Abstract: A process for upgrading a precious metals-containing concentrate or residue results in near-quantitave removal of base metals and several impurity elements at elevated temperatures. The precious metals-containing concentrate or residue is exposed to oxygen or an oxygen-containing environment in an oxidative pre-treatment step followed by treatment with a hydrochlorinating agent in a hydrochlorination step to form an upgraded concentrate or residue.

Abstract: The invention relates to a method for removing chloride from zinc sulphate solution in conjunction with zinc production. According to the method, the chloride is removed from solution by means of monovalent copper, which is produced in a separate copper(I) oxide formation stage, in which the pH is regulated to the region of 4.5-5.

Abstract: A process for chlorinating ore, slag, mill scale, scrap, dust and other resources containing recoverable metals from the groups 4-6, 8-12, and 14 in the periodic table. The process comprises: a) forming a liquid fused salt melt consisting essentially of aluminum chloride and at least one other metal chloride selected from the group consisting of alkali metal chlorides and alkaline earth metal chlorides, wherein the aluminum chloride content in the liquid salt melt exceeds 10% by weight; b) introducing the recoverable metal resources into said liquid salt melt: c) reacting the aluminum chloride as chlorine donor with said recoverable metal resource to form metal chlorides, which are dissolved in the salt melt; and d) recovering the formed metal chlorides from the salt melt.

Abstract: A process for recovering a metal chloride or mixed metal chloride from a solid waste material comprising recoverable metal containing constituents produced by lead, copper or zinc smelting and refining processes, said process comprising the steps of: (i) heating the solid waste material; (ii) treating the heated material of step (i) with a gaseous chloride to form a gaseous metal chloride containing product; and (iii) treating the gaseous metal chloride containing product of step (ii) to recover the metal chloride or mixed metal chloride. The metal chloride may be further treated to extract the metal itself.

Abstract: A heap leaching method to recover copper from a primary copper sulphide mineral wherein the mineral is leached in an acidic chloride/sulphate solution in the presence of oxygen with the surface potential of the mineral below 600 mV (vs. SHE) to cause dissolution of the copper sulphide.

Abstract: A process for chlorinating ore, slag, mill scale, scrap, dust and other resources containing recoverable metals from the groups 4-6, 8-12, and 14 in the periodic table. The process comprises: a) forming a liquid fused salt melt consisting essentially of aluminum chloride and at least one other metal chloride selected from the group consisting of alkali metal chlorides and alkaline earth metal chlorides, wherein the aluminum chloride content in the liquid salt melt exceeds 10% by weight; b) introducing the recoverable metal resources into said liquid salt melt: c) reacting the aluminum chloride as chlorine donor with said recoverable metal resource to form metal chlorides, which are dissolved in the salt melt; and d) recovering the formed metal chlorides from the salt melt.

Abstract: A hydrometallurgical process for the treatment of complex silver-bearing sulfide ores and concentrates that recovers substantially all silver, lead, antimony, zinc, copper and sulfur, along with the chemical reagents utilized during the process. Finely ground ores and concentrates are leached under heat and pressure with water, sulfuric acid, nitric acid, oxygen, and a catalyst, and are further treated to recover silver in the form of silver chloride; iron in the form of iron hydroxide; copper and all traces of soluble toxic metals as sulfides; zinc as zinc ammonium sulfate and specifically nitric acid, sulfuric acid, oxygen, ammonia, and ammonium compounds as valuable fertilizer products.

Abstract: A method for recovering and reusing a ring-halogenation catalyst comprises: (A) contacting an aromatic compound with chlorine or bromine in the presence of a catalyst composition, where the catalyst composition comprises at least one salt comprising a Group 4-13 metal, a lanthanide metal, or an actinide metal; and at least one organic counterion derived from an organic acid having a pKa relative to water of 0 or greater; and at least one organic sulfur compound; to form a first product mixture comprising a monochloro or a monobromo aromatic compound and a Group 4-13 metal halide, a lanthanide metal halide or an actinide metal halide; (B) separating the metal halide from the first product mixture; and (C) contacting at least a portion of the metal halide and an aromatic compound with chlorine or bromine, and at least one organic sulfur compound; to form a second product mixture comprising a monochloro or a monobromo aromatic compound and a Group 4-13 metal halide, a lanthanide metal halide or an actinide metal

Abstract: The invention relates to a method for recovering gold in connection with the hydrometallurgical production of copper from a waste or intermediate product containing sulphur and iron that is generated in the leaching of the copper raw material. The recovery of both copper and gold occurs in a chloride environment. The gold contained in the waste or intermediate is leached by means of divalent copper, oxygen and alkali bromide in a solution of copper (II) chloride and alkali chloride, in conditions where the oxygen-reduction potential is a maximum of 650 mV and the pH a minimum of 0.5. The bromide accelerates the dissolution of the gold.

