CARBON AND SULPHUR SPECIES

Determining carbon and sulphur species can provide valuable information on mineralogy, metallurgy, and environmental issues pre and post project evaluation.

Accelerator material is added to a 0.2g sample. The inductive elements of the sample and accelerator couple with the high frequency field of the induction furnace. The pure oxygen environment and the heat generated by this coupling cause the sample to combust. During combustion, carbon-bearing elements are reduced, releasing the carbon, which immediately binds with the oxygen to form CO and CO2, the majority being CO2. A small amount of carbon monoxide is converted to carbon dioxide in the catalytic heater assembly. Sulphur-bearing elements are reduced, releasing sulphur, which binds with oxygen to form SO2. Carbon is measured as carbon dioxide in the IR cell as gases flow through the IR cells, and sulphur is measured as sulphur dioxide in the infrared cell. Both carbon dioxide and sulphur dioxide absorb IR energy at precise wavelengths within the IR spectrum. Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to carbon dioxide (CO2) or sulphur dioxide (SO2). The concentration of CO2 and SO2 are each detected as a reduction in the level of energy at the individual detectors. The analysis is performed using ELTRA Instruments.

AnalysisMethodReporting Limit
Total CIR0.01%
Total SIR0.01%

The C-Organic is calculated according to the following:

C-Organic = Total C – CCO2 – CGraphitic

Carbon analysis is performed by the absorption of IR energy which can be attributed only to carbon dioxide (CO2) which absorbs IR energy at a precise wavelength within the IR spectrum. The concentration of CO2 is detected as a reduction in the level of energy at the detector. It can be measured in either an inert atmosphere or an oxygen atmosphere (binding carbon species with the oxygen to form CO (converted to CO2 prior to detection) and CO2, the majority being CO2, and is measured as carbon dioxide in the IR cell as gases flow through the IR cells. Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to carbon dioxide (CO2). The concentration of CO2 is detected as a reduction in the level of energy at the detector. The Total C and CGraphitic analyses are performed using ELTRA Instruments. The descriptions of these methods are found in the website.

Reporting Limit
4F-C Organic (calc)0.5%

A 0.2g sample is reacted with hydrochloric acid in a filtering combustion crucible to remove carbonate carbon. Carbon analysis of the remaining residue (non-carbonate carbon) is performed by the absorption of IR energy which can be attributed only to carbon dioxide (CO2) which absorbs IR energy at a precise wavelength within the IR spectrum. The concentration of CO2 is detected as a reduction in the level of energy at the detector. It can be measured in either an inert atmosphere or an oxygen atmosphere (binding carbon species with the oxygen to form CO (converted to CO2 prior to detection) and CO2, the majority being CO2, and is measured as carbon dioxide in the IR cell as gases flow through the IR cells. Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to carbon dioxide (CO2). The concentration of CO2 is detected as a reduction in the level of energy at the detector. The analysis is performed using ELTRA Instruments.

Reporting Limit
4F-C Organic (non-carbonate carbon)0.02%

Accelerator material is added to a 0.2g sample. The inductive elements of the sample and accelerator couple with the high frequency field of the induction furnace. The pure oxygen environment and the heat generated by this coupling cause the sample to combust. During combustion, carbon-bearing elements are reduced, releasing the carbon, which immediately binds with the oxygen to form CO and CO2, the majority being CO2. A small amount of carbon monoxide is converted to carbon dioxide in the catalytic heater assembly. Carbon is measured as carbon dioxide in the IR cell as gases flow through the IR cells. Carbon dioxide absorbs IR energy at a precise wavelength within the IR spectrum. Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to carbon dioxide (CO2). The concentration of CO2 is detected as a reduction in the level of energy at the detector. The analysis is performed using ELTRA Instruments.

AnalysisMethodReporting Limit
4F-C TotalIR0.01%

A 0.5 g sample is subjected to a multistage furnace treatment to remove all forms of carbon with the exception of graphitic carbon. Either a resistance or induction furnace is used for analysis. The inductive elements of the sample and accelerator couple with the high frequency field of the induction furnace. The pure oxygen environment and the heat generated by this coupling cause the sample to combust. During combustion, carbon-bearing elements are reduced, releasing the carbon, which immediately binds with the oxygen to form CO and CO2, the majority being CO2. Carbon is measured as carbon dioxide in the IR cell as gases flow through the IR cells. Carbon dioxide absorbs IR energy at a precise wavelength within the IR spectrum. Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to carbon dioxide (CO2). The concentration of CO2 is detected as a reduction in the level of energy at the detector. The analysis is performed using ELTRA Instruments.

AnalysisMethodReporting Limit
4F-C GraphiticIR0.05%

A sample 0.2 g in size is thermally decomposed in a resistance furnace in a pure nitrogen environment at 1000 °C, using an ELTRA CW-800, directly releasing CO2. H2O is removed in a moisture trap prior to the detection of carbon dioxide in the IR cell. Carbon dioxide absorbs IR energy at a precise wavelength within the IR spectrum. Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to carbon dioxide (CO2). The concentration of CO2 is detected as a reduction in the level of energy at the detector. The Analysis is performed using ELTRA Instruments. The CaCO3 is calculated according to the following:
CaCO3 (calc) = Measured CO2 * (MW CaCO3 (100.089)/MW CO2 (44.010)

 

AnalysisMethodDetection Limit
CaCO3Infrared, Calc.0.02%

0.2 g sample is thermally decomposed in a resistance furnace in a pure nitrogen environment at 1000 °C, using an ELTRA instrument, directly releasing CO2. H2O is removed in a moisture trap prior to the detection of carbon dioxide in the IR cell. Carbon dioxide absorbs IR energy at a precise wavelength within the IR spectrum. Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to carbon dioxide (CO2). The concentration of CO2 is detected as a reduction in the level of energy at the detector.

