Abstract: Provided is a method for separating copper from nickel and cobalt, which is capable of efficiently and selectively separating copper, and nickel and cobalt from an alloy containing copper, nickel and cobalt such as a highly anticorrosive alloy that is obtained by subjecting a waste lithium ion battery to a dry treatment and contains copper, nickel and cobalt. According to the present invention, an alloy containing copper, nickel and cobalt is brought into contact with an acid in the coexistence of a sulfurization agent, thereby obtaining a solid that contains copper and a leachate that contains nickel and cobalt.

Abstract: A method for selectively precipitating basic zinc carbonates (BZC) from basic copper carbonates (BCC) from an aqueous ammoniacal solution prepared using a mixture of copper- and zinc-containing materials.

Abstract: A process for producing basic lead carbonate is provided. The process comprises: (1) immersing neutralization slag to obtain sodium hydroxide solution; (2) leaching lead chloride slag with the aqueous solution containing sodium chloride and hydrochloric acid, adding sodium sulfide and filtering; (3) neutralizing the filtrate with sodium hydroxide solution, filtering and washing the precipitate; and (4) converting the precipitate to basic lead carbonate with ammonium bicarbonate, crystallizing and washing. Said neutralization slag and lead chloride slag are the redundant slag from fire refining bismuth. Said process makes better use of the redundant slag from fire refining bismuth, saves resources and reduces environmental pollution.

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: Methods and systems for heavy metal separation and recovery from heavy metal-containing sludge or wastes. The method utilizes ultrasonic treatment assisted acid leaching process to separate and recover different heavy metals from multi metals-containing sludge. The technique can be cost effectively implemented for heavy metal separation and purification processes in the real world at industrial scales.

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 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 zinc ions by selective zinc sulfide precipitation from an aqueous solution comprising zinc ions and metal ions of a metal that precipitates as a metal sulfide at a pH lower than a pH at which zinc ions precipitate as a zinc sulfide.

Abstract: A method for processing waste copper liquid produces high copper content sludge, mainly by recycling a low copper content waste liquid from production of PCB in order to discharge a comparatively higher copper content sludge. First, the waste liquid is classified into an acidic low concentration copper waste liquid, an acidic high concentration copper waste liquid, and an oxidized acidic high concentration copper waste liquid. Then mix with a strong alkali to react and form a cupric oxide sludge that then undergoes dehydration and baking by applicable equipment to remove water and get a higher copper content sludge. It is therefore unnecessary to add other conversion agents to convert copper hydroxide into cupric oxide, thereby turning the valueless low copper content sludge from a waste liquid into a valuable recyclable high copper content sludge.

Abstract: The invention relates to a method for the treatment of material containing at least one valuable metal and arsenic to form a valuable metal-depleted scorodite sediment and a pure aqueous solution to be discharged from the process. According to the method, the valuable metals are first removed from the material to be treated and then arsenic precipitation from the solution is performed in two stages. By means of the method, the aim is to obtain as low a valuable metal content as possible in the scorodite sediment that will be formed. Likewise, the arsenic and valuable metal content of the aqueous solution that is formed during arsenic precipitation also remains so low that the water can be released into the environment.

Abstract: A method for treating a polymetallic sulfide ore containing gold and/or silver, and further containing base metals selected from the group consisting of iron, aluminum, chromium, titanium, copper, zinc, lead, nickel, cobalt, mercury, tin, and mixtures thereof, is disclosed. The method comprises the steps of grinding the polymetallic sulfide ore to produce granules, oxidizing the granules to produce oxidized granules, and chloride leaching the granules using a brine solution including dissolved halogens, as well as chloride and bromide salts.

Abstract: The present invention discloses a method for processing waste copper solution/liquid to produce high copper content sludge, mainly by recycling a low copper content waste solution from production of PCB in order to discharge a comparatively higher copper content sludge; first classify the waste solution into an acidic low concentration copper waste solution, an acidic high concentration copper waste solution, and an oxidized acidic high concentration copper waste liquid, and then mix with a strong alkali to react and form a cupric oxide sludge, then undergo dehydration/baking by an applicable equipment to remove water and get a comparatively higher copper content sludge; therefore, it is unnecessary to add other conversion agents to convert copper hydroxide into cupric oxide, thereby turning the valueless low copper content sludge from a waste water (or liquid) into a valuable recyclable high copper content sludge.