Abstract: A chemical process to leach copper concentrates in the presence of a concentrated solution of sulfates and chlorides. The process includes forming a high reactivity chemical paste containing a high concentration of ions in the liquid phase of the paste which react with copper ores and forms a series of soluble salts. The salts are extracted by a simple wash. Mixing equipment for handling high viscosity liquids is used. The total mixing time is about 5 minutes, after which the paste is poured into a rectangular mold, of several hundred meters per side, and is left to settle and breathe. During settling, water and sulfuric acid are added at intervals to replace that consumed by the reactions taking place during the aeration, until the reactions have virtually end. This treatment results in a dry, very resistant mass, containing the copper extracted in form of chlorine salts, and sulfate.

Abstract: A key-operating device includes a shell confining a chamber therein and connected to a video game apparatus with depressible keys, a lever pivotally mounted in the chamber and having protrusions projecting toward the keys, a wheel surrounding and connected to the shell and rotatable relative to the shell, and an actuating member projecting from the wheel and engageable with the lever in such a manner that rotation of the wheel results in engagement between the actuating member and the lever so as to permit fulcrum movement of the lever and pressing of the keys by the protrusions.

Abstract: This invention relates to methods and installations for producing ultra pure sodium chloride salt crystals primarily for use in saturating depleted brine resulting from the electrolytic decomposition of saturated brine in chlor alkali membrane cells for the production of chlorine, caustic soda and hydrogen. More particularly, this invention relates to the production of ultra pure sodium chloride salt crystals by processing primary treated brine by first acidifying the primary treated brine, then stripping the carbonic acid produced by acidification as carbon dioxide, and then returning the brine to a pH of about 6 or higher which is sufficient for processing it in evaporation equipment where the ultra pure salt crystals are produced.

Abstract: The present invention is directed to microemulsion techniques for rapidly preparing photochromic glass nanoparticles and to the photochromic glass nanoparticles so prepared. More particularly, the method of the invention comprises the combination of two microemulsions, one containing a water-soluble silver salt and a glass precursor and the other containing a halide salt and an initiator for glass formation, which process rapidly yields silver halide particles. This invention gives nanometer-sized silver halide particles embedded in glass, thus providing photochromic glass nanoparticles without further annealing, or at most mild annealing. These nanoparticles are valuable as added components to any macro-material that one might wish to have photochromic properties. The particles would impart photochromism while not affecting the physical properties of the material.

Abstract: A method for recovering catalytic metals from compositions containing catalytic metal colloids. Compositions such as rinse solutions or dragout baths containing catalytic metal colloids are passed through a filter that entraps catalytic metal colloids from the solutions. The catalytic metal colloid has a high affinity for the filter in contrast to other components of the solutions. The other components of the solution pass through the filter concentrating the catalytic colloid on the filter. The filter containing the catalytic metal colloid is rinsed with an acid solution to remove the catalytic metal from the filter. The catalytic metal is collected in a suitable container or on an adsorbent such as a resin. The method is economically efficient and environmentally friendly.

Abstract: A method for dissolving noble metals out of segregated ores containing noble metals, comprising: reducing noble metal oxides present to the individual metals in finely divided form; oxidating the segregated ores and/or the noble metals with HCl and chlorate to yield a solution or suspension having a concentration of H+ ions of at least 1 mol/l, a concentration of Cl− ions of at least 1 mol/l and a temperature of at least 50° C.

Abstract: The present invention allows one to use a phase I reactor to make thinner silver halide grains. This is accomplished by introducing the halide salt solution and the silver salt solution as close as possible to each other above the mixer head. The reactor is essentially divided into a micro reaction zone and a bulk reaction zone, thus, emulating the effect of a phase II or two stage reactor.

Abstract: The production of a silver halide emulsion in an aqueous protective colloid solution by the reaction of, on the one hand, silver nitrate, and, on the other, at least one water-soluble halide, may be performed particularly simply and with great apportioning accuracy, if, during at least part of the precipitation, at least the predominant part of one reactant is added in the form of a solid salt to the aqueous protective colloid solution.

