Abstract: A process is described for leaching gold and/or silver from ores or ore concentrates using an aqueous alkaline cyanide solution with addition of hydrogen peroxide. The addition of the aqueous H.sub.2 O.sub.2 solution is regulated and controlled through the concentration of the oxygen dissolved in the leaching solution, the leaching solution containing from 2 to 20 mg O.sub.2 and preferably from 7 to 13 mg O.sub.2 per liter. 0.5 to 5% by weight H.sub.2 O.sub.2 solutions are preferably added. The process is applicable both to leaching by agitation and to heap leaching, the addition of H.sub.2 O.sub.2 being regulated and controlled through measurement of the O.sub.2 concentration in the leaching solution and can also involve measurement in a measuring stream. Despite low consumptions of H.sub.2 O.sub.2 and NaCN, the gold yield is even increased in some cases and the leaching time shortened.

Abstract: A process for leaching gold and silver from ores and ore concentrates is disclosed using a cyanide leaching solution and hydrogen peroxide and maintaining an oxygen concentration of 2 to 20 Mg of O.sub.2 /liter. In the invention, leaching takes place in the presence of decomposition catalysts and preferably the formed cyano-complexes are separated during leaching from the leach solution. Decomposition catalysts are manganese compounds, present as 0.01 to 1 mg computed as Mn/liter of barren solution, or 1 to 50 mg computed as Mn per kg of ore slurry, or they are inorganic or organic polymers or carbon. Activated charcoal is preferred and simultaneously adsorbing cyano-complexes of precious metals. The process offers lowered consumption of H.sub.2 O.sub.2 and possibly cyanide and maximum gold yield in a shortened leaching time.

Abstract: This invention pertains to a method of treating cyanide contained in wastewater with particularly high levels of solids in the stream. The process involves either simultaneous or step-wise dosage of hydrogen peroxide in the form of an aqueous solution of a concentration between 35% to 90% by weight, preferably at least 50% by weight, and SO.sub.2 either in the form of gaseous SO.sub.2 or solution of sodium and/or potassium sulfite or metabisulfite resulting in the conversion of cyanide ions to non-toxic cyanate ions.

Abstract: Treatment of effluent containing cayanide is disclosed wherein a mixture of H.sub.2 SO.sub.4 and H.sub.2 O.sub.2 with between 0.01 and 0.5 moles of H.sub.2 SO.sub.4 per mole of H.sub.2 O.sub.2 is used.

Abstract: In purifying gas wash waters containing cyanide with formaldehyde, the exact dosing of formaldehyde presents a problem, especially with strongly fluctuating cyanide contents. By continuous potentiometric measurement in a side stream which is regulated to a pH of 7 to 10, while the pH of the main stream remains unchanged, the formaldehyde can be adjusted safely to any cyanide content.

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: The object of the invention is a process for recycling used lubricating oils. After drying and gasoline removal, the oil is distilled and then treated with sodium or sodium hydride in a finely-divided state at elevated temperature. This is followed by a further distillation. Both distillations are at temperatures below 300.degree. C., the oil fractions of low volatility being respectively distilled in a molecular distillation apparatus at below 2 mbar.

Abstract: In the detoxification of waste waters containing nitrite ions by means of hydrogen peroxide the addition of hydrogen peroxide is automatically controllable by adding the hydrogen peroxide continuously or in portions with continuous measurement of the pH and stopping the addition when no further reduction of the pH is caused by it. By control of the hydrogen peroxide addition through the change of the pH it is guaranteed that sufficient hydrogen peroxide is added to reach a complete detoxification of the waste water while on the other hand there is not wasted hydrogen peroxide unnecessarily.

Abstract: A method for reprocessing used lubricating oils is disclosed wherein the oil is dried, treated with finely dispersed sodium metal at elevated temperature, the remaining free or organically bound metal is decomposed by means of an active hydrogen containing compounds, followed by distillation of the oil for recovery.

Abstract: A process for the reprocessing of used lubricating oil wherein said oils are treated with a mixture of potassium hydroxide and sodium hydroxide.

Abstract: Copper (Cu.sup.++)-ions are separated from an effluent containing complexing agents which are ethylenediamine tetraacetic acid and/or diethylenetriamine pentaacetic acid or their anionic salts, by using an HS-containing triazine compound and Fe.sup.+++ -ions in a quantity at least equal to the amount of complexing agent.

Abstract: Cadmium (Cd.sup.++) ions are separated from an effluent containing complexing agent such as nitrilotriacetic acid, ethylenediamine tetraacetic acid and/or diethylenetriamine pentaacetic acid, or their anionic salts by using an HS-containing triazine compound and Fe.sup.+++ ions in a quantity at least equal to the amount of complexing agent.

Abstract: There is described a process for the production of inert solvent soluble metal alcoholate free from alcohol of crystallization by reacting an alkali metal with an alcohol in an inert solvent above its melting point in an emulsion of the alkali metal in a solvent.

Abstract: The use of a container in a metallurgical process, said container comprising two or more components which are clinched or crimped together, said container having contents which comprise an air, moisture, or air and moisture sensitive material, said use comprising introducing said container with its contents into a melt comprising at least one metal. The combination of the container and additive and an improved metallurgical process are also provided.

Abstract: Gypsum plaster having a delayed setting time is made by adding a mixture of mesotartaric acid and l-tartaric acid or d,l-tartaric acid or a mixture of l-tartaric acid and d,l-tartaric acid to the gypsum plaster.

Abstract: Caking of industrial alkali metal chlorides and mixtures containing them in storage is prevented and a flowable product is obtained by adding a hydrophilic and/or a hydrophobic material, in combination with a complex iron cyanide, on a hydroxyl group containing carrier to produce a permanent moisture content of at least 0.01 weight percent of water on the salt.

Abstract: Industrial gypsum plaster (plaster of Paris) having a delayed setting time is prepared by including D,L-tartaric acid and sufficient calcium hydroxide that a 5 weight % aqueous suspension of the plaster has a pH of at least 11.5.

Abstract: Caking of industrial alkali metal chlorides and mixtures containing them in storage is prevented and a flowable product is obtained by adding a hydrophilic and/or a hydrophobic material, in combination with a complex iron cyanide, on a hydroxyl group containing carrier to produce a permanent moisture content of at least 0.01 weight percent of water on the salt.

Abstract: Silver coatings in photographic tanks are dissolved with an aqueous solution of an alkali mono or di peroxysulfate, an alkali bisulfate and thiourea.

Abstract: There is prepared a powdery anticaking agent for inorganic salts based on (A) an iron cyanide complex, (B) a water insoluble inorganic, inert, finely divided hydroxyl group containing material or a material able to form this in the production of the anticaking agent, (C) hydrophobizing and/or (D) hydrophilizing materials in which (A), (C) and/or (D) are employed on component (B) as a carrier together with (E) water in an amount of 20 to 50 weight percent, preferable 35 to 45 weight percent. The composition is prepared by intensively mixing the carrier (B) in the corresponding ratio in the dry state with the active materials at room temperature and then adding to this mixture so much water that the active components go into solution and as such are absorbed on the carrier and regulating the pH to 7 to 9, preferably 7 to 8.