Determination of high carbon and high sulfur by the - stahl

Determination of high carbon and high sulfur by the - stahl

Abstract No. 17
Determination of high carbon and high sulfur by the infrared
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absorption method
GUO Fei-fei*1,2ˈZHOU Yu-hong1,2ˈHU Xue-qiang1,2ˈHouHong-xia1,2
(1. China Iron & Steel Research Institute GroupˈBeijing 100081,China˗
2. NCS Testing Technology Co., Ltd, Beijing 100094, China)
Abstract˖
˖In this paper, determination methods of high sulfur in copper
concentrate and high carbon in recarburiser was established by the
combination of high-frequency combustion with tube furnace - infrared
absorption instrument. Finally ˈ sulfur in copper concentrate was
measured by high-frequency combustion - infrared absorption method,
and carbon in recarburiser was measured by tube furnace - infrared
absorption method. For high sulfur in copper concentrate, flux, dosage of
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sample and curve of work were investigated and the results showed that
the optimal analytical conditions were as follows: 0.045g copper
concentrate + 0.1g Sn + 0.3g Fe + 1.2g W. Four samples were analyzed
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and the results showed the relative standard deviation (RSD, n=5) were
about 0.5%, which was agreement with the combustion neutralization
method. For high carbon in recarburiser, dosage of sample and
temperature of furnace were investigated. The results showed that the
optimal analytical conditions were as follows: 0.2g - 0.3g recarburiser,
temperature of furnace 1200 Ԩ. Four samples also were analyzed and it
was showed the relative standard deviation (RSD, n=3) was RSD_C%
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<0.5%. In addition, the determination of carbon in these four samples was
carried out by the recovery experiments with the recovery of 98.82%105.37%.
Key words ˖ high-frequency combustion ˗ tube furnace χ infrared
absorption method˗copper concentrate˗high carbon and high sulfur
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Determination of carbon ,sulfur
and nitrogen in recarburizer
Feifei GUO
NCS Testing Technology CO.,LTD
May 21st, 2015
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Outline
Background Experiment
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Results
Acknowledgement
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Background
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Application
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Recarburizer
Smelting -Steelmaking
1.Recarburizer is an additive used steelmaking.
2.Adding recarburizer can increase the carbon content.
3. Casting costs are reduced. Because It can increase the amount of
scrap and reduce the amount of pig iron.The price of pig iron is higher.
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Why to determin?
Carbon is the main ingredient for
recarburizer.The higher carbon content,the
better.
Sulfur and nitrogen both are impurity
elements,the lower content ,the better.
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But because of the price and the different
manufacturing techniques,some elements
content need to be determined in order to
ensure recarburizer meeting requirements.
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Why our methods?
Our methods are quick,convenient and less pollution.
Methods
Carbon
Combustion - neutralization method,
coulometric method
Sulfur
Gravimetric method,
Combustion titrimetric method
Nitrogen
None
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Element
For the above methods,analysis time is long,many chemical
reagents are used.
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Experiment
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Instruments Sulfur
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Carbon
Nitrogen
CS-2600
N-3000
Resistance furnace combustion infrared absorption method
Pulse melting -inert gas protection thermal conductivity method
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Standard samples
Sample No.
Material Carbon
Sulfur
Nitrogen
The spectrum
pure
graphite 99.99%
---
---
GSB06-2103-200
7
GBW11126a
GSB06-2106-200
7
GSB06-2111-2007
coal
90.26%
0.20%
0.56%
coal
80.03%
0.26%
0.25%
coal
81.45%
0.40%
1.31%
coal
79.02%
0.58%
1.03%
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Composition and structure of the recarburizer and graphite or coal is very close.
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Method Optimization
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Determination of carbon and sulfur in
recarburizer by CS-2600
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Choice of the temperature
1300was selected in this experiment.
Temperature
/
Carbon
Found w /%
900
1000
1100
97.73
98.04
97.93
97.43,97.13,
97.81
97.56,97.95,
97.70
1200
1300
Sulfur
Average
w /%
---
---
---
97.79
97.74
RSD
Found w /%
%
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0.2473
---
0.2571
---
0.3008
0.36 0.3702,0.3776,
0.3669
0.3681,0.3765,
0.21
0.3797
Average RSD%
w /%
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---
---
---
--
---
1.48
0.3715
0.3748
1.59
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Referance for YB/T 1430-1997,weight of recarburizer was 0.2g
and grain was less than 0.2mm .
