Abstract: The present invention provides a gel having excellent separation ability, operability and a long life, for separating useful components from a rhodanate-containing detoxication treated liquid. The gel consists of a cross-linked polymer with more than 50 weight % of repeating units which are composed of 2,3-dioxypropyl (meth)acrylate or 2,3-dioxypropyl (meth)allyl ether, and whose average particle diameter is more than 10.mu. and gel water content is from 30 to 150%. The present invention also provides a method of separation using said gel.

Abstract: A process is described for the substantially complete recovery of cyanide reagent and metal forming water soluble metal-cyanide complexes contained in mill effluents and waste waters. The process is comprised of a loading cycle wherein the metal-cyanide complexes are adsorbed onto a basic ion exchange resin and the free cyanide containing column effluent is returned to the mill. The metal ions, which are usually mostly copper, nickel and zinc, and the complexing cyanide are eluted in the subsequent regenerant cycle by an acid solution having controlled pH and controlled redox potential, the latter being measured against the saturated calomel electrode. The preferred oxidant to control the redox potential of the regenerant solution is hydrogen peroxide. The generated hydrogen cyanide is sparged with air, or removed by subatmospheric pressure from the regenerant solution, and dissolved in an alkaline scrubber solution for reuse. The metal ions are recovered from a bleed solution.

Abstract: A process is described for the treatment of waste liquor containing a mixture of alkali metal or ammonium thiocyanate and polysulfides to convert the latter to the corresponding sulfates. The waste liquor is admixed with concentrated sulfuric acid under turbulent mixing conditions and in an inert atmosphere. The treated liquor is purged of gaseous by-products using an inert gas (e.g. carbon dioxide) and the purged liquor is treated to recover sulfate therefrom.

Abstract: Hazardous waste containing inorganic compounds which contain heavy metals or particular hazardous anionic groups or which are hazardous halides or non-metal oxides or sulfides is contacted with molten aluminum to provide reduction to lower less hazardous oxidation state.

Abstract: A method for treating a heavy metal-containing liquid, such as a wastewater stream, oil for recycling, or other metal-bearing liquid, with a trithiocarbonate, particularly an alkali metal trithiocarbonate, such as sodium trithiocarbonate, to precipitate the metals as insoluble sulfides. The precipitated metal sulfides are recovered as a low volume sludge, which can be processed through standard metallurgical techniques to yield the metals in economically useful forms. Among the most unexpected results produced by this method is the lowering of the selenium content in a naturally occurring body of water from 1.0 ppm to 0.0015 ppm.

Abstract: Noble metals are recovered from their cyanide complexes in aqueous solution by reaction with red phosphorus. To this end, red phosphorus is used in quantities of 1 to 5 weight %, based on the aqueous solution of the noble metal cyanide complex, in combination with an additional strong oxidizing agent.

Abstract: A process for producing a non-hazardous sludge from an aqueous solution which contains heavy metals comprising the steps of: (a) adding phosphoric acid or an acid phosphate salt to the aqueous solution to precipitate the heavy metals; (b) lowering the pH of the solution to less than about 5.0; (c) adding a coagulant to the solution; (d) raising the pH of the solution to above about 7.0 by the addition of a calcium source; and (e) dewatering the resulting non-hazardous sludge.

Abstract: A process for removal of iron cyanide complex or complexes from a solution is described, the process being characterized by contact of the solution containing the complex or complexes with ammonium polysulfide or sodium polysulfide, or a mixture thereof, at a temperature of from about 110.degree. C. to about 180.degree. C.

Abstract: Hexacyanoferrate ions are removed from washing waters using a weakly basic anion exchanger of the acrylic type containing tertiary amino groups. The anion exchanger is treated with an alkali metal hydroxide and an alkali metal dihydrogen phosphate solution.

Abstract: A process in which ferric ion in water-soluble form is added to an effluent containing cyanide, arsenic and antimony and having a pH of about 5 to 9 and treating effluent with SO.sub.2 and oxygen in the presence of soluble copper to produce a treated effluent having very low contents of cyanide, arsenic and antimony.

Abstract: A process for treatment of cyanide-containing aqueous effluents in which ferrocyanide present is precipitated with a metal other than copper, preferably zinc either prior to or simultaneously with the treatment of the effluent with sulfur dioxide and air in the presence of soluble copper.

Abstract: A method of removing complexed zinc-cyanide from wastewater involving a multiple stage process including, in a first step, control of ferrous ions to a critical minimum concentration of 250 to 400 ppm, together with pH control in the first and also a second step, together with recycling of a portion of sludge precipitated in the process. Improved sludge stability is achieved by aeration to oxidize precipitated ferrous hydroxide to ferric hydroxide, immediately before settling the sludge in a thickener.

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: Effluents from cyanidation operations are treated by contacting the effluent with powdered sulphur and iron to reduce the base metal content and cyanide ion content of the effluents.

Abstract: A method of removing complexed zinc-cyanide from wastewater involving a multiple stage process including, in a first step, control of ferrous ions to a critical minimum concentration of 250 to 400 ppm, together with pH control in the first and also a second step, together with recycling of a portion of sludge precipitated in the process.

