Muffle furnace calcination principle
Burning: at a certain temperature, air or inert gas for heat treatment, known as calcination or roasting
Calcined natural compounds or thermal dissociation of man-made compounds or crystalline transition process compound thermal dissociation is a component of a more simple compounds or shape changing. Thermal dissociation is called calcination of carbonates. Burning operation can be used directly for processing mineral raw materials for subsequent processing requirements, chemical mineral processing can also be used to manufacture chemical concentrate, meet the requirements of users of the products.
Calcination process of main physical and chemical changes that occur are: (1) thermal decomposition. Get rid of chemically combined water, volatile impurities such as CO2,NOx, high temperature, oxide can also occur by solid phase reaction and forming a combined form of activity (2), recrystallization, some Crystal, Crystal size, pore structure and surface, (3) appropriate-ceramics sintered to increase mechanical strength.
Main factors influencing the calcining process: burning temperature, gas composition, thermal stability of these compounds. According to various compounds (such as carbonates, oxides, hydroxides sulfides, oxygen-containing salts) the thermal stability is not the same, controlling burning temperature and gas composition, you can selectively change the composition or shape of certain compounds change, then use the appropriate method can be achieved to remove impurities and make useful set of separation and enrichment purposes.
Maintenance and precautions:
1. muffle furnace again after first use or long-term outages when used must be oven. Baking time should be room temperature 200 ° c for four hours. 200 c to 600 c for four hours. When in use, shall not exceed a maximum rated temperature of the temperature, so as not to burn down the heating element. Prohibits the perfusion fluids and soluble metal in the furnace, Mochifuku furnace best in less than the maximum temperature 50 ° c the following work, stove has a longer life expectancy.
2. muffle furnace and controller must be in the relative humidity less than 85, no conductive dusts, explosive gas or corrosive gas work. Any metals require heating, such as oil, a large number of volatile gases will influence corrosion and surface of the heating element, destruction and shortened life expectancy. Therefore, the heating should be timely prevention and sealing containers or appropriate holes be excluded.
3. muffle furnace controller should be limited to an ambient temperature of 0-40 degrees Celsius range.
4. in accordance with technical requirements, regularly check the electric wiring wiring for well, controllers, indicators during the pointer movement without stuck stuck using potentiometer proof instrument due to magnetic, demagnetization, up fatigue, balance, shrapnel damage caused errors.
5. thermocouple not suddenly pull out at high temperatures to prevent coat burst.
6. keeping a clean furnace, removing oxides in the furnace and the like.
Note: the furnace is not flammable, explosive materials for baking, avoid danger! Nor of volatile corrosion of heating material, otherwise it will affect its service life