Abstract: A method and an apparatus for controlling reactant ion concentration within a precipitation vessel to optimize the reactions occurring therein is disclosed. In one important implementation, the reactant controlled comprises halide ion in a reactor during the precipitation and growth of silver halide grains. In this embodiment, the method includes measuring the amount of halide ion within the precipitation vessel; measuring the flow rates of the halide feed stream and the silver feed stream; storing the measured halide ion concentration and measured feed stream flow rates; computing an estimated smoothed halide ion concentration value as a function of the stored measured halide ion concentration and measured feed stream flow rates; and adjustably controlling the amount of halide ion added to the precipitation vessel as a function of this estimated halide ion concentration value.

Abstract: A method and apparatus for manufacturing silver halide grains wherein a water-soluble silver salt solution and a water-soluble halide solution are separately introduced within a hollow cylindrical structure open at each end which is rotatable mounted about its longitudinal axis within a reaction vessel containing a colloidal aqueous solution. The colloidal aqueous solution within the cylindrical structure is stirred and mixed during the addition of the silver salt solution and halide solution and the silver halide grains which form within the cylindrical structure are immediately discharged into the colloidal aqueous solution between the outer circumference of the cylindrical structure and the reaction vessel through slits in the circumference of the cylindrical structure.

Abstract: A method is disclosed for the quantitative removal and concentration of desired transition metal ions from a source solution which may contain larger concentrations of other metal and H.sup.+ ions. The method comprises bringing the source solution into contact with a compound comprising a pyridine containing ligand covalently bonded through an organic spacer silicon grouping to a solid inorganic support. The pyridine portion(s) of the compound has an affinity for the desired metal ions to form a complex thereby removing the desired metal ions from the source solution. The desired metal ions are removed from the compound by contacting the compound with a much smaller volume of a receiving solution having a greater affinity for the desired metal ions than does the pyridine ligand portion of the compound. The concentrated metal ions thus removed may be recovered by known methods.

Abstract: The present invention is a process to recover precious metals from sulfide ores. It involves chlorinating a mixture of an ore concentrate and salt to form a liquid melt. The salt preferably contains potassium chloride. This chlorination is carried out at a temperature between 300.degree. and 600.degree. C. while stirring. The process converts precious metals in the elemental and sulfide forms into precious metal chlorides which are recovered by subsequent processing steps.

Abstract: Aqueous effluent solutions containing metal cations may be treated with an extractant comprising an organophosphinic acid, a di-2-ethylhexyl phosphoric acid and/or an aliphatic amine to selectively separate chromium, nickel, cobalt, copper and lead cations from the aqueous solution. Typical extraction techniques include liquid-liquid extraction employing either mixer settlers or columns, liquid membrane extraction and selective supported membrane extraction.

Abstract: Carbonaceous ore containing a precious metal (gold) is treated with an aqueous solution of chlorine dioxide to enhance the recovery of the precious metal.

Abstract: Process for recovering gold from a leachate containing AuBr.sub.4.sup.-- comprising contacting the leachate with a quantity of sphagnum peat moss under conditions effective to concentrate the gold on the moss, and thereafter recovering the gold from the sphagnum peat moss.

Abstract: A process and apparatus for the recovery of metals such as silver from phosphate flue dust. The process includes the steps of blending chloride salt and the flue dust to produce a blended material, roasting the blended material in an oxygen bearing atmosphere to oxidize carbon in the blended material producing a gas and to react chloride salt with the metal in the blended material producing a water soluble metallic salt, dissolving the metallic salt in water to produce a solution, filtering the solution to remove solids, and precipitating metals from the filtered solution with the precipitate ready for conventional smelting. The preferred embodiment of the apparatus includes a flue dust hopper and mill and a salt hopper and mill for feeding the dust and salt to a radiant tube dryer and a radiant tube asher for blending and roasting the materials, and a spray chamber at the outlet of the asher for separating solids and gases, where certain of the solids go into solution.

Abstract: The present invention relates to an aqueous ferric chloride leach process for the extraction of metal values from a metal-sulphide bearing material, the leach being carried out in the presence of a leaching aid chosen from among salts of diesters of sulphodicarboxylic acids. It, in particular, relates to the enhanced recovery of metal values from complex, metal-sulphide bearing materials such as, for example, fine grained, polymetallic sulphide ores, their concentrates or the like.

Abstract: Nickel is separated from copper contained in predominantly nickel- and copper-bearing sulphidic matte and alloys by chlorine leaching in an autoclave at over-atmospheric pressure. The leaching is conducted in an acidic solution at a redox potential range which favors the dissolution of nickel over copper. The obtained leach solution is purified in a cementation step carried out at atmospheric or over-atmospheric pressure by adding more sulphidic matte or alloy particles. The separated purified solution is treated for nickel recovery. Any cobalt present in the sulphidic matte or alloy reports with the nickel. Copper is recovered from the separated residue, which will also retain precious metals, if present.

