AgPF.sub.6 are oxidized electrolytically at -15.degree. to +10.degree. C. and a pH between 4.5 and 7.5 with a current density of 40 to 200 A/m.sup.2 to produce pure silver (III) oxide.

Abstract: The invention relates to a process for the recovery of gold from an alkaline aqueous liquid solution containing gold-cyanide ion, and possibly silver and/or copper and/or mercury, which comprises adding a quantity of thiourea to the solution so as to allow formation of a gold complex with thiourea which gold complex is soluble and stable in dilute acid solution, then adjusting the pH of the solution to make the solution mildly acidic, whereby gold and mercury remain in solution in the liquid and silver and/or copper is incorporated in a precipitate containing silver and/or copper cyanide compounds, and then separating the precipitate from the liquid to leave a solution of dissolved gold complex and subsequently recovering the gold from the solution.

Abstract: This is a method for the complete leaching of the valuable metals in a metal sulphide material which contains copper, zinc, lead, silver and iron by the use of a solution which essentially contains cupric chloride/sulphates. After the valuable metals have been recovered, the solution is regenerated whereby ferrous chloride and cuprous chloride/sulphate is oxidized to a ferric hydroxide solid and a cupric chloride solution respectively. The regenerated solution is split into two part-solutions and returned to the process.One part-solution goes to a metathesis stage where the fresh metal sulphide material is added in large excess with respect to the part-solutions's content of copper. The result is that only the valuable metals like zinc, lead and silver are leached while copper and iron remain in the residue.The other part-solution goes to a leach stage where the residue from the metathesis stage is added.

Abstract: A process for the recovery of gold from a precious metal bearing sludge concentrate is disclosed. The process comprises the steps of leaching the sludge with hydrochloric acid and hydrogen peroxide to solubilize at least gold, palladium and platinum, removing silver from the leach slurry as insoluble silver chloride and selectively precipitating gold from the leach solution remaining after removal of silver by reduction with SO.sub.2 in the presence of sodium ions.

Abstract: A method for reclaiming gold in metallic form from gold-containing scrap, including gold-containing base metal alloys and articles in which base metals are at least partially covered with a layer of gold. The method includes the steps of exposing the gold-containing scrap under an inert atmosphere to a leaching solution. The leaching solution has dissolved therein an oxidizing agent including metal ions capable of assuming at least two oxidation states, a portion of the metal ions being in the higher of the two oxidation states. The leaching solution also contains a complexing agent including halide ions in aqueous solution. By so exposing the gold-containing scrap to the leaching solution, base metal contained therein is dissolved to leave a solid metallic residue enriched in gold. The solid metallic residue then is collected mechanically.

Abstract: A process is provided for removing copper from a solution containing same with a chelating agent. The process is advantageously practiced on aqueous effluents from electroless plating systems to remove copper from an aminopolycarboxylic acid chelating agent such as ethylene diaminetetraacetic acid (EDTA). The process comprises contacting an acidic solution containing copper, and optionally ferric iron ions, and the chelating agent with a water insoluble ion exchange resin having a picolylamine or a pyridyl-imidozole functionality, whereby copper is selectively retained by the resin and the chelating agent remains in solution, and then removing the solution from the resin.

Abstract: This invention provides processes for selectively recovering silver and gold values from feed materials containing both precious metals, and comprises leaching the feed material with a hot ferric chloride-acid brine leach solution for a time sufficient to dissolve the silver, but wherein the gold is not dissolved and remains with the solid residue. The silver-containing ferric chloride-acid brine leachate is separated from the solid residue containing the gold. The leach solution is then cooled to precipitate the silver as silver chloride. The solid residue containing the gold is then leached with hypochlorous acid to dissolve the gold, and after separating the solids form the gold-containing hypochlorous acid leach solution, the gold is precipitated by contacting the solution with sulfur dioxide. The silver chloride may be further processed in a fused salt electrolysis step at or above the melting point of silver to produce a substantially pure silver and chlorine gas.