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Releasing curve
Carbon
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voltage
Sulfur
time
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Calibration curve
Carbon
Sulfur
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R(linear correlation coefficient)
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Method Optimization
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Determination of nitrogen in
recarburizer by N-3000
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Calibration curve
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Nitrogen
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Sample
preparation
Be dried about 1hour in oven at 105.
The choice of sample grain:
120 mesh was selected.
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Sample -grain
1#-80 mesh
Found w/%
0.623,0.536,0.610,0.560,0.568
RSD /%
7.83
1#-120mesh
0.613,0.583,0.5760.606,0.588 2.37
1#-150mesh
0.578,0.602,0.595,0.596,0.603
2.41
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Chioce of analysis power
We selected 4.5kW.
Analysis power
/kW
4
4.5
5
Found w/%
0.5062,0.4987,0.4898,0.5124,0.4765
0.5768,0.5576,0.5612,0.5433,0.5569
0.5678,0.5431,0.5529,0.5376,0.5628
Chioce of flux
Average
w/%
0.4967
0.5591
0.5528
RSD /%
2.54%
1.92%
2.06%
We selected nickel bag.
Nickle bag
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Nickel foil (tailing)
Results
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Precision and Accuracy of Carbon Resistance furnace combustion -infrared absorption method
Carbon
Sample No.
1#
2#
3#
4#
Found w /%
Average w /%
RSD%
99.85,99.72,100.00
97.68,97.69,97.43
92.97,93.73,93.72
76.10,76.46,76.09
99.86
97.6
93.47
76.22
0.17
0.15
0.47
0.27
Added/g
Total found /g
0.1801
0.1820
0.1805
0.1816
0.1821
0.1812
0.3787
0.3784
0.3675
0.3528
0.3488
0.3577
Recovery rate
99.11
99.89
96.90
109.77
108.57
110.65
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Carbon of
Sample No. recarburiser/g
0.2002
0.1966
2#
0.1926
0.1529
0.1511
4#
0.1572
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Precision and Accuracy of Sulfur Resistance furnace combustion -infrared absorption method
Sulfur
Sample No.
1#
2#
3#
4#
2#
4#
Average w /%
RSD%
ND
0.368,0.376,0.380
0.199,0.191,0.200
0.138,0.141,0.135
ND
0.375
0.197
0.138
ND
1.59
2.35
2.11
Sulfur of
recarburiser
/g
0.00078
0.00074
0.00074
0.00028
0.00028
0.00027
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Sample No.
Found w /%
Added/g
Total found /g
Recovery rate
0.00040
0.00041
0.00040
0.00040
0.00040
0.00041
0.00117
0.00118
0.00115
0.00068
0.00069
0.00072
97.50
107.32
102.50
100.25
101.91
109.43
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Precision and Accuracy of Nitrogen N-3000-Pulse melting -inert gas protection - thermal
conductivity method
Sample
Nitrogen PMA-1000
No.
Average
RSD
Found
w/%
%
w/%
0.577,0.558,0.561,0.543,0.557
0.559
1.92
0.554
1#
0.0572,0.0595,0.0591,0.0573,
2#
0.0584
1.86
0.0572
0.0590
3#
0.126,0.125,0.132,0.124,0.126 0.127
2.37
0.127
1.01,1.00,1.03,1.02,1.00
1.01
1.28
1.00
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4#
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PMA-1000 TOF(Time of flight )mass spectrometry Characteristic of PMA
Oxygen , nitrogen , hydrogen, argon, helium can be
determined at the same time
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Summary
1.A determination method of carbon and sulfur in recarburiser
was established by tube furnace -infrared absorption
method .
2.A determination method of nitrogen in recarburiser was
established by Pulse melting -inert gas protection - thermal
conductivity method
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3. Through the precision, recovery, comparing with the PMA.
The results indicates that the two kinds of instruments
have a good performance.
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Acknowledgement
Thanks the sample provider,Yuzhong ferroalloy
CO.,LTD
Thank my colleague Hongxia Hou for PMA-1000
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Email:guofeifei@ncschina.com
CO., website: www.ncschina.com
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