Document 4JOeyLwdMqo4NnGBwrr5Nw9ej

E. I. DU PONT DE NEMOURS & COMPANY 256 VANDERPOOL STREET NEWARK, NEW JERSEY Serial No. Copy No. 1 KN 71-# 12 NEWARK PLANT PIGMENT COLOR RESEARCH REPORT CONTINUOUS YE--698--D - MIXING AND VARIABLE STUDY Period Covered JUNE 1970 - DECEMBER 1970 NJ 18179 FILE DATE 211.3 3/5/71 \ \ \ \ j N42410 1. Numerical Pile 2. Research Office Pile - 211,3 3. Newark Library Pile - 211.3 4. M.Hunt/E.Gonick, Pigments, Wilmington 5. W.S .Struve/J. Jackson/A. R.Hanke 6. R.H.Wetzel, Newport (circ. and Pile) 7. E.E.Jaffe/E. F . Klenke/B. H. Perkins/Library . 8. P.J.Monahan, Newark (Vital Records) 9. N-G.Fisher, Central Research Dept., Wilmington 10. Newark Library - for Central Report index 11. Newark Library - for Central Report Index 12. J.P.Higgins 13. I.H.Dunn/J.E.Copp 14. Extra 15. Extra 16. Extra 17. Extra 18. Extra KN 71-f Copy Ho. 12 NEWARK PLANT PIGMENT COLOR RESEARCH REPORT TITLE: CONTINUOUS YE-698-D - MIXING AND VARIABLE STUDY PERIOD COVERED: JUNE 1970 - DECEMBER 1970 SUBMITTED BY: J. F. HIGGIHS APPROVED BY: E. F, KLENKE, JR. Date Submitted: 2/16/71 3A/7/Date Released: ABSTRACT: Factors affecting the YE-698-D continuous process were studied in the laboratory continuous reactor, including mixing, acidity level, effect of splitstrikes, continuous acidity level control, and the effect of residence times. Recommendations for plant control variables were made. DUP050082624 INTRODUCTION YE-698-D has been prepared in the continuous unit about three times in the past few years. Although some reasonable quality products were obtained each time, the quality was not within stand ard limits. The runs were of too short a duration to evaluate variables and frequently periods of very poor quality were obtained. In view of the additional flexibility a working YE-698-D process would give the Newark Plant, it was decided to do further laboratory work to explore potential control variables and establish the principles upon which a workable process should be based. Previous laboratory work had been done in a gravity-feed laboratory continuous reactor, and had been of limited duration. By using a pump-fed system, designed originally for continuous azo work, a more reliable system was designed. Utilizing this system, which involved the first three tank analogs of 12 Building, the following areas were studied: 1. The effect of mixing per se On color. 2. The effect of acidity level on color. 3. The effect of split-strikes on color. 4. The utilization of continuous control of the acidity level. 5. The effect of residence time as a variable : to control color quality. EXPERIMENTAL EATA AND CONCLUSIONS A. Mixing The influence of agitation on the quality of the 2000#/hour concentration process for YE-698-D was investigated Agitation was provided by variable speed Lightnin1 mixers with a top speed of 320 rpm. A 60-30-10 split was employed. Tanks 1 and 3 were onehalf gallon jars, while tank 2 was a 15 liter high battery jar. Speeds were varied in 100 rpm increments in each of the jars. Exot. 1922-K--75 76 77 S0A B C 82A B Tank 1 320 220 120 120 320 220 320 220 Tank : 320 220 120 320 120 120 220 220 Tank 3 320 mo 220 120 320 120 120 220 220 Quality Satisfactory II Plop Satisfactory Sat.-dk. red ' SI red v. A wk. v. 80$ vs red v. 82a DU P050082625  **2* * Additional experiments at 320 rpm in all jars with reduced residence time in Tank 2 (from 12.5 mins* to 5*9 mins.) showed essentially no differences. The following conclusions were drawn. 1. A minimum level of agitation is necessary in all tanks to obtain a product in the YE-698-D quality range. This is probably related to lead excess and nucleation since only the first tank appears critical (K-77, K-80-B, K-80-C) . 