Abstract: The invention relates to a process for the preparation of basic copper carbonate by reacting copper salts with alkali carbonate in aqueous solution at elevated temperatures and with stirring and subsequently isolating the copper carbonate. In this process, a waste solution from copper etching processes which contains hydrochloric acid and sodium chloride, is stirred into a 5 to 15 weight percent solution of alkali carbonate heated to 40.degree. to 70.degree. C., the pH of the solution not being allowed to fall below 6.5, and the precipitated basic copper carbonate is separated from the aqueous solution in a known manner. A light green, basic copper carbonate is obtained, which is free of copper chloride and copper oxide.

Abstract: A process for the hydrometallurgical recovery of precious metal from an ore or concentrate containing at least some arsenopyrite or pyrite.

Abstract: A process for the recovery of precious metals from ore containing the same is disclosed. The process includes the formation of a lixiviant solution including a thiourea compound, urea and potassium lignin sulfonate. The ore is then exposed to this lixiviant solution to extract the precious metals therefrom, and the dissolved precious metals are then recovered from the solution.

Abstract: The invention relates to a process for recovering silver in sulfuric solutions. Its characterizing feature is that the silver solution is contacted with a quantity of zinc sulfide which is at least equal to the stoichiometric quantity and the surface area of which is at least equal to K Ag.sup.2/3 x V, K being a constant, Ag being the silver concentration in the solution expressed in kilograms per cubic meter, and V the volume of the solution in cubic meters, the surface area being expressed in square meters and the value of K being greater than or equal to approximately 10. Application to the recovery of silver in zinc plant residues.

Abstract: A process for the treatment of a complex manganese ore, wherein it comprises the following stages:(a) crushing the ore,(b) subdividing the crushed ore into a first part and a second part,(c) preparing the first pulp from the first part of the crushed ore,(d) reacting the first pulp with a reducing agent to obtain a manganous sulphate solution,(e) separating the liquid phase constituted by the thus obtained manganous sulphate solution from the solid phase of the thus treated first pulp,(f) preparing a second pulp from the second part of the crushed ore,(g) subjecting the second pulp to a solubilization treatment of the nickel, copper and cobalt by reacting it hot with sulphuric acid and the manganous sulphate solution obtained in stage (e),(h) separating the liquid phase and the solid phase of the thus treated second pulp, and(i) recovering the nickel, copper and cobalt from the liquid phase separated in stage (h).

Abstract: A hydrometallurgical process is provided for separating heavy metal nuisance elements such as As, Sb, Bi, Sn and Pb from precious metals and/or selenium. The process can be used as a step in an overall hydrometallurgical process for treating refinery residues such as anode slimes for the separation and recovery of valuable metal values.

Abstract: A process for lixiviation of concentrates of copper sulphides of tetrahedral type containing high concentration of arsenic and antimony to recover copper and noble metals. The concentrates are repulped into an aqueous ferrous sulphate solution with an established and controlled solid-liquid ratio which is thereafter oxidized by an oxygen containing gas in a reactor, thereby oxidizing the sulphides to sulphates, precipitating iron as ferric arsenates and antimoniates and yielding a lixiviation pulp in which the solid phase contains the iron, antimony and arsenic as well as the insoluble sulphates of the non-ferrous metals, such as lead and noble metals, and the liquid phase containing the copper, free sulphuric acid and the soluble sulphates of non-ferrous metals, as well as zinc, cadmium, cobalt, etc. The metals contained therein are recovered, after solid-liquid separation by conventional method.

Abstract: A process for recovering gold from refractory auriferous iron containing sulphidic material which comprises treating an aqueous slurry of the material in a pressure oxidation step at a temperature in the range of from about 135.degree. to about 250.degree. C. under a total pressure of from about 500 to about 5000 kPa to oxidize sulphide sulphur to sulphate form and release gold from a refractory state. The pH of the resultant oxidized slurry is adjusted to a value suitable for cyanidation. The pH adjusted slurry is subjected to a cyanidation step in which gold is dissolved in a cyanide solution. The cyanided slurry is diluted to a pulp density in the range of from about 2 to about 10% solids by weight. The diluted slurry is subjected to a liquid-solids separation step to produce a gold containing solution and a relatively high pulp density gold-containing slurry, and gold from the gold-containing solution and from the high pulp density gold-containing slurry is separately recovered.

