TMT 15 for precipitation of heavy metals from sewage
Heavy metals are met both in sewage, and in the fulfilled gases and in connection with the toxicity and a wide circulation represent special danger for environment. If they are in the water or vegetative nutrients get to a food chain they can cause an irreversible damage for the person.
To lower influence of heavy metals on environment, the legislators have established limiting values for sewage and gaseous emissions, to exceed which it is not allowed. Observance of these limiting values demands special and frequently expensive actions for clearing, for example, for sewage from galvanic manufacture or a metal-working industry. At clearing of gaseous emissions wet washing is applied to, by which eventually, the sewage appears as well, containing heavy metals.
Usually heavy metals besiege and allocate from sewage by neutralisation with the help of liquid caustic soda or to exhaust in the form of almost insoluble hydroxine. However this method refuses in many cases, as sewage often contain so-called complexing agent. They keep heavy metals in a solution and interfere or make negative impact on sedimentation hydroxine, it appears not possible to maintain the ordered limiting values.
This problem can be solved by means of application TMT 15, special besieging means of firm «Evonik Degussa GmbH». TMT 15 forms with heavy metals of connection which are much more difficultly dissolved, than corresponding hydroxine. Thus when sedimentationof hydroxine does not give sufficient result in connection with presence complexing agent, it is possible to achieve considerably the best results of branch.
The active substance in TMT 15, reacts practically as trivalent anion and can connect three equivalents of heavy metals thereby. Deposits can be considered as metal-TMT as metalloorganic macromolecules. TMT 15 reacts according to it as a complete molecule.
Products of reaction of heavy metals and TMT have extremely weak solubility in water. They contrary to sulphides do not become again soluble throughout a wide range pH. Sedimentation by means of TMT 15 is usually spent at pH 6-10. In case of some metals it is possible to work, however, and in more sour or more alkaline environments.
Water solution TMT ready to application 15 can be applied within the limits of various variants of a way, for example:
- In case of sewage with high concentration complexing agent at which sedimentation hydroxine completely refuses;
- In the step of sedimentation, following sedimentation hydroxine, when in connection with presence complexing agent by means of sedimentation hydroxine the partial decision is reached only. Here TMT 15 besieges the remained residual metals.
The requirement in TMT 15, depending on molecular weight of besieged heavy metal, makes from 6 (mercury) to 20 (nickel) of litres TMT 15 on kg of heavy metal. In practice, at first spend to laboratories some optimising tests, proceeding from analytically established maintenance of metals and corresponding quantity TMT 15, and the results received thus transfer then on industrial conditions.
The Company «КНТ Plus» is ready to give you consultations.
Sedimentation of heavy metals can be spent standing and flowing in the ways. In both ways usually the stream of sewage at first will be neutralised in the amalgamator by means of acid or alkali, then are added TMT 15 and polielektrolit-koaguljant. In a standing way a deposit metal-TMT can then be besieged in the same capacity after amalgamator switching-off. In a flowing way the deposit is besieged in separate capacity in which mixing is not made. In both cases slime then it merges and dehydrated by means of a filtering press.
TMT 15 within many years with success, it is applied as besieging means in various branches - beginning from galvanotechnics and chemistry to power stations and mining. Along with the efficiency and simplicity of application ТМТ 15 gives a number of other advantages:
- TMT 15 possesses favorable toxicological and ecological properties.
- TMT 15 - "is not poisonous" and "is not unhealthy" in sense of the international laws on chemical substances and is not dangerous cargo in sense of the international transport instructions.
- TMT 15 at storage and application does not form toxic products of disintegration of type carbon sulphure or hydrogen sulphide.
- TMT 15 operates in a wide range of pH both in sour, and in alkaline sewage.
- TMT 15 does not suppose any unpleasant smells.
- Deposits metal-TMT well coagulate and are also easily allocated from sewage and easily dehydrated.