Abstract: A method for recovering zinc ions by selective zinc sulfide precipitation from an aqueous solution comprising zinc ions and metal ions of a metal that precipitates as a metal sulfide at a pH lower than a pH at which zinc ions precipitate as a zinc sulfide.

Abstract: This disclosure relates to a family of micronutrient supplements that can be used in food or in animal feeds and to methods of enhancing the growth of animals using one or more of the supplements. The family of micronutrient supplements is an ammine chloride salt of an essential metal. Representative essential metals for use according to this disclosure include a divalent or trivalent cation of zinc, copper, manganese, magnesium, chrome, iron, cobalt and calcium. When provided as a metal ammine chloride salt, the essential metal is highly bioavailable to enhance the survivability, growth, health and/or reproductivity of animals. The micronutrient supplement can be administered to animals either as a single supplement or admixed with other nutrients or feeds.

Abstract: The present invention generally relates to a copper metal recovery system, able to integrate with a waste treatment system of a circuit board manufacture plant, includes a stirring unit, a crystallization unit and a pressure filtering unit. More than 2 parts of weight of acidic copper-containing etching process effluent, less than 1 parts of weight of copper-containing slurry, and less than 1 part of weight of waste mixture of an acidic copper-containing photolithography effluent and an acidic frame etching effluent are charged into the stirring unit to conduct decomposition. Alkaline hydroxide reacts with decomposition products in the crystallization unit. The temperature of the crystallization unit is at least 80° C. The pressure filtering unit outputs a copper hydroxide solution or a copper oxide solution.

Abstract: A silver oxide powder that replaces silver powder as a silver conductive paste filler has a specific surface area measured by the BET method is 1.0–25.0 m2/g, average primary particle diameter is 1–50 nm, and average secondary particle diameter is 1–1000 nm. The silver oxide powder is made by preparing a neutralization medium that is an aqueous solution containing one or both of sodium hydroxide and potassium hydroxide in a total amount of 0.5 mole/L or less, simultaneously adding an aqueous solution containing silver salt in an amount of 6.0 mole/L or less and an aqueous solution of at least one of sodium hydroxide and potassium hydroxide to the liquid medium to conduct a neutralization reaction, thereby obtaining a neutralized precipitate, maintaining the liquid at a pH in the range of 12±1.5 during the reaction, and subjecting the precipitate to filtration, washing, and drying.

Abstract: A method for recycling copper oxide includes: a first step in which a sodium hydroxide aqueous solution is added to acidic copper chloride waste etchant produced in the PCB industry, to obtain copper hydroxide slurry; and a second step in which the slurry obtained in the first step is heated and sintered to thereby prepare a needle-form copper oxide. Since copper oxide has a purity of more than 99.0 wt % and the needle-form crystal morphology, so that it has an excellent filtering ability and homogeneous particle size distribution.

Abstract: Stable copper hydroxide is prepared by removing ferrous ion from the beginning cupric solution. The ferrous ion is oxidized to ferric ion, and the ferric ion is precipitated by raising the pH of the solution to 3-4. The utilization of phosphate ion both increases the efficiency of oxidation and simultaneously precipitates ferric ion. A second raising the pH of the purified solution precipitates highly pure copper hydroxide that can be harvested.

Abstract: Ozone is used to rapidly oxidize specific metallic elements. The insoluble oxidized compounds of the metals formed by the ozonation are then recovered for industrial use in a conventional sedimentation/filtration tank or pool. There is no requirement for pre-treating or neutralizing the acid mine discharge, even when iron is the dominant metal. If the pH of the untreated acid mine discharge is less than about 2.5, metals other than iron precipitated first. After that, the pH is raised and the iron is precipitated as ferric hydroxide. Aluminum is removed as hydrated aluminum compounds after removal of the iron prior to discharging the acid mine discharge to streams. Both the ozonation and neutralization processes are monitored and controlled using electrochemical sensors and feedback controllers.