Abstract: The cyanide content of waste waters containing the same is removed by treatment with sulfur dioxide or an alkali or alkaline earth metal sulfite or bisulfite in the presence of excess oxygen and a metal catalyst which is perferably copper.

Abstract: The invention provides an improvement in the disposal of a waste water coining iron-cyanide complexes including ferricyanides by the reduction of the ferricyanide ions into ferrocyanide in the presence of a zinc salt to precipitate the ferrocyanide ions in the form of zinc ferrocyanide. The improvement comprises the use of a sulfite, e.g. sodium sulfite, and a thiosulfate, e.g. sodium thiosulfate, in combination as the reducing agent whereby the reduction of the ferricyanide ions is complete within a relatively short time without being affected by the atmospheric oxygen or other factors.

Abstract: A condensate which contains cyanide ions, hydrogen sulfide and ammonia is first partly purified by stripping with water vapor and stripped-off gases are then scrubbed with an absorbent. The laden absorbent contains 50 to 300 grams ammonia and 10 to 100 grams hydrogen sulfide and is at a temperature of 70.degree. to 150.degree. C. and has a pH value of at least 9. Sulfur is added to the condensate or the laden aqueous absorbent in a quantity which is at least 0.8 times the quantity that is stoichiometrically required to convert the cyanide ions to thiocyanate ions. The sulfur may be produced from hydrogen sulfide and oxygen, preferably in the presence of an oxidation catalyst. Alternatively, the sulfur may be added to a liquid which contains 10 to 400 grams ammonia and/or ammonium ions per liter so that ammonium polysulfide is formed. That solution is mixed with the liquid that contains cyanide ions.

Abstract: Process for treating liquid waste compositions which contain copper ions and a complexing agent for the copper which includes reducing the concentration of copper ions in the waste composition to less than about 8 ppm and contacting the composition with H.sub.2 O.sub.2 ; and then contacting the waste composition with an ozone-containing gas and irradiating with ultraviolet light.

Abstract: A method for environmentally upgrading waste water containing formates, cyanides and ammonia is disclosed. Formates and cyanides are biodegraded by aerobic bacteria immobilized on the disks of a rotating disk contactor. Ammonia is air stripped.The present method eliminates the steam stripping stage of conventional processes as well as the lime addition and precipitation stages.

Abstract: The concentration of cyanides in the sour water system of FCC reactor is controlled by injecting such an amount of ammonium polysulfide (APS) into the system that the weight ratio of net free sulfur to simple cyanides in the sour water is about 0.6 to about 3.8. The pH of the sour water is at least 8.0.

Abstract: A process for the destruction of cyanide in an aqueous solution containing an iron cyanide complex wherein the pH of the solution is adjusted to be between 11 and 12 and the solution is irradiated with ultraviolet radiation. The pH of the solution is subsequently reduced to between 8 and 11, hydrogen peroxide is added, and the solution is then reacted absent further radiation.

Abstract: Cyanides, thiocyanates and metal cyanide complexes present in an aqueous solution can be biologically degraded by certain mutant strains of the species Pseudomonas paucimobilis. Such microorganisms are useful in the biological treatment of cyanide-containing wastewaters.Pseudomonas paucimobilis mudlock was deposited at the ATCC on Nov. 3, 1982, and granted accession No. 39204.

Abstract: This invention relates to an improved process for treating a cyanic liquid containing copper(I) cyanide complex ion which comprises heating the liquid at a temperature of not lower than 200.degree. C. in the presence of a water-soluble metal hydroxide, whereby the decomposition of the CN group of copper(I) cyanide complex ion is accomplished in a high rate in a single batch producing a relatively small amount of sludge even when the liquid has a high CN concentration.

Abstract: When aqueous solutions of a metal cyanide complex are detoxified with hydrogen peroxide, a residue of cyanide remains, which in the case of nickel for example may be present as Ni(CN).sub.2. In a process according to the present invention the detoxification of aqueous alkaline solutions of a metal cyanide complex is carried out using a restricted amount of certain complexing agents together with the hydrogen peroxide. A particularly suitable example of such complexing agents is ethylenediaminotetraacetic acid. It is especially preferred to use the complexing agent in a mole ratio to metal of from 0.8:1 to 1.5:1, together with hydrogen peroxide in a mole ratio to cyanide of from 2:1 to 3:1. The process is well suited to the treatment of concentrated solutions of cyanide, in many cases at least 4000 ppm, for example those resulting from the stripping of nickel plating.

Abstract: There is provided a continuous process for the lowering of the content of toxic materials in waste waters which also contain other oxidizable materials by quickly and continuously ascertaining the requirement of hydrogen peroxide, namely by potentiometric determination of the oxidizing agent requirement in a branched-off side-stream using a strong oxidizing agent, such as peroxymonosulfate, peroxydisulfate, permanganate, hypochlorite or ozone, which acts more quickly than hydrogen peroxide under comparable conditions.

Abstract: Cyanide degrading fungi are grown in the mycalial form. The mycelium is then immobilized and the immobilized mycelium used to degrade cyanide ion in cyanide containing effluents. At least 95% of the cyanide ion is degraded.

