Document x13kp57g9YE4b2GkoYMGRMEOE

December 22nd, 1939 ATS. VAIL ast. femes W. L&tst ' Pennle, Darla, Marvin end Edmonds 165 Broadway Hew fork. New fork fl i I j Dear Slri- \ I am returning ^lyrtaohed'v |the revised af fidavit vhioh aocompanih^ibyour l^ter of Deoember 19th. X bellere your rexfa^bn of this affidavit oorrectly deaafcibea thdsljjprovemeat. The affidavit haa been completed by filling in the blank apacee end by having itVkecuted for/Tiling. Very truly youra, WJK/mat end. ootHr. 7. 0. Caae .Mr. 1 Laiat/ Wa. J. iCnoz White lead Plant Superintendent N11314 PHXC00006 D4947 IN THE UNITED STATS1* PA'PBNT OFFICE In re application of GUNNARD E. JOHNSON and REGINALD G. BOWMAN and 'WILLIAM J. KNOX, JR. Serial No. 178,352 Piled Jn- - -Mr " ''"w. Div. 56 - Room 4725 ) ) ) ) ) ) ') ) ) ) ) METHOD OF PRODUCING WHITE LEAD AFFIDAVIT STATE OF INDIANA ) ss: COUNTY OF LAKE ) William J. Knox, Jr., being duly sworn deposes and says: I am one of the applicants in the above-mentioned application. . . I am employed by the International Smelting and Refining Co., and I am thoroughly familiar with the White Lead Plant of that Company at East Chicago, Indiana, where white lead is produced electrolytically. I am and have been for .the past 14 years Superintendent in charge of this White Lead Plant. Since the invention described and claimed in the above-mentioned application was made, it has been employed in the White Lead Plant and has resulted in considerable savings as compared with the processes previously employed there, including the process described in United States patent No. 1,845,713, and in the production of a superior white lead product. Variations in the chemical composition of white ' lead pigment have a marked effect on the oil-absorption or N11314.01 ; pNYCOC008460 oil-taking property of such pigments. The magnitude of this effect is shown in the following table, in which is'set forth the oil-absorption or oil-taking property of the pigment as determined by the three methods most commonly used by paint technologists in determining the amount of oil required to produce a paint of brushing consistency. Product "A" Product "3" Product "0" Analysis - Percent COg " PbC03 " Pb{OH}p Primary Oil Absorption (gms/lOOcc) Consistency (Stromer- Krebbs Units 35$ oil) Flow (Gardner flow meter. 35$ oil) 11.15 67,70 32.30 13.5 9.2K 2.2" 11.75 71.20 28.81 11.5 9. N 2.75" 12.40 75.30 24.80 8.5 7.4N 3.6" Up until the time the invention described in the above-mentioned application was made and put into use, the COg content of the white lead product produced at the White Lead Plant varied in normal operation of the plant franr 11,40$ to 12.10$. The COg content of the white lead product made at the White Lead Plant since the said invention was there put into use varies in normal operation of the plant from 11.72$ to 11.76$. This product is more uniform than and hence superior to the product formerly made.- The process by which the improved product is made differs from the process by which the former product was made only in that the method described in the'above-mentioned application for controlling composition of the white lead product has bean substituted for the methods previously employed, among which was the method of exact neutralization or accurate deficient carbonation described in United States patent No. 1,845,713. According to the process of the United States . patent No. 1,845,713, a considerable period of time was . 2- required to effect adjustment of the composition of the white lead product. This period, which amounted on an average to about 50 minutes, was a result of the time required for the following chain of events to take place before actual adjustment of the composition of the product could occur: (1) Titration of eatholyte at frequent intervals. (2) Adjust- ~nt of carbonation fan damper to increase or decrease degree of carbonation of eatholyte. (3) Time required to displace old eatholyte in storage tanks, piping:, and cells by new eatholyte of adjusted carbonate-to-hydroxide ratio. (4) Time of adjustment of composition of anolyte by flow of eatholyte ions of new ratio from eatholyte to anolyte compartment of cell. In accordance with the method described in the above-mentioned application, steps (2), (3) and (4) set forth above are eliminated, as it is only necessary to change the setting of one valve to vary the volume of alkaline solution flowing into the anolyte and so to adjust the bicarbonate ion concentration of the anolyte, and thereby to adjust the composition of the white lead product. Moreover, the number of control titrations that are required have been greatly reduced. As a result of these savings the period required to effect adjustment of the composition of the white lead product has been reduced to about 8 minutes on the average. ' The method of the invention described in the above-mentioned application has resulted in substantial operating savings. For example, to control operation of a tank room containing forty-eight cells by the process described in United States patent No. 1,845,713 required one circulation man, one titration man, and two cell men. Under- - 3- PN If COO 00 84 6 2 the method described in the above-mentioned application only one circulation man and one cell man are required to control operation of the same tank room. Subscribed and sworn to before me this 21st day of December, 1939. Notary Public - 4- PNYC00008463