Abstract: A process for separating a first source of a heavy metal ion or mixtures of heavy metal ions, (Me1), from a solution comprising a complex of said Me1 and EDDS, (Me1-EDDS), by displacement of said Me1 with a second source of a heavy metal ion Me2 by addition to the solution of a salt of said Me2.

Abstract: A method for producing zinc diammine chloride (ZDC) from a solution of zinc ammine sulfate and zinc ammine chloride by precipitating the ZDC by pH neutralization using hydrochloric acid. ZDC can be granulated for dry applications using melt granulation at about 340-360° F. Applications for ZDC include use in fertilizer formulation to provide a combination zinc/nitrogen source free of other metals and use as a galvanizing preflux adjuster. As a galvanizing preflux adjuster, ZDC addition is able to adjust the pH of the preflux while maintaining the desired zinc/ammonia ratio.

Abstract: A method of recovering precious metals from metal alloys produced aluminothermically from base metal smelter slag, includes treating the metal alloy with aqueous sulphuric acid solution having a pH of not greater than about 2 to cause dissolution of nickel and/or cobalt and iron and to cause formation of hydrogen sulfide which reacts with copper in the metal alloy to form a copper sulfide precipitate containing at least one precious metal, and separating the copper sulphide precipitate containing at least one precious metal from the remaining solution containing cobalt sulphate and/or nickel sulphate and ferrous sulphate.

Abstract: A method for the total precipitation of valuable metals, such as copper, nickel, zinc, cobalt, etc., from a leaching solution that has been acidified with sulphuric acid and that is substantially free from impurities, by neutralizing the solution with lime and/or limestone. Neutralization is effected in at least two stages, wherewith only partial precipitation is effected in the first stage, and wherewith full precipitation of remaining valuable metal content is effected in the last stage, by adding a surplus of neutralization agent. Slurry containing precipitates and remaining solid neutralization agent formed in the last stage in the neutralization process is returned to the first neutralization stage, possibly after re-dissolving the slurry in the incoming acid leaching solution. The amount of slurry returned together with any further neutralizing agent added promotes the partial precipitation of the valuable metal content.

Abstract: This invention relates to synthetic chalcoalumite-type compounds represented by formula (1) below:M.sup.2+.sub.a-x/2 Li.sub.x.sup.1+ Al.sub.4.sup.3+ (OH).sub.b (A.sup.n-).sub.c.mH.sub.2 O (1)(whereinM.sup.2+ represents at least one of the following divalent metal ions: Zn.sup.2+, Cu.sup.2+, Ni.sup.2+ and Mg.sup.2+,a is 0.6<a<1.2,x is 0<x<1.4,b is 11<b<13,A.sup.n- is at least one member of the group consisting of SO.sub.4.sup.2-, HPO.sub.4.sup.2-, CO.sub.3.sup.2-, SiO.sub.3.sup.2-, SO.sub.3.sup.2-, HPO.sub.3.sup.2-, H.sub.2 PO.sub.4.sup.-, NO.sub.3.sup.- and OH.sup.-,c is 0.5<c<1.2, andm represents a number of 1 to 4)and processes for their preparation. The synthetic chalcoalumite-type compounds of the present invention are conveniently used for adsorbing agents of acidic substances, anion exchangers, infrared absorption agents for agricultural films, deodorants and recording media for ink jet, etc.

Abstract: There is provided a method for removing silver from photoprocessing solutions containing hardening agents which comprises:a) adding a chelating agent to the photoprocessing solution in an amount sufficient to inhibit the precipitation of the high valent cations of the hardening agents;b) adding a base to adjust the pH of the photoprocessing solution to a value above 5.5; andc) adding a chemical precipitant for the silver contained in the photoprocessing solution;and optionally adding as a final component a flocculating agent which causes the precipitate to grow in size.

