The use of muffle furnace and precautions when testing ash
The muffle furnace is a general heating device. Usually also called box furnace.
The muffle furnace belongs to the periodic operation type, and is used for element analysis and determination in laboratories, industrial and mining enterprises, and scientific research units, as well as heating for heat treatment such as quenching, annealing, and tempering of general small steel parts. The high-temperature muffle furnace can also be used for sintering of metals and ceramics. , dissolution, analysis and other high temperature heating.
Matters needing attention during ashing:
(1) The sample in the porcelain boat should be flattened, and the thickness of the sample should not be too large;
(2) During ashing, the furnace door can be opened, and the porcelain boat containing the sample on the heat-resistant plate is slowly pushed into the furnace mouth of the box-shaped high-temperature electric furnace. First, the sample in the porcelain boat is slowly ashed and smokes. After a few minutes, when the sample no longer emits smoke, slowly push the porcelain boat into the hot part in the high-temperature furnace, close the furnace door and burn the sample at 815±15. If a coal sample catches fire and deflagrates during the ashing process, the coal sample is invalid and must be weighed and ashed again.
(3) The heating furnace should have a chimney or ventilation holes, so that the coal samples can remove the combustion products and maintain the circulation of air during the burning process.
(4) The control system of the high temperature furnace must indicate accurately. The temperature rise capability of the high-temperature furnace must meet the requirements for determining ash content.
(5) The ashing time should be able to ensure that the sample is completely ashed at a temperature of 815±15, but it is also unfavorable to prolong the ashing time arbitrarily.