Abstract:
A method of treating photographic effluent containing one or more metal ions with an oxidation number greater than one, comprising the addition of a water-soluble silicate to the effluent in an amount to render it glass-like and less permeable to water. Conveniently the effluent has been treated by the addition of calcium hydroxide and the silicate, preferably 'water-glass' may then be added either to the treated effluent suspension and the mixture separated or to the pre-separated solid.
Abstract:
Beschrieben wird ein Verfahren zur Behandlung einer wässrigen, gegebenenfalls Schwer- und/oder Edelmetalle enthaltenden, cyanid- und/ oder komplexbildnerhaltigen Lösung, umfassend eine Hochtemperaturbehandlung der Lösung in einem geschlossenen Reaktionsbehälter, dadurch gekennzeichnet, dass nach der Hochtemperaturbehandlung ein Teil der behandelten Lösung aus dem Reaktionsbehälter abgelassen wird, der abgelassene Teil mindestens teilweise durch unbehandelte Lösung ersetzt wird und diese mit dem im Reaktionsbehälter verbliebenen Teil der behandelten Lösung hochtemperaturbehandelt wird. Darüber hinaus wird eine Vorrichtung zur Durchführung eines solchen Verfahrens beschrieben.
Abstract:
The invention relates to a method in connection with steel production for handling of hydroxide sludge formed in the neutralization of spent metal-contaminated pickling agents from a pickling step for steel, preferably stainless steel and for using calcium fluoride in the hydroxide sludge to replace the natural fluorspar as a fluxing agent in connection with steel production. Accordingly, the addition of the reactive neutralization medium is monitored by the pH electrodes operated in continuous fashion, and the pH value is adjusted at the range between 9,0 and 9,5.
Abstract:
The present invention provides methods and the use of compositions for removing substances from aqueous solutions wherein the pH of said solution is raised from acidic to basic. In these methods a composition containing Fe3+ and Mg2+ as sulfates is added to said solutions before raising the pH to settle said substances. The substances to be removed may be metals or heavy metals, such as complexed Cu-ions.
Abstract:
An efficient continuous flow device for water treatment using pulsed power technology, wherein untreated water flows as a thin film so that maximum surface area of untreated water gets exposed to plasma, and untreated water enters into plasma region and undergoes oxidation by different reactive oxygen species, then treated water is discharged through the reactor. Oxygen gas was purged into the reactor to decrease the nitrate concentration. With oxygen as the feed gas, the final nitrate concentration was found to satisfy the drinking water standards. To remove residual hydrogen peroxide, the plasma treated samples were incubated for 24 min with MnO2 catalyst.
Abstract:
The present invention refers to a method to remove organic chemicals and organometallic complexes (organic heavy metal complexes) using zeolite from process water or tailings streams of a mineral processing plant where diethylenetriamine (DETA) or triethylenetetramine (TETA) is used as a flotation reagent and DETA-metal complexes are found in process water or tailings streams. In a preferred embodiment, the process water or slurry tailings streams of a mineral processing plant containing DETA, DETA-metal complexes and residual heavy metals are contacted with natural zeolite. This can be carried out by adding the natural zeolite to the process streams (slurries) while mixing with a mechanical mixer to efficiently adsorb DETA, DETA-metal complexes and heavy metals from the process streams (slurries) on the zeolite. The loaded zeolite is then discarded with the flotation tailings.
Abstract:
The present invention provides for a method of producing a composition containing a polymer having undergone phase inversion, the method comprising the step of: effecting phase inversion of a phase invertible water insoluble polymer in an aqueous composition and the composition comprises a mixture of at least two different substances, one of which is a water insoluble dispersible polymer having undergone phase inversion while the other is optionally a contaminant.
Abstract:
A method of treating photographic effluent by precipitating or otherwise removing harmful pollutants to provide an environmentally acceptable liquid phase and a disposable solid phase. The pollutants are removed from the effluent by the addition of chemical reagents which sequentially cause different pollutants or their derivatives to precipitate. A time delay may be necessary between certain additions to allow completion of that reaction and prevent interference from other reactions. The method is preferably carried out in a single vessel.
Abstract:
The present invention relates to a method for treating an aqueous liquid effluent containing calcium and carbonate ions and containing precipitation-inhibiting products, said process comprising the following successive steps: a) providing an aqueous liquid effluent supersaturated with CaCO 3 and containing precipitation-inhibiting products; b) having the effluent obtained in step a) pass into a reactor with high solid content with a solid content maintained between 20 and 800 g/l and integrated solid-liquid separation, at a pH comprised between 8 and 9.2 allowing in a single step precipitation in situ of the aragonite polymorph of calcium carbonate and removal of the precipitation-inhibiting products; c) recovering an aqueous liquid supernatant containing a suspended solids content of less than or equal to 0.1% by mass of the solid content in the reactor, advantageously a suspended solids content of less than 50 mg/l, the precipitation-inhibiting products being phosphonates.