Abstract: A method for stably producing a copper powder having a low degree of oxidation comprises generating copper hydroxide by adding an alkali to an aqueous solution containing copper ions, and reducing the copper hydroxide to obtain copper powder as a precipitate by adding hydrazine or a hydrazine compound to the aqueous solution until the aqueous solution yield a pH value in a range of from about 7 to 9.

Abstract: A process for extracting iron, copper, and nickel from a solution containing iron, copper, nickel, and at least one contaminent selected from the group comprising magnesium, aluminum, calcium and sodium, wherein each of said solutes is present at its respective chloride. In the process, calcium oxide or calcium hydroxide are added as a precipitating agent in incremental steps to cause incremental increases in the pH of the solution. At each increasing pH, one of the aforesaid metals will precipitate as the corresponding metal hydroxide while leaving the remaining metals in solution. The metal hydroxide precipitate is separated from the remaining solution prior to the subsequent addition of the precipitating agent.

Abstract: A process for selectively recovering dissolved heavy metals from a solution is disclosed that involves selectively reacting a xanthate with such dissolved heavy metals. Selective reaction of a xanthate with selected dissolved heavy metals is accomplished by conducting the reaction under conditions such that only some of the heavy metals react with the xanthate, to the exclusion of reaction with other dissolved heavy metals. Selectivity of the reaction is particularly influenced by the pH at which the reaction occurs. Typically, the reaction should occur at a pH below about 4.0. Xanthates, once reacted, can be separated from the heavy metal xanthate reaction product and recycled for use within the process. Purified heavy metal product can be produced if desired.

Abstract: There is disclosed a method of treating a solution, e.g., an alkaline or acidic solution, containing heavy metals ions therein. With respect to alkaline solutions, the method includes providing a body of the solution; contacting the body with a material such as carbon dioxide to change the pH, e.g., to lower the pH to a pH in the range of 9 to 10.5; then treating the solution to further change the pH and cause precipitation of hydroxides, including chromium hydroxide; and separating the hydroxide precipitates from the solution to provide a substantially neutral solution having a reduced amount of chromium ions, for example, contained therein.

Abstract: In the process of removing heavy metals from aqueous solutions by precipitation of a salt thereof at increased pH, multiple stage precipitation by upward stepwise pH adjustment and solid separation at each stage is used to facilitate the manufacture of a product of high purity.

Abstract: Process for the recovery of copper from copper-containing industrial waste waters, in which the ionogenic copper or the copper in complex form is firstly reduced with sugar, then with dithionite, and is separated in metallic form.

Abstract: According to the method of the invention, at least one or several of the metals nickel, cobalt and copper can be selectively precipitated as sulphide by aid of elemental sulphur from aqueous solutions containing other metals such as zinc. The temperature of the reaction is above the melting point of sulphur. The precipitation is carried out with a pH value below 2. The metals to be precipitated can be present in the solution either as oxides or sulphates. If the metals are sulphates, the sulphide of at least one of the metals is prepared to crystal seeds in the solution before precipitation.

Abstract: A method of precipitating metals from a spent geothermal brine containing the same comprises admixing the geothermal brine with a condensate of steam, derived from the brine, in a volume ratio of brine to condensate of 1:2 to 1:10. The invention is particularly applicable to geothermal brine processes for the production of electric power, such as are practiced at the Salton Sea.

Abstract: A method for producing copper sulfate from waste copper-containing liquid including the steps of recovery of acidic and basic copper-containing liquid, and neutralization of the liquid to form crystalline copper sulfate, wherein the ratio of acidic to basic copper-containing liquid, temperature, pH value and the concentration of copper ion in the resultant solution of each step is being controlled such that the solid copper sulfate is obtained in high yield and purity and will have a larger particle size, and at the same time, the filtrate will contain copper ion in a concentration below 0.3 ppm before being expelled to the surroundings.

