Microfiltration

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Beta’s new Oxyfilter System extracts contaminants from flux tanks. Our system works continuously, maintaining a solids-free flux tank using filters which remove solids <1 micron.

  • Decrease gross zinc consumption
  • Improve skimming recovery
  • Decrease product re-run problems
  • Decrease dross production
  • Automation minimizes operator time

 

It's Simple Chemistry 

The Oxyfilter works for both Sulfuric and Hydrochloric acid users. The only difference between the two is that Hydrochloric acid users do not have Sulfate contaminants in their flux, so they will not require the Barium Chloride treatment step. 

The Oxyfilter simply converts the soluble impurities into insoluble solids which can be filtered out of the solution.

Ferrous Removal — The process of removing Ferrous impurities from a flux solution requires the conversion of soluble Ferrous (Fe+2) ions to insoluble Ferric (Fe+3) Hydroxide.

2FeCl2 + 2O3 →  2Fe(OH)3  + 4 Cl-

flux recovery - insoluble ferrous to soluble ferrous

The OxyFilter accomplishes this conversion using Ozone (O3), a form of oxygen that has one more oxygen atom than the oxygen (O2) we breathe.  Ozone does not dilute the flux bath during treatment and adds no unwanted residual chemicals.

Ozone is added to the ferrous.  Solids settle quickly.

flux recovery_ferric hydroxide settling

 

Sulfate Removal (for Sulfuric Acid users) — The process of removing Sulfate impurities from a flux solution requires the conversion of soluble Sulfate ions into insoluble Barium Sulfate solids. The most common method is to add Barium Chloride Dihydrate to create the insoluble barium sulfate precipitate.

SO4 + BaCl2 → BaSO4 + 2Cl

Sulfate + Barium chloride → Barium sulfate + Chloride 

  1. Barium chloride is added to flux.
  2. Solution is agitated as the salt quickly reacts.
  3. Filterable barium sulfate solids collect at bottom. 

Operation Diagram

Operation steps

Step 1. Flux Tank – First, the proper pH is maintained in the Flux Tank between 4 and 4.5.  Although the OxyFilter will not be affected by pH variation, it is imperative that flux chemistry be maintained within proper parameters to insure quality galvanizing. “A.C.N.” should also be adjusted as needed.

Step 2. Reaction Tank – Dirty flux is pumped to the Reaction Tank. If sulfuric acid is used for pickling, Sulfate ions will be converted into insoluble Barium Sulfate solids by adding a measured amount of Barium Chloride.  These solids are created so the Microfilters can remove the resulting Barium Sulfate suspended solids from the flux solution in Step 4. 

Step 3. Concentration Tank – In the Concentration Tank, soluble Ferrous (Fe+2) ions are converted to insoluble Ferric (Fe+3) Hydroxide solids using ozone gas. Beta developed a patented process to utilize over 95% of the ozone available to the system.

Step 4. Microfilters – After pre-treatment, the flux is pumped at a high velocity tangentially across the surface of tubular, microporous, < 1 micron membranes. The suspended solids travel quickly through the membranes and return to the Concentration Tank.  The solids-free flux solution permeates the membranes and returns to the Flux Tank. This is known as cross flow filtration.

At fifteen minute intervals, a small quantity of clean flux solution is driven backward across the surface of the membranes to clear any solids that may have built up. This “backflush” process is automatic. 

Step 5. Solids Handling – For plants with relatively clean flux tanks, an IBC tote will handle all solids discharged when the Microfilters are backwashed. The solids will settle to the bottom of the tote while the supernatant can be decanted back into the OxyFilter.  For plants with more contaminated flux tanks, a small Clarifier Tank and Filter Press can efficiently handle the solids.

Benefits

Electricity consumption – like running a household dryer.

Most customers will realize a payback in < 6 months. 

 

Sustainable Development

Beta Control Systems, Inc. was founded in 1980 with the corporate philosophy based on what was coined years later as “Sustainable Development.” We dedicated our resources to developing and applying technologies that would leave the smallest environmental footprint while remaining cost competitive with alternatives.

Our approach to microfiltration follows our original direction while also setting a new standard for low energy and low cost processing. We chose low energy state-of-the-art membranes, recover energy from the process, and avoid the use of dangerous, corrosive chemicals.

We learned from more than a quarter century of worldwide competition that having the Best Environmental Technology Available doesn’t matter if you don’t win the bid. We rely on innovation and cost engineering to keep our technology competitive while still meeting the customer’s goals.