Document 44OLdXJKQ5jOD0yJRKm4Vog8V

umo U Til M VICK I'UKKIUKNT 25 Broadway New York Octcbf: 17, r. femes v. Lelst, Rennie, Davis, Kervln k FdmondB, 165 Eroadety, Net York City Re: Johnson st al Application Serial No. 178,511: for: DETKOD OF FPJDUCINC Thill_ IFAD Dear 11s: I am sending you herewith copy of letter Iron Hr. Johnson topeit< r sitfc a memorandum by Hr. Knox, which is self-explanatory. Fours rery truly, KS/ ?.nc . PN^0000a434 In t e r n a t io n a l Sme l t in g a n d Re f in in g Co mp a n y East Chicago, Indiana CP. lu. tJMOHuNuSgOtrN October 15th, 1940 PLANTS: East Chicago. lad. AJcron, Ohio Ur. Frederick Laist, Vice-President, ACKNOWLEDGED RECEIPT 1 ^ ^ International Smeltg. and Refg. Co., Room 17SO - 25 Broadway, New York, w.. y;. Re: Johnson et al Application Serial No. 17352 For: METHOD OF PRODUCING Dear Mr. Laist:- WHITE LEAD ~~ To avoid undue delay, in the absence of Mr. Case I am replying to your letter of September 25th, with attached copy of a letter from Mr. James Laist on the above-mentioned subject. We have carefully studied the suggestions given in Mr. James Laist's letter, and in reply to it we are attaching a memorandum by Mr. Knox, which we believe gives him the information desired for preparation of a suitable affidavit. We hope that thia information is sufficient for the purposes desired, but, if not, we will appreciate any further suggestions. -GEJ/s end. cc-Mr.F.O.Case PNYC00006435 N11211.01 V INTERNATIONAL SMELTING AND REFINING CO.. : 'e a s t CHICAGO, INDIANA '' MEMORANDUM TO Mr. G. E. Johnson, Plant Manager DATE October 4th, 1940 SUBJECT: HE: JOHNSON ET AL APPLICATION SERIAL NO. 178,352 EOR: METHOD OP PRODUCING _____________ WHITE LEAD In reference to Mr. James W. Laist's letter of September 24th requesting information for uae in the preparing of an affidavit in con nection with the above Patent Application:- The procedures outlined in Examples 2 and 4 of the Johnson Patent No. 1,845,713 were not carried beyond the experimental develop ment stage as it was found that while they represented a distinct im provement in controlling the composition of the precipitated White Lead, ,that in practice they would be uneconomical. Tests showed that in Example 2,.acetate ions, and in the case of Example 4 sodium ions, would have to.be added in amounts in excess of the normal losses of these com pounds and that their concentration would therefore rise to a point where a portion of the solution would have to be discarded, in order to permit lowering the concentration by diluting the solution with water. The added cost of these chemicals would have made procedures 2 and 4 too costly. The disadvantages of the foregoing procedures were eliminated while still retaining their improved control, when the procedure of the present invention was discovered. This improved procedure eliminates all need for added chemicals, and hence the added cost that made the earlier process uneconomical. In practice, the operation procedure followed in applying the present invention is to subject only a portion of the oatholyte to excessive oarbonation and to use the remaining portion of uncar bonated catholyte, containing sodium hydroxide, to add to the anolyte to establish the anolyte bicarbonate in the desired proportion. This practice is covered more concisely in Claim'No, 11, espec ially when the wording inserted in brackets in the following portion of this claim is added to the wording of the claims- Line 13 .....................................controlling the composition of the precipitated White Lead by reference to the bicarbonate concentration in the anolyte and adjusting the bicarbonate concentration in the anolyte by subjecting (a portion of) the catholyte to excess oarbonation and adding to the anolyte (the remaining portion of the) uncarbonated catholyte con taining sodium hydroxide to establish In the anolyte bicarbonate in the desired proportion. This improved procedure, that does not require the addition of chemicals, was an outstanding contribution to the cost of controlling the composition of the White Lead. It was not obvious to those skilled in the art as it was only recently discovered. The Invention has results in the production of a superior product at a substaitial reduction in cost as was set forth in the affidavit subscribed to on the twenty-first day of December, 1939. '' WJK/mm WhiteVUad Plant Sv^TTutendent PNTC00G08436 N11211.02