Abstract: The invention comprises the treatment of metal oxides and mixed metal oxides and metal sulfides in a vertical tube reactor system having a downcomer section and a riser section in order to oxidize and dissolve the metal values in aqueous slurry primarily in the downcomer section and introducing a reducing agent comprising a formate species and reducing the dissolved metal values in the riser section. The reduced metal values are then separated with the gangue values from the product solution downstream from the vertical tube reactor system. The reduced metal values may then be separated from the gangue material by conventional solid separation techniques, such as flotation.

Abstract: A process for the recovery of gold from refractory auriferous iron-containing sulphidic material which comprises providing an aqueous feed slurry of fresh feed material and oxidized solids from a subsequent pressure oxidation step. The feed slurry has a pulp density in the range of from about 30 to about 60% by weight. The slurry is subjected to pressure oxidation at a temperature of from about 120.degree. to about 250.degree. C. under a total pressure of from about 360 to about 6000 kPa to produce a slurry of oxidized solids. A portion of the oxidized solids is recycled to the feed slurry, and gold is recovered from the remaining oxidized solids.

Abstract: A process is described by which copper and optionally silver and gold are recovered from sulfide and oxide ores, concentrates or slag, which contain the metals. The particulate materials are treated with an aqueous solution of an alkali cyanide or alkaline earth cyanide, the laden solution is filtered, if desired, a water-soluble sulfide compound is added to the laden solution or filtered laden solution, the laden solution is subsequently adjusted to a pH value below 5 by an addition of acid to precipitate the metal sulfide, which is filtered off, and the resulting hydrocyanic acid is recovered. The process steps of precipitation and filtration of the metal sulfide and the recovery of the free hydrocyanic acid contained in the filtrate are carried out under superatmospheric pressure of 1.5 to 15 bars. The precipitation is preferably effected at a pH value of 1.5 to 2.0. The free hydrocyanic acid is recovered as alkali cyanide or alkaline earth cyanide and is recirculated to the leaching stage.

Abstract: A method of recovering copper and nickel from sulphidic minerals containing copper, nickel and iron comprises the steps of roasting the mineral, preferably to provide magnetite; sulphating, for example with sulphuric acid, sulphur trioxide, metal sulphate and/or sulphur dioxide together with oxygen; and a subsequent leaching of the sulphated material and recovery of copper from the leaching solution, for example by electrolysis. All or part of the leaching solution with its nickel content is recycled to the roasting stage, and the nickel content is removed in the form of nickel oxide together with the leaching residue, from which nickel can be recovered.

Abstract: This invention comprises a wet oxidation process utilizing copper (II) oxide as the sole oxygen source. In particular the destruction and detoxification by oxidation of toxic materials such as cyanide, hydrocarbons, halogenated hydrocarbons, and dioxins contained in typically aqueous streams by using copper (II) oxide is contemplated. The preferred embodiment involves adding the copper (II) oxide to the feed stream containing the toxic materials and reacting the stream under elevated pressure and elevated temperature conditions to substantially oxidize the toxic materials to less toxic or innocuous compounds. The oxidation process can be accomplished in a vertical tube reactor system, wherein the necessary pressure for the wet oxidation is achieved by hydrostatic head pressure inherent in the system.

Abstract: A process for separating precious metals from a roaster calcine leach residue from a process wherein copper or zinc sulfides are roasted to produce a copper or zinc calcine; the calcine is leached with an aqueous sulfuric acid leaching solution to produce a copper or zinc-containing leaching solution and a roaster calcine leach residue and the copper or zinc-containing leaching solution is separated from the roaster calcine leach residue wherein the process comprises:(a) intimately contacting the roaster calcine leach residue with an aqueous sulfuric acid leach solution containing from about 5 to about 200 grams per liter of sulfuric acid to produce a slurry of leach solution and roaster calcine leach residue and to dissolve precious metal from roaster calcine leach residue;(b) adding copper or zinc sulfide solids to the mixture of leach solution and said roaster calcine each residue;(c) agitating the copper or zinc sulfide solids in intimate contact with the mixture of leach solution and roaster calcine leac

