Document Nebm7rzyqeXRy3RMG6amOpBjV

RESTRICTED - USE IN DOW ONLY DOW CHEMit&L U.S.A. Texas Division CHLOR-ALKALI DEVELOPMENT Status Summary PLAINTIFF'S EXHIBIT January-February-March, 1972 DISPOSAL OF ASBESTOS FROM CHLORINE CELL CATHODE WASHING OPERATIONS - Problem b93 V. H. Maudlin OS `i82011 iSI Purpose Devise a feasible ay*tea for removal of bulk asbestos from the cathode vash vater and for elimination of fibers from the effluent waste. Procedure A supply of feed slurry vas obtained from the existing facilities at the Dow Industrial Service site. This material vas diluted or concentrated to 0.10 solids to agree with the expected teed concentration from washing facilities being designed. The prepared feed vas then put through a test apparatus fabricated from four Inch diameter by six feet high Plexiglass tubing and measurements made of the flow rates and concentration of the underflow and overflow. Measurements were made both with and without a flocculating agent, Purofloc A-23. Data Feed Cone. * .063 .088 .100 .028* Underflow Cone. % .k66 .311 .322 1.00 OPM/Ft.2 2.02 2.1b 2.1b 6.60 Diameter fo* 1500 kpm 30.8' 29.7' 29.7' 17.0' Solids in 1300 gpm Lbs/Hr. b75 660 . 750 280 Using Purifloc A-23 at a rate of 10 ml of a 0.2f solution to 5 gallons of slurry. Discussion The settling rates of the solids hav increased considerably from the time the initial test vas made on the D.I.S. slurries. This is confirmed by the fact that D.I.S. vas having to use less vacuum trucks to remove the same amount of solids. The only differences discovered in the operation are the amount of cathodes requiring acidizing, from a high of 30 percent to less than 3 percent and the continuous 2k hour per day operation of the washer instead of the previous 16 hours per day. In the last run using Purifloc, the settling rate vas ao great that the operation of the test apparatus became difficult. The continuous removal of solids was hindered causing difficulty in maintaining a consistent feed alurry 27Disposal of Asbestos from Chlorine Cell Cathode Vashing Operations -2- Conclusion This data indicates a thickener of 20 to 30 foot in diameter could be feasible. However the problem needs more study in a more suitable test device. Future Work An order has been placed with the Denver Equipment Company for a Laboratory thickener vhlch is a three feet diameter by three feet deep thickener complete with overflow launder and rake assembly with a lurry pump on the underflow. This equipment is scheduled for shipment on April 18th. * Preliminary arrangements have been made with the Komline-Sanderaon Company to rent a pilot plant size vacuum filter. Plans are to use this equipment at the D.I.S. site and obtain data on actual continuous basis. ISI*i820i * 4-11-72 bvc \