The Minister of Natural Resources and Environment issued Circular 18/2024/TT-BTNMT on October 1, 2024, regarding the economic-technical norms for the determination of the content of certain chemical elements using chemical coal analysis methods, smelting methods, and inductively coupled plasma optical emission spectrometry (ICP-OES).
The contents of work in determining the gross calorific value of coal according to the Economic - Technical Norm for determining the content of certain chemical elements by coal chemical analysis methods, fusion methods, and inductively coupled plasma optical emission spectrometry (ICP-OES) methods issued with Circular 18/2024/TT-BTNMT are as follows:
* Preparation Work
- Sample Preparation:
+ Receive samples (samples have been processed: ground and sieved through a 212 µm mesh, in some cases, the maximum particle size of 250 μm may be a🐬cceptable for medium and low metamorphic coal types);
+꧅ Samples are thoroughly mixed to achieve moisture content balanced with laboratory moisture content. Moisture content needs to be determined on samples that have been pre-weighed a few hours before determining the🌊 heat value, or samples are kept in a small, effective sealed container until moisture content analysis, allowing for appropriate correction of moisture content in the analytical sample;
+ The coal sample used for the float and sink test may contain halogen compounds, which can affect the determination of the gross calorific value due to the heat of ac🌞id formation processes. It is necessary to remove residue traces before proceeding with the determination.
- Machine Preparation;
- Equipment and Tool Preparation;
- Chemical and Reagent Preparation.
* Conducting Calorimetric Measurement
- Preparing the bomb for measurement;
- Assemble calorimeter;
- Combustion reaction 🌳and temperature measurement;
- Analyzing combustion products;
- Correcting temperature increase;
- Standard temperature;
- Calibration: using a standard samp🔜le to check the accuracy of the machine.
* Analysis Results
- Presentation of results;
- Checking analysis results;
- Pro𒅌cessing analysis result data, preserving analysis results, retaining analysis samples until anal🌳ysis results are delivered;
- Minor repairs, maintenance, and calibratౠion of instruments and equipment.
* Delivery of Analysis Rꩵesults and Management of Analysis Re🔴sults
More details can be found in Circular 18/2024/TT-BTNMT, which comes🎃 into fo🧸rce in Vietnam from November 15, 2024.
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