Titanium Scrap Metal Processing
Background
A world-class processor of titanium scrap had a wash system whose cleaning solution was becoming contaminated with emulsified/water soluble oil that was being washed off of titanium turnings. As the level of emulsified oil contamination increased over time in the wash solution, cleaning effectiveness diminished. The carbon numbers of the cleaned, recovered titanium turnings exiting the wash system worsened over time and the client wanted to eliminate this problem associated with the critical measure of his end product quality. Subsequent rinses were becoming contaminated from drag out of emulsified oil, thus causing the discharge of the rinse water to the local sewer to approach and in some cases exceed discharge limits. Ultimately, dumping the spent wash solution and recharging the wash tank with a fresh wash solution was the answer to these operational problems. However, this approach for servicing the wash tank was expensive. There were labor costs associated with dumping, cleaning, and recharging the wash tank. Dumping resulted in disposal costs for the waste wash water. Recharging and reheating of the wash solution resulted in added chemical costs for new detergent and higher energy costs for reheating the solution. Additionally, there was lost production due to downtime for these wash tank services.
AquaChemical™ System
The Solution
The titanium scrap metal processor began a search for a better solution to the problems associated with their wash system. Their objectives were to extend the useful bath life, reduce wastewater volume being generated, ensure the quality of the washed turnings exiting the wash system, and reduce the drag-out of emulsified oil from the turnings into the rinse water to help meet discharge regulations. They selected the AquaChemical™ Microfiltration System from Separation Technologists to work in conjunction with the Suparator™ from Aqueous Recovery Resources, Inc. to accomplish these goals. The AquaChemical™ system employs a ceramic microfiltration membrane to filter and recycle aqueous alkaline cleaning solutions. The microfilter has a porosity of approximately 0.2 microns. The AquaChemical™ system removes emulsified oil from wash water, but it is not designed to remove excessive quantities of free floating, unemulsified oil, which is almost always present in these operations. These types of oils can reduce the AquaChemical™ system’s throughput if not properly pretreated. A device called the Suparator™, manufactured by Aqueous Recovery Resources, Inc., of Bedford Hills, NY, accomplishes this objective very well by removing unemulsified oil from the wash solution and is required for our AquaChemical™ to work at its optimum level.
This treatment approach allows water and soap to pass through the AquaChemical™ system’s microfilter elements, while removing water-soluble oil and solids from the wash solution. Thus, the wash solution is filtered and reused, while the oil contaminants are removed from the wash solution. The result was that they are washing titanium turnings with a wash solution that is consistently better over the long-term than before, which has resulted in less interruptions and better carbon numbers for the recovered turnings from the wash system. The wash solution itself is cleaner, with regards to oil content; thus the rinse water has less oil content from drag-out than previously seen. The drying process now produces less smoke from oil residue burning; thus the working environment has improved, which was an unforeseen, but welcome improvement to the processing line. With the use of the AquaChemical™ and Suparator™ systems, the processor has significantly improved productivity, cut operating costs, reduced waste, and has improved product quality from the washing operations conducted on scrap titanium turnings.
Suparator is a registered trademark and is used with permission of Suparator International b.v.