Abstract: A hydrometallurgical process for enrichment of gold, platinum and palladium from copper electrolysis anode sludge, and simultaneously recovery of selenium, in which the sludge is treated with Cl.sub.2 /HCl to transform the selenium of a hexavelent state and precipitate out silver chloride. The filtrate is then subjected to selective reduction of precipitate the noble metals and the resulting filtrate is chlorinated and a further reduction is effected to precipitate the metallic selenium.

Abstract: An improved process for recovering gold from gold-containing materials by iodide/iodine leaching is provided wherein the pregnant lixiviant containing solubilized gold and iodine is treated in an electrolytic cell to reduce gold in solution to elemental gold for recovery and reduce iodine to iodide at the cathode, so as to prevent iodine from interfering with subsequent gold recovery processes, and at the same time reoxidize iodide present at the anode to elemental iodine to regenerate the leach solution to the desired iodide:iodine weight ratio, e.g. about 2:1 to about 10:1. Gold is precipitated in the cathode compartment, and if desired, the cathode effluent may be treated for further removal of traces of gold before being passed to the anode compartment. A method for preventing iron contamination of the cathode is also provided comprising buffering the lixiviant solution to a pH of about 5.

Abstract: Waste containing sulfur and nickel sulfide is heated to volatilize sulfur and reacted with hydrogen chloride to form nickel chloride.

Abstract: A gold recovery process is disclosed in which the gold content of ores, including carbonaceous ores or mixtures of carbonaceous and oxide ores, is extracted by a simultaneous chlorine leach and ion exchange resin adsorption procedure. The process eliminates or reduces the degree of oxygenation and cyanidation required to conduct a standard gold extraction process.

Abstract: Gold sand resulting from the nitric acid treatment of silver refinery slimes is purified by washing with hydrochloric acid under controlled operating conditions. Platinum and other precious metals and impurities are selectively separated from the gold sand leaving a gold sand which is more efficiently refined.

Abstract: A process is provided for reducing the total concentration of heavy metals, notably lead, copper and zinc, naturally occurring in silica-rich sludge precipitated from geothermal brine in a brine handling system such as a geothermal brine electric generating plant. The process includes washing the sludge with hot water to displace any brine entrapped in the sludge, dewatering the washed sludge and leaching the silicious solids residue with hydrochloric acid having a concentration of between about 2 and about 9 weight percent and an acid-to-sludge weight ratio between about 0.10 and about 0.33. The acid-sludge mixture is heated to a temperature of at least about 50.degree. and the leaching time is at least about one hour. The leaching solution is separated from the leached sludge and the solids residue are washed with water. Preferably the water used in both washing steps is condensate of steam derived from the geothermal brine. Effluent from the process is preferably combined with the brine for reinjection.

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 hydrometallurgical process for recovering pure silver from sludge formed at the anode in copper electrolysis and other sources comprises suspending the sludge, after removing Pb, Ni, and Cu, in hydrochloric acid, subsequently adding an alkali metal hypochlorite, preferably NaOCl, to the resulting suspension to convert the silver present to AgCl, filtering to separate the AgCl containing solid residue from the filtrate containing the other metallic elements, and finally working up the AgCl containing residue to obtain high purity silver. Preferably the high purity silver is obtained from the AgCl containing residue by leaching with an alkaline ammoniacal solution to dissolve the silver as the soluble silver diamine chloride, and subsequently reducing the silver diamine chloride to silver metal. The reducing agent for the silver diamine chloride is preferably either a Cu.sup.+ containing compound such as CuCl or a metal powder such as copper or bronze powder.

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: Metal values are separated from arsenic sulfide ores in a hydrometallurgical oxidation process using a balanced reactant slurry. The molar concentration of As and Sb in the reactant slurry is controlled with respect to the molar concentration of Cu, Pb, and Zn in the slurry so that, upon reacting, soluble arsenic compounds or toxic arsenic vapors are not formed.

Abstract: A process and apparatus is disclosed for the chlorinating volatilization of impurity metals detrimental to the production of iron from a raw material which contains the oxides of the impurity metals and iron or which forms them in an oxidizing atmosphere, in which the pulverous raw material is at a high temperature of 900.degree. C. or more and in an oxidizing atmosphere contacted with a magnesium chloride in order to chlorinate and volatilize the impurity metals. The preheated raw material and anhydrous magnesium chloride are fed into a fluidized bed on an inclined grate, hot air being fed into the bed through the grate in order to volatilize the chlorides of the impurity metals, and purified raw material is discharged from the lower section of the fluidized bed into a separate chamber, in which it is rinsed with an air flow the flow rate of which is substantially higher than that of the air flow fed into the fluidized bed.

