Document o92RxZ2YO3G7O3gGjzRw318wE

E. I. DU PONT DE NEMOURS & COMPANY KREBS PIGMENTS DEPARTMENT 256 VANDERPOOL STREET NEWARK, NEW JERSEY Serial No. KN-44-46 Copy No. / LIEX \jt &RY COPY NEWARK PLANT PIGMENT COLOR RESEARCH REPORT J'iaal Report Sick List Study - Lead Nitrate Process Period Covered! Octcbai* 1941 - May 1942. FILE: DATE: ,121 1-1 7--2J>--44 NJB6&9 N37959 i7 Serial So. KH-44-46 Copy Bo. / Copy 'tot #1 - Numerical MX* 2 - Research Office (121.1-1) 3 - Library File (121.1-1) 4 - #10 Building File 6 * Imperial Chemical Industries, Ltd. 7 . b g ,, h it a 9 Mr. C. H. Rupprecht, Wilmington (ICI File) sum PLANT PIGMENT COLOR RESEARCH REPORT Titles Final Report f1 l Sick List Study - Lead Nitrate Process Period Covered* October 1941 - May 1942. SUBMITTED BY* APPROVED BY: L. Stsmart fa/rf V. Chaiupski 7 DATE SUBMITTED; 7-8-44 DATE ISSUED: 7-25-44 DUP050149851 2- mimaaa Early in October 1941 the plant issued a Sick List Request stating that chrome yellows were running dirty la masstone sad poor in lightfastness* This was readily traded to impure lead nitrate* At that time, lead nitrate was made by dissolving pig lead and/or lead sludge from the tri-basic lead acetate process in a dilute nitric acid solution} purifying by precipitating the Im purities} and clarifying by filtering out the various impurities. The purified lead nitrate solution was pumped to the color making area as needed thru iron pipes* Details may be found in the following formulas, notes, and reportss- SP-10, K-3983 - the manufacture of lead nitrate from pig lead. SF-9 , K-8984 - the manufacture of lead nitrate from TBL sludge. 8E-7 , E-9028 - the removal of iron from lead nitrate solutions. KR-38-718 - the manufacture of lead nitrate. KS-36-596 - the purification of lead nitrate. The initial investigation showed that the poor quality of the lead nitrate was due to the following conditions:- 1, Large quantities of brown sludge (high in iron and other impurities) were found in all the scale and storage tanks. This indicated lack of control of the lead nitrate acidity and equipment failure. 2, The filter press which was supposed to remove solid impurities was in very poor condition and as a consequence large amounts of these impurities were passing thru the press into the finished lead nitrate storage tanks. The electric eye which is located on the filtrate discharge as a protection against press leakage was not functioning because of its poor mechanical condition. 3. Standard operating procedures were not being observed by the operators* In several instances it was found that the operators were using methods which differed from standard and from operator to operator. 4. The standard operating procedures were found to be in need of revision at several points because of changes In equipment and methods which had been made during the past several years without being Incorporated into standard procedure. The general condition of the lead nitrate equipment and operation is quite clearly shown by the plant records which indicated that approximately one-third of the lead nitrate manufactured at that time was unsatisfactory for use In the manufacture of chrome yellows. DUP050149852 3 the following stops wore taken to eliminate these sub standard conditions*- y - 1* the iwpities (tootp sludge) were removed from "the seal tanks, storage tanks, eta*, and attention called to the foot that the' cleaning schedule was not being adhered to. 2. the operating procedures were revised, where eo.*p?y, and . copies posted on lie bulletin heard in the leadshep for t&g ^Orators guidance. Shi* was followed by a period of training . daring which the details of the various operations were carefully explained to each of the operators. 3* ill of the defective c^nipjaeBt was replaced as rapidly as possible and several rearrangements made to give smoother and more efficient operation* Details concerning the substandard conditions found and the corrective measures applied are fully covered In the various memoranda, letters, etc., issued during this period. Copies of these are to be found in 038-44-13. Xa general, standard process as it existed at that time was satisfactory provided the proper supervision was supplied and standard procedures observed* This is clearly shown by the following tables- Period Oct. 12 to Oct 31 (1941) Bov. 1 to Bov. 13 Bov. 15 to Nov. 30 Dec. 1 to Dec. 15 Dec. 15 to Dee. 23 January 1942 % of lead nitrate mfg. jsamtlglftffiteaa. Experience has shown that lead nitrate made foom pig lead does not contain sufficient impurities to require purifi cation. For economic reasons, however, it Is necessary at times to consume certain lead sludges which accumulate over a period of time in the lead liquor and lead nitrate processes, it such times it is necessary to purify the lead nitrate solution because of the relatively large amounts of impurities present in the lead sludges. DU P050149853 Barly in January 1942 the plant proposed that a program he organised to study the elimination of the purification step in order to effect laborsand yield savings and free the purification equipment for use in the manufacture of'copperas* this'was to he accomplished as follows* ~ ice lead sludges were to he consumed uniformly in all hatches of lead nitrate* ' n$Sa$t> a small amount being added to each lead nitrate "make**, so . that at no time would there be the possibility of more than a slight increase in impurities* The lead nitrate solution would then he run to a settling tank to remove the undissofved sludge, and after settling, run off thru a standpipe to the storage tanks*' A trial run was arranged |or the period January 12-January 18, 1942 under the supervision of the Research Department* During this period 30 hatches or 115,000 lbs* of lead nitrate were made from pig lead and 741G lbs* of TBu sludge. After the run, 795 lbs* of this sludge were found in the settling tank and 53 lbs* In the finished liquor storage tanks* The results Indicated that the method was a workable one but required very close supervision and adherence to standard procedure* Although the Research Department was skeptical that these conditions would be met, the process was written up (SF-10, g-1720) and supervision of the process turned over to the plant in May 1942* 0^1^1-1720 KCK-120 DUP050149854