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Thermal Metal Treating, Inc. Amplate, Inc.  Quality Rolling & Deburring Co.

Technical Summary of PRO-pHx as used by Thermal Metal Treating, Inc.

January 2004

Thermal Metal Treating, Inc. has been using PRO-pHx since October 2001. The principle application has been as a purification additive for acids. HCl acid is used in the processing of stainless steel black oxide, ferrous metal black oxide, zinc phosphate, iron phosphate and manganese phosphate heat-chemical coatings. The HCl acid is used for the pickling and activation of carbon steels and stainless steels and/or the stripping of coatings such as zinc from various base metals.

The examples shown in the charts are for the two black oxide lines in which the HCL tanks are 125 and 225 gallons respectively. The tanks were first made up at 50% HCL acid at 20 degree Baume (by volume) and 50% water. They have been maintained at 40% to 50% acid and 1% PRO-pHx (by volume) and filtered since October of 2001.

Prior to using the PRO-pHx additive, higher than legal threshold levels of chrome showed up in the subsequent rinse tanks for the stainless steel black oxide line. Zinc and iron were also measurable throughout the rinse system on the ferrous line. Additionally, both HCL tanks were (Quarterly) waste treated because of the heavy concentrations of dissolved metals and organics.

Since using the PRO-pHx additive there is no appreciable chrome in the rinses systems, and the acid tanks no longer require waste treatment. The required maintenance is to: 1. Titrate the acid and make additions to maintain concentration. 2. Add 1 part PRO-pHx to 100 parts acid (by volume) when adjusting the acid concentration. 3. Continuously filter the acid tanks with a 10-micron cartridge filter and clean the filter weekly. Note: Any type of filter will suffice once you find the micron size best suited for your use.

The addition of PRO-pHx to these systems has resulted in a 96% reduction in hazardous waste (by weight), reduced system downtime for maintenance, reduced HCL acid use, reduced sodium hydroxide (for pH adjustment) use, less water use for rinsing due to the rinses receiving less contaminants, less use of the waste treatment system and the obvious reduction in waste treatment labor hours required.

TMT, Inc. is currently installing a simple filtration system, using the PRO-pHx additive, with intentions to also bring the rinses on the plating lines to zero discharge.


The following are the findings of Aqua Tech Environmental Laboratories Inc. of Marion Ohio. These figures are taken directly from their Certificates of Analysis. No chromium or zinc figures for the plating rinses are available prior to PRO-pHx use, because the heavily contaminated rinses were simply sent to the waste treatment system. There the chrome was reduced to the trivalent state and a standard pH adjustment, flocculation, filtration and independent lab testing were performed before the water was disposed of to the city sewer. After 9 months of similar positive findings, Thermal Metal Treating, Inc. was no longer required to use an independent laboratory for testing of the waste stream and currently does simple in house testing before rinse disposal. Note: UG/L = parts per billion.

Post HCL rinse on the Stainless Steel Black Oxide line after 9 months of PRO-pHx use

EPA Method Test Result Units WS#
200.7/6010B Chromium, Cr 1600 UG/L 30641
200.8/6020 Nickel, Ni 4500 UG/L 30630
200.7/6010B Zinc, ZN 910 UG/L 30641

Post HCL rinse on the Carbon Black Oxide line after 9 months of PRO-pHx use

200.7/6010B Chromium, Cr 41 UG/L 30641
200.8/6020 Nickel, Ni 180 UG/L 30630
200.7/6010B Zinc, ZN 110 UG/L 30641

Summation: Filtration of acids has lowered our operating costs, reduced our solid waste generation and eliminated independent lab testing of the rinse streams.

Mark Scott
Vice President
Thermal Metal Treating, Inc.

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