Abstract: There is disclosed a novel method of recovering valuable metals from an industrial by-product containing copper and arsenic and at least one metal selected from among lead, zinc, iron, silver and cadmium, said method comprising leaching the by-product with sulfuric acid in an SO.sub.2 gas atmosphere at a temperature of 70.degree. C. or higher in the presence of a solid sulfide to thereby precipitate copper selectively as copper sulfide while dissolving other metal or metals in the leach solution and then separating the copper containing precipitate from the leach solution, said leach solution containing substantially no copper.

Abstract: A process for recovering gold from refractory auriferous iron-containing sulphidic ore which comprises feeding ground ore as an aqueous slurry to an acidic pretreatment step. The ground ore in the acidic pretreatment step is treated with aqueous sulphuric acid solution to decompose carbonate and acid consuming gangue compounds, and subjecting the treated slurry to a first liquid-solids separation step to produce a sulphate solution and separated solids. Water is added to the separated solids in a first repulping step to form a slurry having a pulp density in the range of from about 25 to about 60% by weight solids. The first repulped slurry is oxidized in a pressure oxidation step at a temperature in the range of from about 135.degree. to about 250.degree. C.

Abstract: There is described a process for the separation and purification of the platinum group metals from base metal out of acidic aqueous solutions. For this purpose there is used a substituted thiourea of the formulaR.sub.1 R.sub.2 N--CS--NH--CO--R.sub.3orR.sub.1 R.sub.2 N--CS--NH--COOR.sub.3as the precipitation agent. Preferably there are employed N,N-diaklyl-N'-benzoylthiourea wherein R.sub.1 and R.sub.2 are methyl, n-butyl, or n-hexyl.

Abstract: A process for separately recovering platinum group metal values, nickel values and copper from nickel-copper-iron sulphidic matte containing platinum group metals includes leaching ground matte at atmospheric pressure in acidic nickel-copper sulphate solution at a temperature in the range of from about 75.degree. to about 105.degree. C. and at a pH below about 4 initially under oxidizing conditions and subsequently under neutral or non-oxidizing conditions to cause dissolution of nickel and iron, precipitation of copper as a copper sulphide and precipitation of dissolved platinum group metals. The copper, nickel and platinum group metal containing solids are separated from the nickel and iron containing sulphate solution and are leached in acidic nickel-copper sulphate solution under pressurized oxidizing conditions at a temperature of from about 120.degree. to about 180.degree. C. to cause dissolution of nickel and copper with minor dissolution of platinum group metals.

Abstract: A process for recovering gold from refractory auriferous iron-containing concentrate includes feeding the concentrate as an aqueous slurry to an acidic pretreatment step and treating the concentrate in the acidic pretreatment step with aqueous sulphuric acid solution to decompose carbonate and other acid consuming gangue compounds. The treated slurry is oxidized in a pressure oxidation step at a temperature in the range of from about 135.degree. to about 250.degree. C. under a pressurized oxidizing atmosphere while maintaining a free acid concentration of from about 5 to about 40 g/L sulphuric acid to cause dissolution of iron, formation of sulphuric acid and oxidation of substantially all oxidizable sulphide compounds to sulphate form with less than about 20% of oxidized sulphur being present as elemental sulphur during the oxidation step.

Abstract: There is described a process for the separation and purification of the platinum group metals from base metal out of acidic aqueous solutions. For this purpose there is used a substituted thiourea of the formulaR.sub.1 R.sub.2 N--CS--NH--CO--R.sub.3orR.sub.1 R.sub.2 N--CS--NH--COOR.sub.3as the extraction agent. Preferably there are employed N,N-dialkyl-N'-benzoylthiourea wherein R.sub.1 and R.sub.2 are methyl, n-butyl, or n-hexyl.

Abstract: The invention is concerned with a method for the selective dissolution of lead in relation to zinc that is present as a sulphurized compound.The method comprises treating said compound to lixiviation with a solution containing ferrous chloride, while bubbling a gas that contains oxygen through the lixiviating solution.

