Document VJbV3gjkMg7zMRVZJXXazR1Dp
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E. I, DU PONT DE NEMOURS & COMPANY KREBS PIGMENTS DEPARTMENT 256 VANDERPOOL STREET NEWARK, NEW JERSEY
Serial No, KN-51-44 Copy No. i. Numerical
NEWARK PLANT PIGMENT COLOR RESEARCH REPORT
X Final Report
EXAMINATION OF LEAD BEARING RESIDUES FOR CONVERSION TO LEAD NITRATE
Period Covered
NOVEMBER 7, 1951 - DECEMBER!, 1951
4 NJ 8747
FILE: DATE:
121.1-1 December 18, 1951
DUP050068738
Copy to:
#1 - Numerical File 2 - Research Office File (121.1-1) 3 - Library File (121.1-1) 4 - H. Arnoul/Plant File 5 - J, N, Tully/A. Siegel 6 - G. R. Cantwell/J. H, Bailey 7 - Extra a-
Serial Ho, KH-51-44 Copy Ho, 1, Numerical
NEWARK PUNT PIGMENT COLOR RESEARCH REPORT
Final Report
EXAMINATION OF LEAD BEARING RESIDUES FOR CONVERSION TO LEAD NITRATE
NOVEMBER 7, 1951 - DECEMBER 1, 1951
Charges 1101-31-3 (BCN-31-3)
SUBMITTED BX APPROVED BT
DATE SUBMITTED: 12/7/51 DATE ISSUED:
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mmiDOCTION
This report eummariaes work on substitutes for corroding grade pig lead. Part of the work was carried out in conjunction with the Quality Control Group who have been working on the general program of pig lead substitutes for some time. The materials examined during the course of this work were:
1. lead Flue dusts from Bars Smelting and Refining Co., Philadelphia, Pa.
a. combined flue dusts b. reverberatory flue duat
2. Electrotype residues from Essex Metals Co., Newark, N. J. ON 1872 6/11/51
SUMMARY AND CONCLUSIONS
1. Lead nitrate solutions have been made from Bers Reverbera tory flue dust, or combined flue dusts, which have the following characteristics:
a. Excessively high chloride ion content (in excess of 50 parts f1,000,000) despite the fact that residues had been washed with water prior to nitric acid attack* See letter attached - X* B. Magruder, Jr.
b. The lead nitrate (N-41) solutions require modifications of the standard Y-469-B process (omission of halogens, increased heat development period) to make laboratory preparations of reasonably good quality Y-469-D possible*
e. Examination of N-41 solutions from Bars dusts have shown the following impurities:
fl) Cl- (51-1672) (51-1676, 1677) 2) Minor amounts of Mg, Zn, Ca, Cd, Na (51-1676) '3) Minor amounts of Na, Ca, Zn, Mg (51-1677)
2. The maximum extent of conversion from dust to soluble lead nitrate under practical conditions has been in the order of 2056 of the total nitric acid soluble lead reported in the sample
3. These data indicate that Bars Reverberatory sludge or combined sludge is not a suitable raw material for the manufacture of lead nitrate by a process analogous to the one presently in use by the plant. The possible utility of this material after reduction to metal lic lead in a blast or electric arc furnace might be worthy of consideration if no more preferable forms of residues are found.
4* Lead nitrate of satisfactory quality can be made from electrotype dross. The Cu and Sb impurities in this material can be quantitatively removed by electrodeposition with metallic iron.
5* The separation scheme Pb++ * PhSOj, ** PbCCH * PbtHChte with removal of all soluble impurities by filtration and washing of precipi
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tate failed to yield a product of satisfactory quality when applied to lead nitrite solution made from Essex Metal dross. Further purifi cation by means of Y.P.S. treatment might make such a system satisfactory.
6. * All residues used In lead nitrate manufacture Should be freed from water soluble impurities Such as Cl", SO//", etc. prior to
nitric acid conversion.
7. Quantities in excess of the following amounts of impurities* expressed as a % of the lead nitrate weight, have been found detrimental to quality in Y-469-D type processes.
a. 1$> Ga b-ltf Mg C-4.S# Zx k U.5% Ni
C<2.
b. The use of sodium ferroeyanide will not quantitatively remove Zn, or Mi from lead nitrate solutions, although
in the case of the latter some beneficial effect results.
PATENT REVIEW
Nothing of a patentable nature has been developed in these
studies.
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EXPERIMENTAL DETAILS
The Chemical Division's participation in this matter started on 11/7/51. The original objective was the evaluation of a sample of lead nitrate liquor made by Quality Control from Bare combined flue dusts.
This original objective was expanded on 11/9/51 to full scale cooperation with Quality Control in all matters related to the manufacture of lead nitrate from lead dusts or drosses under consideration, and was terminated on I2/3/5I* due to a change in the lead supply situation.
The following activities have been stressed during this period?
