Recognize a Good Type of Coal with Coal Quality Test
To find out whether the coal material is good or bad, a coal quality test is needed. Because the quality of the mining goods will affect its use and selling price.
In this test there are several parameters that are used as benchmarks, such as total moisture, proximate analysis, ultimate analysis, total sulfur, calorific value, and Hardgrove Grindability Index (HGI). Here’s the explanation.
Coal Quality Test Process Through 6 Parameters
Testing is conducted to determine the content and quality so that it can be determined the need for its use. In this case the parameters for the test are as follows:
1. Total Moisture
Total moisture in coal will depend on:
- The rating: The higher the rating, the smaller the porosity of the material so that it is denser.
- Measurement distribution or measurement of particle size: If the particles are getting smaller, the surface area is bigger. The value of the measurement will directly affect the level of surface moisture.
- Conditions at the time of sampling: Including the size of the sample taken is too large or too small.
2. Proximate Analysis
The next parameter to test the quality of coal is to determine the amount of air dried moisture, ash content, and volatile matter.
- Moisture or moisture content: an analysis that is divided into free moisture and inherent moisture. The two are then added together to become the total moisture which is influenced by the amount of primary air usage.
- Ash content or ash content: Measures the ash content in the material from outside because coal does not contain ash in it.
- Volatile matter or volatile matter: A test by heating the material to a certain temperature and seeing at what temperature evaporation occurs.
3. Ultimate Analysis
That is a test conducted to determine the amount of carbon, hydrogen, oxygen, and sulfur in chunks. Usually, it is used to simplify the determination of reactions and heat balance calculations.
4. Total Sulfur
That is the coal quality test which is conducted to determine the sulfur content in it. Thermal and metallurgical sulfur will affect the combustion properties and product quality of steel.
In addition, the sulfur content will also affect the environment because of sulfur emissions that cause acid rain. The sulfur level will also affect the quality related to its commercial value. Sulfur is the limiting value of quality and price guarantees.
However, high sulfur content does not always make the selling price low. Because in some conditions the presence of sulfur really helps the performance of coal utilization so it doesn’t reduce its commercial price.
5. Calorific Value
That is the value of energy produced from burning coal. This value is expressed in MJ/Kg, Kcal/kg, and BTU/Ib, called the value in gross and net. This calorific value will depend on the rank of the coal, the higher the calorie, the higher the rank.
The calorific value is also affected by moisture and ash. The higher the two, the lower the caloric value.
6. Testing HGI Value
It is conducted to test the quality of coal on its physical properties which are expressed with a size of 200 mesh or 75 micro. The value of HGI or Hardgrove Grindability Index is determined from the organic constituents such as the type of maceral.
In general, the higher the coal rank, the lower the HGI value, except for bituminous with cooking properties in it (the HGI value is very high, reaching 100). The HGI value is also affected by the dilution of ash from mining which will increase it. In addition, the moisture content also has a large influence.
Each coal has its own rank and value. This value will affect its economic value. Before being sold, testing will usually be carried out to determine the value and content so that it is known how much the economic value is.
It is very important to have this test done and it should be done by a professional. Sucofindo can help you test coal to determine its content and value so that you can sell it at the right price. Sucofindo is a professional company that offers coal quality testing services.