Home > Case Studies > Zinc Phosphate Case Study – Precoat Metals

Zinc Phosphate Case Study – Precoat Metals

Zinc Phosphate Sludge Removal

The Company

Since 1962, Precoat Metals has been a leading supplier of metal coil-coating services. Precoat’s business is to apply protective and decorative coatings to customer’s coils of steel and aluminum, using a continuous process coating line. In fact, with nine coating lines at seven plant locations, Precoat is one of the largest metal coil-coating companies in the world.

The Problem

On Precoat’s coil-coating line in Houston, Texas, zinc phosphate is applied to coils of steel as a protective coating. A by-product of the coating process is a sludge formed from the zinc phosphate, water and etching compound, which ends up settling to the bottom of the coating line’s tank unit. The more sludge that accumulates, the less efficient the metal coating process becomes. The zinc phosphate sludge which settled in the tank required periodic removal, using a contracted vacuum truck service every 3 months, costing Precoat $6,500 each time, plus costly downtime. At this frequency of cleaning, the company was looking at annual out-of-pocket costs of $26,000, plus production losses exceeding this amount. There had to be a better way.

The Solution

Precoat Metals had been using CentraSep fluid filtration systems on other coil-coating lines, but for different purposes. Precoat Metals asked the team at CentraSep Centrifuges if the CentraSep units would work to solve the zinc phosphate sludge removal problem. CentraSep accepted the challenge and after on-site material testing, concluded that their systems were up to the task. CentraSep installed a centrifugal liquid solid separator as part of the pretreatment section of Precoat’s coil coating line in 2002 and put it to work removing the zinc phosphate from the process water. The results were dramatic, with the CentraSep fluid filtration system paying for itself in less than two years.

Precoat Metals used CentraSep on their coil coating line, where the metal is phosphatized in preparation for painting.

The Benefits

  • Eliminates tedious and expensive “pump and shovel” tank cleaning
  • Reduces production downtime
  • Extends process fluid life
  • Improves heat transfer
  • Reduces labor costs
  • Reduces separated material disposal costs
  • Easy to maintain and operate
  • Simple, strong, and durable construction
  • Worry-free operation
  • In-use reliability
  • No filtering media required

How it works

On Precoat’s zinc phosphate metal coil-coating line, the sludge by-product is pumped directly to the CentraSep fluid filtration system, where – reaching spinning speeds up to 2,012 times the force of gravity – even the smallest particles of zinc phosphate are removed from the water and etching bath. The resulting fluids can then be recycled and reused in the coating process. The zinc phosphate particles are collected on the centrifuge’s bowl wall where after a degree of accumulation and based on a predetermined process cycle, they are automatically scraped off and discharged into a waiting receptacle. The filtering and scraping/discharge cycles of the CentraSep system are PLC programming controlled, allowing continuous cycling and operation with virtually no operator attention.

Reliability and Service

CentraSep fluid filtration systems are built to not only solve tough problems, but to be reliable and worry-free. All the parts that come in contact with the process fluids are constructed of 316 stainless steel for lasting dependability and ease of maintenance. “CentraSep has performed flawlessly and their service has been great” says Robert Pagel. “They installed the CentraSep system, trained our people and made sure everything was running smoothly… and they’re quick to respond whenever we need them.” Precoat Metals trusts CentraSep Centrifuges to help them maintain their high standards of quality and customer satisfaction. The CentraSep fluid filtration system worked to solve Precoat Metals’ zinc phosphate sludge removal challenge. It can work for you!

CentraSep Centrifuges

The CentraSep fluid filtration system is engineered by CentraSep Centrifuges, an innovator in environmental products and fluids management services. Since 1981 CentraSep Centrifuges has specialized in solving problems through application engineering. Nowhere is this problem solving approach more apparent than with CentraSep fluid filtration system, which was created after listening to client challenges and needs in the filtration and maintenance of process fluids.

Join the Revolution

If you would like more information about CentraSep – machine specifications and the technical data that would apply to your business – call us at 1-800-258-0099. We’ll analyze your unique challenges and show you how the CentraSep fluid filtration system can revolutionize your zinc phosphate process.

Top of Page