Abstract: A process for continuous treatment of a liquid containing a nickel cyanide compound which comprises (1) continuously supplying the said liquid containing a water-soluble metal hydroxide in a content of not less than 0.5 mol per mol of the nickel cyanide compound to a continuous reactor through a supply pipe, steam being introduced into the supply pipe so as to heat the said liquid to a temperature of 175.degree. to 200.degree. C., (2) passing the said liquid through the reactor while maintaining the said liquid at the said temperature and (3) discharging from the reactor the liquid having a CN content lower than that of the liquid prior to the supply to the reactor.

Abstract: Process for the recuperation of an insoluble salt of a metal from the rinsing solution of an electrodeposition of the metal.

Abstract: A process for treating a cyanide and cyanate-containing aqueous influent such as a wastewater stream is provided. A two-stage method is included for destroying a cyanide-containing influent which comprises;(a) introducing said cyanide-containing influent into a first ozone-contacting zone;(b) contacting said influent in said first zone with a second ozone-containing gas, at least a portion of said second ozone-containing gas comprising a first ozone-depleted gas withdrawn from a second contact zone to form a first cyanide-depleted effluent and a second ozone-depleted gas;(c) introducing said first cyanide-depleted effluent into a second ozone-contacting zone;(d) contacting said effluent in said second zone with a first ozone-containing gas to form a second cyanide-depleted effluent and a first ozone-depleted gas;(e) withdrawing said first ozone-depleted gas from said second contact zone; and(f) withdrawing said second cyanide-depleted effluent from said second zone.

Abstract: Ion exchange techniques are utilized to treat waste water flows, especially those from plating baths, by passing the waste water through a multi-level ion exchange resin bed, the bed thereafter being regenerated by a series of steps, including backwashing, passage of an acidic regeneration fluid through the bed, multi-stage rinsing of the bed, and passage of a caustic regeneration fluid through at least a portion of the bed. Acidic waste flows developed during regeneration steps are, when desired, further treated to recover cyanide values therefrom by heating same within a generally closed tank to drive off a hydrocyanic gas, which is then reacted with caustic within a circulation reactor having an inclined passageway in order to form and recover a cyanide salt liquor suitable for re-use in the plating bath.

Abstract: Cyanide (free or as a metal complex) dissolved in an aqueous solution such as waste waters is substantially completely removed by the addition of ferrous bisulfite which forms insoluble Prussian blue and other non-toxic reaction products.

Abstract: A method of removing ammonia from a wastewater containing free and fixed ammonia said process comprising the steps of: distilling the wastewater to remove the free ammonia; treating the distilled wastewater with soda ash to decompose the fixed ammonia; and distilling the treated wastewater to remove the decomposed ammonia.An apparatus for removing ammonia from a wastewater containing free and fixed ammonia comprising: an ammonia still for removing free and fixed ammonia; a source of soda ash solution; and means for feeding the soda ash solution from said soda ash source to the ammonia still to decompose the fixed ammonia.

Abstract: In a process for pretreating hazardous waste prior to solidification the waste is received in containers (10). The containers are deposited in a large vessel containing a chemical pretreatment media (9) and subjected to an agitating process in the vessel whereby the containers are ruptured and their contents deposited in the media. Neutralization, precipitation and chemical modification processes are envisaged in the container. After pretreatment the liquid is removed for ultimate solidification.

Abstract: Spent aqueous liquor containing cyanide, as from ore treatment, is passed through a bed of suitable anion-exchange resin to segregate the cyanide, which is subsequently recovered in regeneration of the resin by weak alkaline solution. Both the eluted cyanide and the alkaline regenerant are recycled, if desired, for further ore treatment. A most important benefit of such procedure is nearly complete elimination of cyanide as a component of the treatment effluent. Free cyanide may be separated from complexed cyanides when present by using weak alkaline regenerant to elute the free cyanide from the resin and stronger alkaline regenerant to elute the complexed cyanides.

Abstract: A method is disclosed for removal of free and complex cyanides from water-containing industrial effluents and wastes by treatment with insoluble solid iron sulfides at a pH in the range of about 7.0 to 8.5. The insoluble solid iron sulfides can be chemically prepared prior to treatment or prepared in situ, usually of a particle size smaller than about 5.mu., or supplied in the form of naturally occurring iron sulfides such as pyrrhotite or pyrite having a particle size smaller than about 300.mu., preferably smaller than about 150.mu.. The weight ratio of iron sulfide to total cyanide in the effluent is greater than 2:1, preferably greater than about 5:1 for prepared iron sulfides and greater than about 100:1 for mineral sulfides. The presence of a reducing agent such as ferrous ions or sodium sulfite to maintain a non-oxidizing environment during treatment enhances removal of cyanide.

Abstract: Removal of cyanide in wastewater treatment improved by initially contacting a rich cyanide bearing stream with activated sludge at a pH within the range of 3-6 upstream of the wastewater treating plant.

Abstract: The present invention relates to a process of water treatment, particularly of industrial aqueous effluents and of water from watercourses, such as rivers, lakes, ponds, and the like, comprising oxidation with singlet oxygen.