Abstract: A process for the hydrometallurgical recovery of gold from materials containing gold comprising leaching the materials with a lixiviant containing iodine. To a solution concentrated with natural salts is added elemental iodine until saturated, whereupon mineral sulfides in the ore zone charged with this solution react with the iodine to form iodide. Additional elemental iodine is then added to this iodide-bearing solution until the desired concentration of total iodine and ratio of iodine to iodide are achieved for optimum leaching. The lixiviant is then circulated through the ore zone until all the gold is dissolved. Gold is subsequently recovered on activated charcoal. The excess iodide formed during the process is reoxidized to iodine electrochemically in a special diaphragm cell to regenerate the lixiviant.

Abstract: Cuprous chloride, which is contained in a reduced leach solution or pregnant liquor, can be recovered as a complex salt of alkali metal chloride, such as potassium chloride, or alkaline earth metal chloride or ammonium chloride. The salts are produced by oxidation of a copper ore, such as chalcopyrite, with ferric chloride and cupric chloride, and after removal of insolubles, by adding sufficient metallic copper to the solution to reduce cupric ions to cuprous ions so as to provide a solution containing 1.5 to 2.5 molal potassium chloride, or other metal or ammonium chloride, and cooling the resultant saturated solution to precipitate the potassium chloride-cuprous chloride complex salts and recovering the complex salts. Also provided as a method for recovery of pure copper metal by electrolysis of solutions derived from the complex salts wherein the impurities are diverted to an anode loop which is separated from the cathode loop by a diaphragm.

Abstract: Cuprous chloride, which is contained in a reduced leach solution or pregnant liquor, can be recovered as a complex salt of alkali metal chloride, such as potassium chloride, or alkaline earth metal chloride or ammonium chloride. The salts are produced by oxidation of a copper ore, such as chalcopyrite, with ferric chloride and cupric chloride, and after removal of insolubles, by adding sufficient metallic copper to the solution to reduce cupric ions to cuprous ions so as to provide a solution containing 1.5 to 2.5 molal potassium chloride, or other metal or ammonium chloride, and cooling the resultant saturated solution to precipitate the potassium chloride-cuprous chloride complex salts and recovering the complex salts. Also provided as a method for recovery of pure copper metal by electrolysis of solutions derived from the complex salts wherein the impurities are diverted to an anode loop which is separated from the cathode loop by a diaphragm.

Abstract: The disclosure relates to a process for liquid/liquid-extraction of heavy metal ions from acid aqueous solutions with the aid of water-insoluble dithiophosphoric acid diesters as extracting agents. More particularly, use is made of phosphoric acid solutions with a P.sub.2 O.sub.5 -content of from 3 to 80 weight %, the solutions being free from emulsion-forming organic contaminants or having previously been freed therefrom in known manner. The resulting aqueous phase is separated from the phase containing the dithiophosphoric acid diester.

Abstract: A process is described for removing copper and manganese ions from a saturated aliphatic monocarboxylic acid containing from 6 to 9 carbon atoms by extracting the metal ions into an aqueous layer in the presence of an extractant acid, the hydrogen of which can be replaced by both metal ions. The metal ion-containing aqueous layer may then be separated from the monocarboxylic acid-containing organic layer, with the latter layer having a substantially reduced content of copper and manganese ions.

Abstract: A process and apparatus for extracting gold fines and other precious metals dissolved or suspended in water and not usually visible to the naked eye by circulating a stream of water determined to contain such gold fines and the like downwardly through a tank and into contact with electrostatically charged particles of mercury thereby causing any gold or other precious metals in the water to react with the mercury forming amalgams. The gold and other precious metals may then be separated from the amalgams by any suitable techniques known in the art.

Abstract: A method for producing finely divided stable cupric hydroxide comprising contacting solutions of an alkali metal carbonate or bicarbonate and a copper salt, precipitating a copper carbonate, contacting the precipitate with an alkali metal hydroxide and converting the copper carbonate to cupric hydroxide and re-forming alkali metal carbonate and repeating the sequence of additions of copper salt and alkali hydroxide for up to 20 cycles without addition of any additional alkali metal carbonate or bicarbonate.

