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The sulfur determination device consists of an air purifier, a controller, an incinerator, an electrolytic cell and a stirrer.
It is mainly used to determine the total sulfur content in coal, steel and various minerals. The preferred basic equipment.
Analysis principle
The coal sample is burned in the purified air flow under the high temperature condition of 1150 °C, and all the sulfur in the coal is removed and destroyed. It is decomposed by combustion and carried by the airflow into the electrolytic cell where it combines with water to form H2SO3 as it destroys the dynamic equilibrium of the original iodine-iodide ion pair in the electrolytic cell;
The device outputs power immediately. Iodine is generated by the electrolysis of potassium iodide solution to restore the original dynamic equilibrium represented by the coulometric titration in IOS214-1996.
The amount of current needed to restore the original dynamic equilibrium is directly related to the amount of burned and decomposed sulfur in the coal sample, which can be measured and calculated by the microprocessor. So we can determine the total sulfur content in coal.
The coal sample is burned in the cleaned air flow at a high temperature of 1150 °C, whereby various forms of sulfur in the coal are decomposed into SO2 and a small amount of SO3 and escape. The reaction is as follows:
Coal (organic matter) + O2→CO2 ↑+H2O+SO2 ↑+CI2 ↑+...
4FeS2+11O2→2Fe2O3 +8SO2 ↑
2ΜSO4→2MO+2SO2 ↑+O2 ↑ (M refers to metal elements)
2SO2+O2→ 2SO3 ↑
The generated SO2 and a small amount of SO3 are brought into the electrolysis cell by the air flow and combine with water to form H2SO3 and a small amount of H2SO4, which destroy the equipotential bondingof iodine-potassium iodide pair, and the device instantly dissolves potassium iodide and generates iodine through automatic electrolysis to titrate H2SO3 through oxidation.
The reaction formula is:
anode;2I-–2e→I2
cathode;2H++ 2e → H2
The reaction formula of the iodine oxidation H2SO3 is: I2+H2SO3+H2O→2I-+H2SO4+2H+
The generated iodine consumption Through electrolysis, the current collected by the controller and the corresponding milligrams of sulfur calculated. The total sulfur content (%) in the coal can be calculated by dividing the milligrams of sulfur contained in the coal sample by the weight (mg) of the coal sample.
Principle of the method
According to the principle of coulometric titration, the coal sample is put into the purified air stream under the high temperature condition 1150 ℃ and the effect of the catalyst. During combustion, all forms of sulfur are burned into charcoal, and into SO2 and a littleAmount S decomposesO3 gas;
The cleaned air stream is fed into the electrolytic cell to produce H2SO3 or a small amount of H2SO4. H2SO3 is immediately oxidized to H2SO4 by I2 (Br2) in the electrolyte. The result is: The I2(Br2) of the system decreases while the I(Br) increases;
The equilibrium state of the electrolyte is destroyed, the potential between the indicating electrodes increases, the instrument automatically judges the start of electrolysis and controls the magnitude and time of the corresponding electrolyte current, so that the I2 (Br2) generated at the electrolytic electrode is equal to the amount consumed by the H2SO3 reaction, so that the electrolyte rebalances status and repeats the process until the end of the test.
The instrument calculates the total sulfur content in the sample according to Faraday's law of electrolysis based on the integration of the Str consumed by the electrolysis to produce I2 (Br2).Oms.