A. Evaluation of Quality and Yield of lead nitrate ex Bare Smelting and Refining Company flue dusts.
B. Purification and evaluation of lead nitrate ex electrotype dross (Essex Metals OU 1872).
C. Determination of effects upon Quality of possible metal impurities.
1- Examination of N-41 Solutions ex Bars Combined flue dust
A sample of lead nitrate solution (51-1672} was submitted to
the Chemical Division by Quality Control for functional test in a Y-469-D type process. An examination of this material showed the presence of excesp quantities of Cl* which in fact had partially precipitated out of the cold solution as PbClg. The bulk of the PbClg wae removed by filtration and a functional test made in s Y-469-D process. All halogens used in the standard process were omitted, and the heat development cycle
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was increased from 15 to 25 min. at 200*F because of the observed tendency for yellows from such N-41 liquors to convert from the rhombic to monoclinic phase at a slower rate than normal. These tests demon strated that the lead solution used in this fashion was equivalent in quality to standard plant N-41 solutions. (See 1421-2).
Quality Control subsequently prepared N-41 solutions 51-1676, 51-1677 by preleaching Bars dry flue dusts with water, prior to nitric add attack, to reduce the Cl- content in the resultant N-41 solution. This was found to be unsatisfactory, because appreciable amounts of Cl~ were found in the N-41 solutions, despite the fact that the original material was washed to a very low Cl- level. These solutions were tested in a Y-469-D process and one of them was found to give a satisfactory yellow (51-1677), the other an unsatisfactory yellow ($1-1676). Spectrographic analysis of the lead nitrate solutions utilised showed the presence of minor amounts of Cd in the sample 51-1676 which in all probability accounts for the inferior performance of that sample. Samples 51-1676 and 51-1677 were prepared for extraction in different fashions .i.e51-1676 wan calcined jprior to water wash and 5l-l677>was not. whether or not this is the basic reason for the different Cd contents cannot be stated from the information at hand.
Analysis of Pb(N03 )g Solutions ex Bers Combined Dusts
% Pb(N0 )2
gr/ml Total solids
Pb(N03)2 MSBik~
Uniden tified
solids
Soluble Cl- of %
Pb(N03>2
51-1675 calcinedunleached
13.26
51-1676 calcined -leached 27,14
51-1677 leached
24.50
.166
.360 .315
.366
.463 .407
.202
3.01
.102 .092
/ ' .96 1.43
2 - Selections of Berg flue dusts
A trip to the Bers Smelting and Refining Company was made on November 10, 1951 by the writer. Hr. R. Gedd of Quality Control and Mr. E. W. Roberts, metallurgist with the Engineering Department, The purpose of this trip was to ascertain the nature of their processes withtfae possibility of obtaining materials with a lower content of chloride or other impurities. Mr, Robert's report summarises our findingsg and a copy of this is attached. Material supposedly lower in chloride content was available from the reverberatory furnaces and samples were obtained*
3-,.= head. Yield_on,Nitric,,Acid_Atfc.ack, of Bers Rsvarboratorr Sludge
An analysis of the results of experiments conducted by Quality Control indicated the possibility of very low solubility of these sludges in nitric acid. The analytical method used by the Plant Analytical
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Laboratory uses a very large excess of nitric acid (134 mols HHOo/mol Fb) to determine total soluble lead in a given sample. This is obviously far in excess of any reasonable operating excess for plant practice.
An experiment was planned to determine the effect of varying
tha ratio of nitric acid to lead or preleached Here reverberatory sludge.
The following table summarises the data obtained in this study
__ pggTrff
Wt.of dry Molar Wt.of Sol. # of Wt.Cl' Wt.of 8W %0 ^oti
sludge* ratio Pb(N03)% theoret. parts Insol. 801 801* ft
Qcmr.1 a 1. gf.. HH03/Pb rgOOTSI^d PbtBOj^ ll22SiS2>
Fb
A
405 2.5/1 .61.66
20.7
56.7 327.4 15.7 *22 59-5
B
405
5/1 65.12
21.6
56.0 327 14.27 .19 60.(
c
405 7.5/1 76.66
19.5
57.0
324.4 13.52 .13 60.;
D
405
10/1 76.67
19.5
64.4 329.4 14.1 .14 59. ?
* Sludge 60.9# HKO3 soluble Pb (dry basis) 65.34# total Pb (dry basis)
These data indicate the following:
1. Preleaching of reverboratory residue has not lowered Clcontent to a limit considered safe for stainless steel.
2. Recovery of nitric acid soluble lead lies between 19-20# under the experimental conditions tested with a maximum of 91# of the total lead accounted for.
3. Analysis of the residue shows a small amount of water soluble lead, a considerable amount of nitric add soluble lead, but in an amount not sufficient to account for the missing yield.
4. Possible explanations for these low conversion results under these experimental conditions are:
(a) oxidation of PbS -* PbSOL in dilute nitric acid (b) lesser solubility of PbS04 in dilute HH03 versus
higher solubility in the more strongly acid solutions used in the Plant Analytical method.