Abstract: A process for the heavy-metal decontamination of contaminated substances such as natural and industrial sludges, thermal residues and soils. The contaminated starting substance is treated with an acid and the dissolved metal salts are precipitated as metal hydroxides in the pH range of about 3.5-11. The exact control of the pH value makes it possible to isolate individual metal fractions which can be used as raw materials in the metallurgical industry.

Abstract: Copper arsenate, substantially free from impurities that form sludge in wood preservatives such as chromated copper arsenate, is prepared by adding a solution of soluble arsenate to copper sulfate solution, either or both solutions containing sludge-forming impurities, to form a copper and arsenic-containing solution without precipitating copper arsenate. The pH during the adding is controlled at a value in the range of 1.8 to 2.2 to precipitate impurities. Precipitated impurities are removed, and the copper and arsenic-containing solution is neutralized with a suitable alkaline substance to pH 3.5 to 5.0 to precipitate copper arsenate. Arsenate solution is derived from arsenic oxides, soluble arsenic salts and compounds and metallurgical materials capable of yielding water-soluble arsenate. Copper sulfate solution is derived from crystals and compounds and metallurgical materials cable of yielding copper sulfate.

Abstract: A method for removing iron(III), copper(II), zinc(I) and nickel(II) from an effluent containing chelant (EDTA, DEPA, HOEDTA) comprising treating the effluent with a soluble calcium compound (e.g., Ca(OH).sub.2) CaCl.sub.2, Ca(NO.sub.3).sub.2) in a molar equivalent to the chelant in combination with a monovalent hydroxide to a pH greater than 12.4 and then adding an effective amount of a dialkyldithiocarbamate (e.g.; sodium-N,N-diethyldithiocarbamate) to precipitate the metal hydroxides and nickel dialkyldithiocarbamate. Heating the solution to about 180 F. further speeds up the removal of the nickel(II). The nickel concentration of spent chelant cleaning solution can be reduced to less than 1 ppm.

Abstract: Copper arsenate, substantially free from impurities that will form a sludge in the process for producing wood preservatives such as chromated copper aresenate and having a water content of less than 15%, is prepared by mixing a solution of soluble arsenate and a copper sulfate solution, either or both solutions containing sludge-forming impurities, to form a copper and arsenic-containing solution without precipitating copper arsenate. The pH during the adding is controlled at a value in the range of 1.7 to 2.2 to precipitate impurities. Precipitated impurities are removed, and the copper and arsenic-containing solution is neutralized with a suitable alkaline substance, preferably dilute sodium hydroxide solution, to pH 3.2 to 4.2 to precipitate copper arsenate.

Abstract: A method of processing an aqueous feed liquid to precipitate at least one metal (e.g., copper, nickel or a combination thereof) in a form to make the metal subsequently removable from the feed liquid by filtration, comprises the initial step of mixing (i) an aqueous feed liquid containing a soluble salt of the metal to be removed, (ii) oxalic acid in excess of that required to react with metal, and (iii) a pH-adjusting liquid in a quantity sufficient to lower the pH of the feed liquid to a point between that at which the feed liquid becomes slightly supersaturated with respect to the oxalate of the metal and that at which precipitation of the metal oxalate is initiated. The mixture is then allowed to stand (either at room temperature or heated to elevated temperatures) for a period of time sufficient to form metal oxalate, and finally the formed metal oxalate is separated from the feed liquid to leave an aqueous liquid suitable for discharge to a sewer line.

Abstract: Precipitation (conversion) of dissolved heavy metals in waste effluents is achieved with the addition and mixing of a solution of sodium polythiocarbonate with a solution containing dissolved heavy metals. The solution of sodium polythiocarbonate has been pH buffered to a pH of 12.5 or less in the manufacturing process. Precipitation of the dissolved heavy metals with the buffered sodium polythiocarbonate is complete by the formation of a stable, unleachable [as defined in 40 CFR 190.01, Part 261 Appendix II (Code of Federal Regulations)], extremely insoluble metallic polythiocarbonate particle.