Abstract: The invention relates to a process for separating seminoble metals or noble metals from aqueous solutions having compounds of these metals dissolved therein, by reaction with yellow phosphorus. More particularly the aqueous solutions are contacted with carrier material having a yellow phosphorus coating applied thereto.It is possible for the aqueous solutions to be conveyed through a zone having the yellow phosphorus-coated carrier material placed therein, and for them to be subsequently conveyed through a further zone having uncoated carrier material placed therein.

Abstract: A pigment for a color-changing heat indicator comprising a product obtained by interaction of an aqueous solution containing ions of copper and mercury with an aqueous solution of a nitrogen-containing organic compound: an amide of carbonic acid, an amide of thiocarbonic acid, a tertiary amine to give a reaction mixture which is reacted with an aqueous solution containing ions of iodine at an atomic ratio of copper:mercury:iodine equal to 2:1.5:3-5 and an amount of the nitrogen-containing organic compound equal to 0.8-8% of the total content of copper and mercury; the pigment has its critical temperature of from 38.degree. to 70.degree. C. and a heat-resistance of from 160.degree. to 180.degree. C.

Abstract: Dissolved selenium values are removed from an acidic aqueous copper sulphate solution by treating the solution at a temperature of at least about 140.degree. C. with a stoichiometric excess relative to the dissolved selenium of sulphur dioxide or a sulphite solution to produce a selenium-containing precipitate and dissolved cuprous copper. The temperature of the treated solution is maintained at at least about 140.degree. C. and an oxygen containing gas is passed into the treated solution under a pressure of at least about 350 kPa to oxidize dissolved cuprous copper to dissolved cupric copper.

Abstract: Selenium (IV) and selenium (VI) are removed from acidic copper-nickel sulphate solutions in a two-stage process by adjusting and maintaining the sulphuric acid content of the solution in a range of 10 to 50 g/L and, in a first stage, contacting the solution with sulphur dioxide or a sulphite-containing solution at an elevated temperature in the range of about 140.degree. to 175.degree. C. and, in a second stage, maintaining the said solution at an elevated temperature in the range of about 140.degree. to 200.degree. C. and pressure within the range of about 400 to 1750 kPa in an essentially oxygen-free atmosphere for a sufficient retention time to reduce and precipitate selenium (VI) as cuprous selenide.

Abstract: Cuprous chloride is produced from the complex salt, 2KCl.CuCl, obtained as a by-product in the copper industry where chalcopyrite is decomposed in the presence of potassium chloride, by a series of steps involving reaction of an aqueous solution of the complex salt of potassium chloride and cuprous chloride with ammonia, separating the resulting solid potassium chloride from a solution containing cuprous chloride and ammonia, removing the ammonia from the solution to cause precipitation of the cuprous chloride and recovering solid cuprous chloride. Ammonia may then be recycled to the solution from which the cuprous chloride is removed and to which additional complex salt is added to repeat the cycle.

Abstract: A process for removing dissolved selenium IV values from an acidic aqueous copper sulphate solution includes passing the solution through a tubular member in a plug flow manner and injecting sulphur dioxide or a sulphite solution into the solution as it enters the tubular member. When the sulphate solution also contains dissolved selenium (VI) values, the ratio of dissolved selenium (IV) values to dissolved selenium (VI) values is preferably at least 3 to 1.

Abstract: Cuprous (Copper (I)) chloride is an intermediate for the production of copper metal concentrates. A method of purifying copper salts and particularly cuprous chloride is disclosed which involves utilizing the solubility of cuprous chloride and other copper salts in a mixture of water and acetonitrile of 2-hydroxycyanoethane or acrylonitrile and the ability of cuprous chloride to precipitate when the organic component of the mixture is distilled off. The electrolysis of cuprous chloride in water containing at least 10 grams per litre of copper (I), acid and between 5% and 50% by volume of a water soluble organic nitrile such as acetonitrile or 2-hydroxycyanoethane is also disclosed.