AnalysisMethodDetection Limit
CO2Infrared0.01%

A 0.3g sample is thermally decomposed in a resistance furnace in a pure nitrogen environment at 1000 °C, using an ELTRA CW-800, directly releasing H,2O, which includes both H,2O- and H,2O+. H,2O absorbs IR energy at a precise wavelength within the IR spectrum. Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to water (H,2O). The concentration of H,2O is detected as a reduction in the level of energy at the detector. Total H is calculated from H,2O.

AnalysisMethodDetection Limit
Total HInfrared, Calc.0.01%

A 0.3g sample is thermally decomposed in a resistance furnace in a pure nitrogen environment at 1000 °C, using an ELTRA Instrument, directly releasing H2O, which includes both H2O- and H2O+. H2O absorbs IR energy at a precise wavelength within the IR spectrum. Energy from the IR source is absorbed as the gas passes through the cell; preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to water (H2O). The concentration of H2O is detected as a reduction in the level of energy at the detector.

AnalysisMethodDetection Limit
Total H2OInfrared0.1%

A 0.2 g sample is combusted in a resistance furnace at 1350°C, using a LECO CNS-2000. Combustion gases are collected in a 4.5-liter ballast tank and then flow to the detectors. Nitrogen in the form of N2 is detected by thermal conductivity detection.

AnalysisMethodDetection Limit
Total NThermal Conductivity0.01%

Accelerator material is added to a 0.2 g sample. The inductive elements of the sample and accelerator couple with the high frequency field of the induction furnace. The pure oxygen environment and the heat generated by this coupling cause the sample to combust. During combustion, sulphur-bearing elements are reduced, releasing sulphur, which binds with oxygen to form SO2. Sulphur is measured as sulphur dioxide in the infrared cell. ELTRA instruments are used for analysis.

A 0.2g sample is first combusted in a resistance furnace at 550 °C in a pure oxygen environment to remove sulphide sulphur, although this is dependent on mineralogy (see 4F – Sulphide method description and below from ASTM). A catalyst is added to the sample and the temperature of the resistance furnace is increased to 1450 °C. During combustion, sulphur-bearing elements are reduced, releasing sulphur, which binds with oxygen to form SO2. Sulphur is measured as a SO2 in the infrared cell. ELTRA instruments are used for analysis.
According to ASTM E1915 in regards to sulphate sulphur, “In the absence of sulphide forms of sulphur, total sulphur may be used to estimate the sulphate sulphur concentration. The pyrolysis residual sulphur may be the best estimate of sulphate sulphur, in the presence of barite, alunite, jarosites, since these sulphate forms are not dissolved by sodium carbonate and in the presence of orpiment and realgar, since these sulphide minerals are soluble in sodium carbonate. The sodium carbonate sulphur loss may be the best estimate of sulphate sulphur in the presence of metal sulphide minerals other than iron, which may not be lost by pyrolysis and the absence of barite, alunite, jarosites, orpiment and realgar. ”

AnalysisMethodDetection Limit
SO4Infrared0.3%

Sulphite sulphur is calculated from the sulphate sulphur.

SO3 = Measured SSO4 * 2.497137

AnalysisMethodDetection Limit
SO3Infrared, Calc.0.3%

Sulphide sulphur is calculated from the difference between measurements at 550 oC and 1450 oC using combustion/IR, pyrolysis loss sulphur as described in ASTM E1915.

An interpretation of the calculated sulphide value must be made in reference to the mineralogy of the sample.

According to ASTM E1915 in regards to sulphide sulphur, “In the absence of sulphate forms of sulphur, total sulphur may be used to estimate the sulphide sulphur concentration. The pyrolysis loss sulphur may be the best estimate of sulphide sulphur, particularly where the acid generation potential due to iron sulphides is desired. The nitric acid loss method may be appropriate where the sulphide forms are primarily pyrite and marcasite and pyrrhotite is absent, since pyrrhotite may react with acid. The sodium carbonate residual sulphur method is most appropriate where the concentrations of metal sulphide minerals in addition to iron are desired in the absence of barite, alunite, jarosites, orpiment and realgar.”

Sulphide S = Total S – Measured SSO4

H2O-(moisture) is determined gravimetrically using a 2 g sample heated in an oven at 105°C (Other temperatures may be used at special request). 0.3 g of the dried sample(from H2O-) is thermally decomposed in a resistance furnace in a pure nitrogen environment at 1000 °C (interstitial water, H2O+), using an ELTRA CW-800, directly releasing H2O. H2O absorbs IR energy at a precise wavelength within the IR spectrum. Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to water (H2O). The concentration of H2O is detected as a reduction in the level of energy at the detector.

AnalysisMethodDetection Limit
H2O +/-Infrared0.1%