Abstract: A process is provided for working up dusts which have been precipitated electrostatically from the gas mixture composed essentially of carbon monoxide and phosphorus vapor produced in the electrothermal production of yellow phosphorus, which process comprises converting the dusts into a calcinate at 300.degree. to 800.degree. C. under oxidizing conditions in a first step, leaching the calcinate with phosphoric acid in a second step, adjusting the pH of the solution in phosphoric acid to 0 to 1.5 with sodium hydroxide solution in a third step, precipitating the sulfides of lead, copper and cadmium from the partially neutralized solution in phosphoric acid by adding sulfide and filtering them off in a fourth step, adjusting the pH of the filtered, partially neutralized solution in phosphoric acid to about 1.5 to 5.

Abstract: Disclosed are processes and an apparatus for refining gold. One of the processes comprises dissolving unrefined gold by use of iodine and/or an iodide compound to form a solution containing an iodide compound of gold, removing insoluble substances in the solution, reducing the ions containing the gold by use of an alkali to precipitate the gold of high purity. In this process, the iodine may be obtained by electrolyzing the iodide compound. The other process and the apparatus further comprise circulating the solution having been separated from the precipitated gold for reuse, and the alkali simultaneously produced by the above electrolysis is economically employed therein.

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 method for producing finely divided stable cupric hydroxide composition of low bulk density comprising contacting solutions of an alkali metal carbonate or bicarbonate and a copper salt, precipitating a basic copper carbonate--basic copper sulfate to a minimum pH in the range of greater than 5 to about 6, contacting the precipitate with an alkali metal hydroxide and converting basic copper sulfate to cupric hydroxide, within the pH range of 7 to 11.

Abstract: A method is provided for recovering gold and silver from precious metal bearing materials including ores, leaching residues, flue dust, electronic scrap, jewelry scrap, etc. In the method, the gold and silver are extracted from the precious metal bearing materials with a thiourea solution to form a thiourea leach, and the thiourea leach is contacted with carbon to adsorb the gold and silver and provide loaded carbon. The method is characterized by the step of contacting an alkaline solution of thiousulfate ion with the loaded carbon thereby desorbing the precious metals form the carbon. In one modification of the method, an additional step includes adding a salt to the aqueous thiousulfate solution. When needed, the method includes the step of protecting the thiousulfate ion from oxidizing agents. This is done by adding a reducing agent such as sodium sulfite to the thiousulfate solution.

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: Process for treating oxidized ores with a manganiferous matrix to recover the small quantities of copper, nickel and cobalt, which consists of attacking the aforementioned ore by means of an aqueous solution of H.sub.2 SO.sub.4 with the simultaneous injection of sulfur dioxide, at a temperature which does not exceed boiling point of the medium, at a pH less than 1.5; introducing an alkaline sulfide to precipitate the copper, nickel and cobalt sulfides in the suspension resulting from the attack; and separating by sulfides and the residue by flotation. The process is applicable to attacks on manganiferous nodules obtained from ocean beds as well as to attacks on land manganiferous matrix oxidized ores.

Abstract: An annular groove formed on the inner surface of the porous sheet of an acoustical aircraft or jet engine liner spaced from the front edge and adjacent to the adhesive bonding material serves to prevent dislodgement of the entire porous sheet upon an impending peeling of the porous sheet. The groove also serves as a circuitous path for cracks propagating upstream from a fault manifested downstream therefrom.

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: A process for recovering copper and copper oxide for spent ammoniacal etchant, electroless and copper persulfate bath fluids used in the manufacture of copper printed wiring boards such that the treated baths contain no ammonia. The spent solutions are placed in a cooking vessel having its inner surface made of titanium and the formaldehyde is added. The ingredients are then stirred while air is bubbled through the ingredients until thoroughly mixed after which the pH of the mixture is adjusted to between 12.0 and 14.0. The adjusted mixture is now heated to a temperature within the range of 200.degree.-210.degree. F. and air is bubbled through the heated mixture until copper and copper oxide precipitates form in the mixture. After the precipitates form the mixture is allowed to cool to permit the precipitates to settle to the bottom of the vessel and the mixture is decanted from the vessel. The copper and copper oxide precipitates are washed and then collected.