Abstract: A process for precipitating iron as a jarosite from a sulphate solution containing ferric iron, free acid and valuable non-ferrous metals, characterized by cooling the solution; partially neutralizing the free acidity, and then clarifying the solution; heating the clarified solution to a temperature not exceeding the boiling point at atmospheric pressure, in the presence of at least one ion selected from the group consisting of sodium, potassium and ammonium ions, and in the presence of recycled jarosite, and without the addition of any further neutralizing agent, so that substantially all of the ferric iron is precipitated as a jarosite; and separating precipitated jarosite from the solution; thereby producing a jarosite contaminated with only minor amounts of non-ferrous metals, and a solution which may be further processed by established procedures for the recovery of dissolved valuable non-ferrous metals therefrom. The invention also contemplates a dilution step, and recycle of jarosite.

Abstract: Silver-precipitating nuclei are prepared by partially oxidizing a stannous salt reducing agent with potassium, sodium or ammonium dichromate and then reducing a noble metal salt or complex with said reducing agent.

Abstract: Silver-precipitating nuclei are prepared by partially oxidizing a stannous salt reducing agent with a ferric oxidizing agent and then reducing a noble metal salt or complex with said reducing agent.

Abstract: A method for manufacturing explosive articles which contain primary explosives and therefore present explosion hazards during conventional loading and packaging operations is disclosed which includes desensitizing the primary explosive such as silver fulminate, for example, by admixing therewith an effective amount of a desensitizing agent to form a resulting composition so as to render the primary explosive insensitive to shock, depositing the desensitized primary explosive on a substrate material, and thereafter, resensitizing the primary explosive by allowing decomposition of the resulting composition to thereby recapture the sensitivity of the primary explosive so deposited.

Abstract: A rapid, energy efficient, low cost, nonhazardous method for the selective removal of mercury from mercury-containing metal cyanide solutions, particularly the cyanide solutions resulting from the cyanidation of gold ore and the like, wherein a reactive sulfide is admixed with the solution for a time sufficient to form an insoluble mercuric sulfide precipitate. The mercuric sulfide precipitate is then separated from the metal cyanide solution by filtration or other conventional means.

Abstract: Copper is removed from spent solutions of complexing agents containing cuprous aluminum tetrahalide, such as CuAlCl.sub.4.toluene by (1) contacting said solutions with water so as to form a precipitate of cuprous halide, an aqueous phase and an organic phase; (2) oxidizing the cuprous halide to cupric halide thereby rendering it water soluble; (3) separating the organic phase and aqueous phase, (4) contacting the aqueous phase with an environmentally suitable metal higher than copper from the electromotive series, such as aluminum, thereby precipitating copper metal and (5) separating the precipitated copper metal from the aqueous salt-containing mixture.Alternatively, the spent complex solutions can be contacted with 1 molar to 6 molar aqueous solution of a non-oxidizing acid such as HCl thereby eliminating the necessity of the oxidizing step (2) since the cuprous halide is soluble in the acidified aqueous phase.

Abstract: A method for thermally decomposing manganese nitrate in an aqueous solution containing alkali and/or alkaline earth nitrates including splashing said aqueous solution containing manganese nitrate to form droplets or sheets of solution, heating said droplets or sheets of solution to partially decompose each droplet or sheet of solution to form manganese dioxide and nitrogen dioxide, and reuniting said droplets or sheets of solution containing manganese dioxide with said aqueous solution containing manganese nitrate; and/or spraying said aqueous solution containing manganese nitrate to form droplets of solution, heating said droplets of solution to fully decompose each droplet to form nonstoichiometric manganese dioxide, and nitrogen dioxide, and recovering said nonstoichiometric manganese dioxide.

Abstract: A process for obtaining pure aluminum oxide (Al.sub.2 O.sub.3) from siliceous aluminum ore is disclosed. The aluminum ore is digested in a hydrochloric acid solution to obtain aluminum chloride, the aluminum chloride is crystallized as the hexahydrate, the aluminum chloride hexahydrate is purified and, subsequently, decomposed to give pure aluminum oxide and secondary products. The mother liquor of the crystallization step and the secondary products of the decomposition step are recycled.