ASTM D4422 Standard Test Method for Ash in Analysis of Petroleum Coke
6. Apparatus
6.1 Crucibles, low wide form glazed porcelain or platinum, 30-mL capacity.
6.2 Muffle Furnace, with temperature control between 700 and 750°C and equipped with a means to regulate air circulation.
6.3 Analytical Balance capable of weighing to 0.1 mg.
6.4 Drying Oven controlled at 110 +/- 5°C.
6.5 Desiccator.
7. Sample Preparation
7.1 Crush the laboratory sample to pass a 6.3-mm sieve. If the quantity exceeds 2.3 kg, divide the sample to obtain about 2.3 kg and crush this fraction to pass a 850-µm (No. 20) sieve. Further divide the sample to obtain a portion of approximately 200 g and crush to pass a 250-µm (No. 60) sieve. Divide again to obtain approximately 50 g and pulverize this fraction such that 95 % or more passes a 75-µm (No. 200) sieve. This is the analysis sample which is dried to constant weight at 110 +/- 5°C.
NOTE 1 - If the laboratory sample appears to be wet it must be air-dried prior to crushing to avoid caking.
NOTE 2 - Recommended practice for collecting samples and the equipment and procedures for crushing and dividing are described in Practices D346 and D2013.
8. Preparation of Apparatus
8.1 The muffle furnace, when initially set up, must be tested for adequate air circulation. The air flow is adequate if replicate samples do not produce a lower ash at higher air flow rates with the same furnace loading. Maintain air flow at the same level for subsequent analyses to ensure consistency in analytical technique.
