In the Netherlands, the cost of waste disposal is increasing fast. Moreover, government policy forces companies to research, develop and implement new techniques aimed at the recovery of the waste streams they produce. CIC International reacted very early on to this new trend and developed.
The so-called Total Solution offers several major advantages:
It has been developed by and for galvanizers
It is a flexible process.;
It involves very low disposal costs
No extra manpower is required
It represents a saving on basic chemical and zinc costs
The GalvaPress unit:
removes the Fe from the flux solution
requires expensive chemicals like NH3 and H2O2
can regenerate flux solutions as well as rinse and stripping solution
Description of the process
The rinse/flux/acid solution is pumped into a oxidation/neutralisation unit. Each solution requires a different treatment. The treatment and programming is determined and controlled by a PLC program.
In all cases the iron is selectively remove from the liquid and transformed into FeCl2/3 and/or Fe(OH)2/3
A option to this unit is a section were the Fe(OH)2/3 is dissolved in HCl. What remains is a FeCl2/3 that can be re-used in several different type of industries like domestic waste water treatment plants, for iron oxide production, dephosphating and as a flocculant for process or waste water.
The process is divided into 4 stages, namely:
Oxidation
Neutralisation
Filtration
Rinsing/Dissolving
The liquid is pumped into a oxidation unit were the FeII is oxidized into FeIII and mixed. During this process H2O2 is added. For the rinse water treatment this step of the process is skipped. From the oxidation unit the liquid flows into a neutralisation unit. In the neutralisation unit the pH value is adapted to the required value with either NaOH or NH4OH solution.
After neutralisation the sludge is separated from the liquid by a GalvaPress filter system. The cake is rinsed with water in order to remove most of the contaminants. The clear liquid is flowing into the bath.
The filter cake is manually removed. The cake can be dissolved in HCl. This is carried out manually.
The final FeCl3 solution is pumped into a storage vessel.
Flowchart: Integrated process water treatment unit (GalvaPress).
