In an effort to offer customers a comprehensive product line of recovery products, Beta has been researching the best method to recover a flux tank.
The Problem:
Our fundamental challenge focused on removing dissolved contaminants such as ferrous and sulfate ions while retaining the essential zinc ammonium chloride which is in the flux. Another concern was the introduction of foreign chemicals.
We chose not to focus on conventional (dead-end) filtration in our design. In dead-end filtration, contaminants accumulate and blind the filter, requiring replacement. Plus, the best filter press might only remove suspended solids between 20 and 200 micron in size.
In-tank treatment by adding chemicals and waiting for the solids to settle was not a good option either.
High performance (< 1 micron) crossflow microfiltration membrane provided the cleanest alternative. Solids-laden solution is pumped at high velocity through the inner surface of these porous tubular membranes, scouring the surface to discourage deposition of the solids. Permeate (clean flux) migrates through the walls of the membranes and is returned to the flux tank.
We built our Pilot System last year. It uses barium chloride to convert the soluble sulfates into filterable solids. The iron is converted to ferric hydroxide solids using ozone gas.
The solids flow right through the microfilters while the solids-free flux permeates them and is returned to the flux tank. The solids return to the vertical tank, draining into an IBC tote at the end of the cycle. The membranes are flushed and soaked for four hours in five gallons of 5% HCl solution to restore their effectiveness.
The operator interface screen is simple, requiring very little time by a human operator. The PLC has been fitted with a cellular connection and webcam which allows monitoring and control by a linked user. This feature also enables remote customer support by our Beta engineers.
Material Costs —membrane replacement every 3 years. Other replacement materials include: pump seals and diaphragm pump seats/balls.
Daily Labor Costs = 20 minutes
Weekly Labor Costs = 20 min active time + 4 hours inactive time
Utility Costs —Electricity consumption similar to running a household dryer.