5. No functional tests have been made on these solutions*
These results indicate that Bern reverboratory sludge is not a suitable raw material for the manufacture of lead nitrate by a process analogous to the one presently in use by the plant. The possible utility of this materialrfter reduction to metallic lead in a blast or
electric furnace might he worth consideration if no more preferable
forms of residues are found.
.M
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4 - Purification of Lead Nitrate from Electrotype Residues
A. Quality Control has studied lead nitrate made by attacking electrotype dross with nitric acid and found that it is readily soluble* This material contains a high percentage of impurities as can be seen from the following tables
Analysis of Essex
lle^ti>t^e_Jroag M*lk 1872J
Cu 2,6
Sn 4*7
Sb 3.2
Fe *57
Hi .16
Hitric acid soluble Pb
69
Total Pb
71*8
Cl** Positive Qualitative test
6.8*
5*16*
3*32%
,*2l%f
71*1*
75*77%
This material was found to be unsatisfactory because of the high Cu, Hi and Sb content* Attempts to purify such solutions by means of interaction with freshly precipitated PbS were made by Quality Con
trol without complete success*
A successful separation of the Cu and Sb from the lead nitrate has been made by means of metal replacement with iron (which can be more easily removed).
Cu++ + Fe -* Fe++ * Cu*
2 SB*** + 3 Fe * 3 Fe++ + 23b
Such solutions, either before or after filtration of sludge remaining from nitric acid attack, can be quantitively freed of copper by iron replacement at a pH of 2*5 and temperature of 160-180*F. The reaction time will of course be dependent on surface area of iron exposed* Subsequent removal of the copper-plated iron and copper dust, followed by HgOg treatemnt of the filtrate to oxidise Fe,f+ to Fe+++ end
pH adjustment to 3*5, was found to precipitate iron to the usual extent reached in N-41 plant practice Clarification of the solution gave no appreciable difficulty*
Cost of HgOg Treatment
Assume Cu 4 pts/70 pts Pb
Baaia 207# Pb - ft.; 20.7 - 11.S2 # Cu
Cu++ + Fe
Cu* + Fe++
63*54 56
/'a lbs. Fe++ to be oxidised by H2O2 "
11*82 x 56 10,3# 63 *5
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2 Fe{NO3 )2 H202 + 2HNO3 ** 2 Fe(HOj )3 + 2H20
i4A x 34 * 3.H # H2O2 at + .75/* lb, * *2.35 per
* * 50
**
207 fPb
331 fPbtSO^Jjj
Solutions made in this fashion were found to be satisfactory by standard Cu, Fe and Sb tests, but contained Cl* and Ni44, An attempt to remove the latter by means of a Y.P.S, treatment was not fully suc cessful, (due apparently to the much lower solubility of lead ferrocyanide). However, the yellow produced by the Y.P.S. treated N-41 was better than untreated H-41 in lightfastness,
H-41 made in this fashion compared satisfactorfly against standard N-41 plant solutions in a Y-469-D procedure, despite the presence of 01* and Ni44.
B, A further attempt to purify this liquor by means of the sequences
(1) Pb44 + Cu44, Fe444, 8b444, 01" + SO,4 -* PbS04+ soluble Impurities to be removed by filtra tion and washing
(2) PbS04 + Ha2C03 ** Pb CO3 + Na2 S04 filter off PbC03- wash out SO^
(3) PbC03 + 2HHO3 * Pb(N03)2 C02 + f^O
was unsuccessful. The final N-41 solution contained excessive amounts of Cu44, Fe* , and 01" but was free of Hi44, and Sb444, This material was unsatisfactory in a functional test as Y-469-D. The impurities present must have been adsorbed during precipitation of the PbS04 and Pb CO3, and could not be completely removed by washing,
5 - Effect of Impurities in N-41 Solutions
Functional teats have shown that amounts of metals in excess of the quantities suggested below are definitely harmful to Y-469-D type processes (expressed as % of Pb(N03)2 ),
,5% Cd (found in N-41 ex Bers Dross 51-16761
kM Zn, ,5# Ni, 15S Ca, 1% g
Attempts to remove 2n44 from/soitutiona with sodium ferrocyanide have been shown to be unsuccessful, presumably because of the greater insolubility of Pb2Fe (Cltlg under the conditions tested. Amounts of Y.P.S. equal to twice that required by the zinc present were insufficient to remove all of the zinc.
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Typical Analysis Bers Combined
Ktefc Separation Dry Basis,,
Total Fb HNO3 sol
9b Sn Bi Fe Cu
As S Zn H2O
70.18 69.96
3.10 .06 .04
2.23 .012
0.011 .051 7
.03 19.67
56.32
56.04
3.71 .04
.084
5.62
.55,, ,008
.09 ? .012 .10
Qfiailt.ative tuto Co++ ". 01`. 8`. S4* S0` ^Cprea0nt
1. DSN 51-33 23. MKBon1t4h2ly1-S1u-9mmary Inorg. lab* November - December 1951
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