2. inadequate agitation in the first tank can be compensat ed for by increased agitation in Tanks 2 and 3. This probably facilitates subsequent solid solution formation. 3. When agitation is nominal in Tanks 2 and 3, the agitation speed in Tank 1 affects tint and hue markedly (K-80-B and K-80-c) * Higher speeds gave a redder tint product prdbably by facilitating growth of larger particles. 4. Greater agitation in Tanks 2 and 3 contribute to weak ness of t 15% by indirectly facilitating crystal growth. Prom a practical point of view, this may indicate that stronger redder products may be obtained in the plant by reducing jet speeds in Tanks 2 and 3, provided Tank 1 is already adequately agitated. Generally the strength level is dependent on the acidity of the chrome and lead solutions* B. Acidity Level Study of the influence of agitation and acidity level on the color attributes of YE-698-D was covered* A 60-30-10 split was employed at two-agitation levels and three acidity levels. The acidity level is generated by adding a fixed quantity of nitric acid to the solution of sodium chromate/roolybdate/sulfate while holding the lead nitrate pH constant. The agitation levels evaluated were 1) 320 rpm in all three tanks. 2) 320 rpm in the initial tank, and 3) 120 rpm in the second two tanks. DUP050082626 -3 The data are as follows: Exnt, Mt - str (vs YE--698-D) 1st tank 320 rpm Aciditv Level 1st Tank p H All at 320 rpm 2nd + 3rd 120 rpm 1922-K (HN03) 87 1 (max) ' 2.65 - 2.75 dk 15% weak dk 10% weak 88 2 (2/3 max) 2.90 - 2.95 vs It 3-5% str s It 10% str 89 3(1/3 max) 3,15 - 3.25 It 20% str dull,muddy 20 str dk dull The following conclusions were drawn 1. A first tank pH range of 0.7 pH unit can cause a strength variation of Z 35%. 2. Acidity level substantially controls masstone depth and strength level, but mixing plays a roll. 3. Second and third tank agitation gives stronger products, with little masstone change except at the high strength level where the masstone and tint becomes dull and muddy. Practically speaking this may indicate that, on a plant basis in the continuous unit, a nitric acid feed to control strength should be considered. Additionally it suggests again that variable speed jets in the second two tanks may be important in process control. The demonstrated sensitivity of strength and masstone to acidity level suggests that improved OK straight on the batch level might be achieved by utilizing a concentrated chrome sufficient for Several batches, and pipeline diluting during the strike itself. G. Chrome Split A study of the system was conducted to determine the optimum chrome split in YE-698-D. The following conclusions have been drawn: 1. A 90-10 split appears to give the best quality with good strength and red tint (Exp, 97 + 98)- 2* a 100% introduction in the first tank may work if the residence times are reduced, to avoid weakness. DUP050082627 -4 Exot. 1922-K Tank (Avg. Res 1 Time-Mitt.) (1-10.3-1 ) JL 2 2, 91-A rpm 320 320 320 split 60 40 Rubout Str 10-15 X-RAY - Good pattern 91-B 92-A rpm 320 120 120 Dull MT.str More monoclinic split 60 40 - v.yellow (Electron micrographs also indicate more) (monoclinic in 91-B. ) rpm 320 320 320 split 60 40 v.s.wk. v.s.yellow Some excess monoclinic 92-B rpm 320 120 120 split 60 40 93-A rpm 320 320 320 split 40 60 s It MT.v.str. Excess monoclinic and v, yellow tetragonal solid so^n. Dt.str. yel. High excess monoclinic 93--B rpm 320 120 120 split 40 60 V.lt./ v.st. yellow(flop) Excess mono + str. tetragonal ss (flop) 94-A 95 rpm 320 320 320 split 10 90 