Abstract No. 17

Determination of high carbon and high sulfur by the infrared

absorption method

GUO Fei-fei*1,2 ZHOU Yu-hong1,2 HU Xue-qiang1,2 HouHong-xia1,2

(1. China Iron & Steel Research Institute Group Beijing 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 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

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

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 . Four samples also were analyzed and it

was showed the relative standard deviation (RSD, n=3) was RSD_C%

<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 infrared absorption method copper concentrate high carbon and high sulfurCE

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Determination of carbon ,sulfur and nitrogen in recarburizer

Feifei GUO NCS Testing Technology CO.,LTD

May 21st, 2015

Outline

Background

Experiment

Results

Acknowledgement CETA

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Background

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.

Application

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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.

But because of the price and the different manufacturing techniques,some elements content need to be determined in order to ensure recarburizer meeting requirements.

Element Methods

Carbon Combustion - neutralization method, coulometric method

Sulfur Gravimetric method, Combustion titrimetric method

Nitrogen None

Why our methods?

Our methods are quick,convenient and less pollution.

For the above methods,analysis time is long,many chemical reagents are used. CETA

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Experiment

Instruments

N-3000 Pulse melting -inert gas protection -

thermal conductivity method

Carbon Sulfur Nitrogen

CS-2600 Resistance furnace combustion -

infrared absorption method

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Standard samples

Sample No. Material Carbon Sulfur Nitrogen

The spectrum pure

graphite 99.99% --- ---

GSB06-2103-2007

coal 90.26% 0.20% 0.56%

GBW11126a coal 80.03% 0.26% 0.25%

GSB06-2106-2007

coal 81.45% 0.40% 1.31%

GSB06-2111-2007 coal 79.02% 0.58% 1.03%

Composition and structure of the recarburizer and graphite or coal is very close.

Determination of carbon and sulfur in recarburizer by CS-2600

Method Optimization

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Choice of the temperature

Temperature /

Carbon Sulfur

Found w /%Average w /%

RSD% Found w /%

Average w /%

RSD%

900 97.73 --- --- 0.2473 --- ---

1000 98.04 --- --- 0.2571 --- ---

1100 97.93 --- --- 0.3008 --- ---

120097.43,97.13,

97.8197.79 0.36 0.3702,0.3776,

0.36690.3715

1.48

130097.56,97.95,

97.7097.74 0.21

0.3681,0.3765, 0.3797

0.3748 1.59

1300 was selected in this experiment.

Referance for YB/T 1430-1997,weight of recarburizer was 0.2g and grain was less than 0.2mm .

Releasing curve

voltage

time

Carbon

Sulfur

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Calibration curve

Carbon

Sulfur

R(linear correlation coefficient)

Method Optimization

Determination of nitrogen in recarburizer by N-3000

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Calibration curveNitrogen

Be dried about 1hour in oven at 105 .

The choice of sample grain: 120 mesh was selected.

Sample -grain Found w/% RSD /%1#-80 mesh 0.623,0.536,0.610,0.560,0.568 7.83

1#-120mesh 0.613,0.583,0.576 0.606,0.588 2.37

1#-150mesh 0.578,0.602,0.595,0.596,0.603 2.41

Sample preparation

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Chioce of analysis power We selected 4.5kW.

Analysis power /kW Found w/%

Average w/%

RSD /%

4 0.5062,0.4987,0.4898,0.5124,0.4765 0.4967 2.54%

4.5 0.5768,0.5576,0.5612,0.5433,0.5569 0.5591 1.92%

5 0.5678,0.5431,0.5529,0.5376,0.5628 0.5528 2.06%

Chioce of flux We selected nickel bag.

Nickel foil (tailing) Nickle bag

Results

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Resistance furnace combustion -infrared absorption method Carbon

Sample No.Found w /% Average w /% RSD%

1# 99.85,99.72,100.00 99.86 0.172# 97.68,97.69,97.43 97.6 0.153# 92.97,93.73,93.72 93.47 0.474# 76.10,76.46,76.09 76.22 0.27

Sample No.Carbon of

recarburiser/g Added/g Total found /gRecovery rate

2#

0.2002 0.1801 0.3787 99.110.1966 0.1820 0.3784 99.890.1926 0.1805 0.3675 96.90

4#

0.1529 0.1816 0.3528 109.770.1511 0.1821 0.3488 108.570.1572 0.1812 0.3577 110.65

Precision and Accuracy of Carbon

Sample No.Sulfur of

recarburiser /g

Added/g Total found /gRecovery rate

2#0.00078 0.00040 0.00117 97.500.00074 0.00041 0.00118 107.320.00074 0.00040 0.00115 102.50

4#0.00028 0.00040 0.00068 100.250.00028 0.00040 0.00069 101.910.00027 0.00041 0.00072 109.43

Resistance furnace combustion -infrared absorption method Sulfur

Sample No.Found w /% Average w /% RSD%

1# ND ND ND2# 0.368,0.376,0.380 0.375 1.593# 0.199,0.191,0.200 0.197 2.354# 0.138,0.141,0.135 0.138 2.11

Precision and Accuracy of Sulfur

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Sample No.

N-3000-Pulse melting -inert gas protection - thermal conductivity method

Nitrogen PMA-1000Found w/%

Average w/%

RSD%

1# 0.577,0.558,0.561,0.543,0.557 0.559 1.92 0.554

2#0.0572,0.0595,0.0591,0.0573,

0.05900.0584 1.86 0.0572

3# 0.126,0.125,0.132,0.124,0.126 0.127 2.37 0.127

4# 1.01,1.00,1.03,1.02,1.00 1.01 1.28 1.00

Precision and Accuracy of Nitrogen

PMA-1000

Characteristic of PMA Oxygen , nitrogen , hydrogen, argon, helium can be determined at the same time

TOF(Time of flight )mass spectrometry

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Summary1.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

3. Through the precision, recovery, comparing with the PMA. The results indicates that the two kinds of instruments have a good performance.

Thanks the sample provider,Yuzhong ferroalloy CO.,LTD

Thank my colleague Hongxia Hou for PMA-1000

Email:guofeifei@ncschina.com

CO., website: www.ncschina.com

Acknowledgement

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