Übersetzung für "Schwermetallfällung" in Englisch

Alternatively, the heavy-metal precipitation may also be effected prior to the Ca precipitation.

The H 2 S contained in the biogas is depleted in the RoHM reactors and used for the heavy metal precipitation process.

The centrifugate from this centrifuge is discharged via a lock 18 and is immediately subsequently subjected to a precipitation of heavy metals at 19.

For this purpose, it is proposed to cool the centrifugate subsequently to the precipitation of heavy metals with part of the air extracted from the sewage-disposal plant, in particular with part of this air extracted from above the settling basin, which air is subsequently used, after having been heated by waste steam of the lock and waste heat of the combustion, as hot combustion air in the combustion step.

These compounds disproportionate at high temperatures such as those prevailing in exhaust gas purification reactors to form sulfide and sulfate which are especially advantageous for the separation and precipitation of heavy metals.

In application, the sulfite component produces an immediate binding of the remaining oxide in the treatment medium, which prevents a reduction of the precipitation effect of thiocompounds in heavy metal precipitation.

These washings can either be conveyed alone to the mixer 2 or together with the washings 17 of the residue from combustion treatment unit after precipitation of heavy metals.

For solving this task, the invention essentially consists in that the centrifugate of the centrifuge subjected to the action of saturated steam is discharged via a lock and is immediately subsequently subjected to a sulfidic precipitation of heavy metals and in that the solid matter separated within the centrifuge are discharged via locks and optionally are subjected to a post-drying step and at least partially to a combustion step, for example to a fluidized bed combustion, for producing steam for the centrifuge, noting that the steam is as a whole recycled within a closed circuit and the waste steam from the lock is utilized for heating air, whereupon the condensate formed is supplied to the preliminary settling basin of the sewage-disposal plant.

On account of the centrifugate of the centrifuge subjected to the action of saturated steam being discharged via a lock and being immediately subsequently subjected to a sulfidic precipitation of heavy metals, the residual heat of the centrifugate is already utilized at this occasion.

Sodium sulfide is for instance usedintanneries as depilatory, in the organic chemistry as reduction agent, in the waste water treatment as heavy metall precipitation as well as for manufacturing sulphur dyestuffs.

In doing so, it was realized that the precipitation of heavy metals in an alkali solution buffered with calcium hydroxide, and without previous oxidation of low-valent metal salts, surprisingly takes place substantially completely.

Since the injection of CO 2 shifts the pH into the acidic range, it is, however, to be preferred to perform the destruction of the sulfide anions directly after the precipitation of the heavy metals.

The solid is incinerated and the liquid phase is fed firstly to a heavy metal precipitation operation (RoHM=removal of heavy metals).

Here, the phosphating bath overflow and/or the rinsing water is subjected to a recovery method such as e.g. reverse osmosis, an ion exchange method, nanofiltration, electrodialysis and/or heavy metal precipitation after the phosphating, and the aqueous phase depleted in metal ions here is used as rinsing water in each case for rinsing the metal parts to be phosphated after they have been cleaned.

An amount of approx. 30,000 m³/a freshwater could be saved in the treatment plant, while equal amounts of water did not need to be channelled through the in-house waste water treatment plant for heavy metal precipitation and the communal waste water treatment plant for nitrate decomposition.