Abstract: A process is disclosed for the hydrometallurgical treatment of finely divided iron-containing steel plant dusts containing zinc, lead and such other metal values as calcium, manganese, silicon, magnesium, aluminum, cadmium, copper, and the like. The process is carried out by forming an aqueous slurry of the flue dust with a mixed lixiviant comprising HCl and H.sub.2 SO.sub.4, the amount of sulfate ion concentration being in excess of the chloride ion concentration and in stoichiometric excess of that required to sulfate substantially all of the lead and calcium present. The amount of chloride ion present as HCl should be sufficient to maintain the pH at about 1 to 4. The leaching is conducted at a temperature ranging from ambient to below the boiling point for a time at least sufficient to effect dissolution of at least zinc and other metal values and form a residue containing iron oxide, calcium sulfate and lead sulfate.

Abstract: The invention relates to an improvement in a method for recovering metal values from copper-containing and/or precious-metal containing materials which also contain antimony and/or bismuth in such high quantities as to render working-up of the materials with conventional metallurgical processes difficult or impossible. In accordance with the improvement, the material is subjected to a chlorination volatilization process in a manner to bring the antimony and/or bismuth content of the material to a predetermined low level acceptable for the continued working-up of the material in conventional process stages, while maintaining the metal values of the material in a substantially unaffected form. The volatilization process is best carried out at temperatures of between 450.degree. C. and 750.degree. C., preferably between 550.degree. C. and 650.degree. C.

Abstract: This invention relates to a process for making the chloride of a metal from the sulfide of said metal in the absence of air and for a metal selected from copper, iron, lead, zinc, silver and gold. The process consists of three broad steps. First, forming an intimate mixture of finely divided sulfides of the metals with finely divided chlorides, the latter being in an anhydrous state. Second, heating the mixture to a temperature at which there is a rapid reaction converting the metal sulfides to chlorides and elemental sulfur in the state of a solid aggregate mixture. Third, recovering the formed metal chlorides from the aggregate mixture by conventional means.

Abstract: In the hydrometallurgical treatment of metal-bearing ores and particularly the beneficiation of iron-containing titaniferous ores wherein the ore is subjected to leaching with a dilute aqueous acid solution in a digestion zone, there is provided an improvement which comprises initiating and maintaining the mixture of ore and acid in a state of boiling. Initiation and maintenance of the mixture in a state of boiling is accomplished through the venting of the digestion zone to remove process vapors substantially in the form of water vapor. Initiation of the boiling of the mixture of ore and acid solution in the digestion zone is commenced when the temperature of the mixture and consumption of the free acid solution in said mixture have reached predetermined values. The initiation and maintenance of the mixture in a state of boiling results in an increased rate of dissolution of the contaminant values in the metal-bearing ore.

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: Copper content in sulphide-containing materials such as ores or concentrates is extracted by leaching the material by means of a leaching solution containing iron (III) chloride and copper (II) chloride, the leaching process being regulated in order to keep the red-ox potential in the leach solution between 430 mV and 460 mV, whereby iron (III) chloride is reduced to iron (II) chloride while copper (II) chloride is kept in the bivalent state. The copper content in the ore or concentrate is thereby leached as copper (II) chloride. Copper (II) chloride is thereafter extracted from the pregnant leach solution by contacting the solution with an organic complex-ion forming extractant which extraction properties are dependent on the chloride concentration.

Abstract: The selective leaching of metal ions from various iron oxide and manganese oxide containing ores employs intermediary solutions. The leaching processes are based upon a redox acid leach step employing stabilized cuprous ions and, in one instance, a combination thereof with ferrous ions. Leaching is conducted at low temperatures, up to about 90.degree. C. and low pressures, up to about 1.5 MPa and at a pH of about 1.5 to 2.5. Nickel and cobalt recoveries from the ores, employing these processes, will usually equal or exceed 90 percent. The intermediary solutions comprise stabilized acidic cuprous ions Cu.sup.+ L wherein L is a stabilizing ligand selected from the group consisting of CO, XRCN and Cl.sup.-, X being --H or --OH and R being aliphatic having from one to about four carbon atoms. In at least one process, ferrous ions are introduced for a separate leaching step.

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: The invention relates to a process for the continuous preparation of photographic emulsions by a continuous flow process, in which a volume stream entering a pipe system flows successively through the various sections of this system corresponding to the individual stages of the process, such as the inlet points for introduction of the volume streams, mixing paths and ripening paths.

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.