V- It. str. yellow High mono and tetragonal (flop) rpm 320 320 320 split 10 90 Lt. str. Excess mono plus tetragonal (Electron micrographs show no change in particle size from (first tank to third tank. The particles are very small, (x-rays show no composition change. Here, all orange solid (solution formation and particle size growth took place in (the development (salt-HCl) step. 96--A rpm 320 320 320 Lt. str, split 10 30 60 [yellow Slight monoclinic (X-rays show progressive orange solid solution formation (in each step. Electron micrographs show growth in each (step. Indications are final formation was in development (step. 97-A rpm 320 320 320 split 90 10 St 15% s It NET | Excellent pattern red tint , (X-rays show almost complete orange formation by second (tank. Electron micrographs show substantial growth by (second tank. 98-A rpm . 320 320 320 split 90 10 atr.*5% dk MT Excellent pattern red tint s rede er 99-A rpm 320 320 320 , Dk wk red split 100 15%) Excellent pattern 100-A rpm 320 320 320 100 Dk wk (15)red Excellent pattern (s yel v. 99A) DUP050082628 -5- X-ray and electron micrographs of in-process samples in experiments 91, 95, 96 and 97 give a good picture of the effect of split and particle size. Experiment 95 shows that almost all growth and transformation takes place during salt development whereas the reverse split in Experiment 98 shows the opposite with Experiment 96 showing the stepwise approach. Based on the results obtained it was recommended to the Process Engineering group that a 90-10 split be tried in the next continuous YE-698-D run. D. controlled HHO* Peed YE-698-D strength may be controlled by introducing HHO3 in the first tank and omitting it from the chrome make using a 90-10 split. Study to optimize the conditions was demonstrated in Experiments 101-104. The advantage of this is a much more responsive strength control, correctible when necessary. It might be applicable to YE-421-D and YE-637-D as well. KxPt. 1922--K Tank (Avg. Res . Time-Hin.) a - 10.3 - 1 ) L11 Rubout 101 102 rpm 320 320 320 Str (93) split 90 - 10 (2.6m) s dk MT Adj pH 3.35 (first tank) separate HNO3 addition yell rpm 320 320 320 split 100 - HNO3 feed to pH 3.30 first tank. yellow v. YE-698-0 + 101 eq str 103 rpm 320 320 320 v. wk split 90 - 10 Ok MT (10.6 min) HNO3 adj to 2.95 pH 104 rpm 320 320 320 split 90 - 10 (2.6) HN03 to pH 2.80 v. wkDK MT X-Rav Tr monoclinic Seme mono tetragonal tr. mono deep valley SI excess mono trace tetragonal E. Residence Time Optimum conditions for the controlled strike pH Moly Orange process were determined. With a 90-10 split, by varying residence times and pH in the first tank, "OK straight" quality has been DUP050082629 -6 obtained, as veil as leads for variables* Optimum conditions are a strike pH of 3*30 with a short first tank residence time of about a minute; a ten minute second tank residence time and about two minutes in the third tank. By shortening the second residence time strong yellow material can be obtained? longer time resulted in slightly weak redder products* - EXDt. 1922-K 105 106 107 108 109 110 Tank Avg. Res. Time-Min. 1-10-1 rpm 320 320 split 90 - (2.6m) HN03 pH 3.15 320 10 rpm 320 320 split 90 - (2.6m) HN03 pH 3.30 320 10 rpm 320 320 320 split 90 - 10 (0 min) HN03 pH 3.35 rpm 320 320 320 split 90 - 10 (10.3 m) HN03 pH 3.3 rpm 320 320 320 split 100 - (10,3m) (2 m) HN03 pH 3,4 rpm 320 320 320 split 90 - 10 (13 m) HN03 pH 3.35 Rubout Dk MT v. Wk X-Rav Good pattern trace tetragonal Dk Str Yel Good pattern tt Some mono and Str Yellow tetragonal s dk MT 90 s red Good pattern Dk wk Good pattern tr. monoclinic Dk MT 105 R20 Good pattern DUP050082630