Muffle furnace calcination use principle and precautions - Database & Sql Blog Articles

Photocoupler

Calcination: A heat treatment in air or an inert gas stream at a certain temperature, called calcination or calcination, is a thermal dissociation or crystal transformation process of a natural compound or an artificial compound; at this time, the compound is thermally dissociated into a simpler compound. Or a crystal transformation occurs. Thermal dissociation of carbonate is referred to as baking. Calcination can be used to directly process mineral raw materials to suit subsequent process requirements, and chemical concentrates can be used to prepare chemical concentrates to meet user requirements.

The main physical and chemical changes that occur during the calcination process are:

(1) Thermal decomposition. Removal of chemically bound water, CO2, NOx and other volatile impurities, at higher temperatures, the oxide may also react with the solid phase to form an active compound state;

(2) Recrystallization, which can obtain a certain crystal shape, crystal size, pore structure and specific surface;

(3) The crystallites are appropriately sintered to improve mechanical strength. The main factors affecting the calcination process: calcination temperature, gas phase composition, thermal stability of the compound, and the like. Therefore, according to various compounds (such as carbonates, oxides, hydroxide monosulfides, oxyacid salts, etc.), the thermal stability is different, and the control of the calcination temperature and the gas phase composition can be used to selectively change certain compounds. The composition or the transformation of the crystal form, and then treated by the corresponding method, can achieve the purpose of removing impurities and separating and enriching the useful group.

Muffle furnace: translated by English Mufflefurnace. Muffle is the meaning of the package, furnace is the meaning of the furnace, the furnace. The general name of muffle furnace in China is as follows: electric furnace, electric resistance furnace, Maofu furnace, Mafu furnace.

The muffle furnace is a general-purpose heating device. It can be divided into box-type furnace-type furnaces according to the shape of the appearance.

The muffle furnace is divided into domestic muffle furnace and imported muffle furnace according to nationality.

According to the heating element, there are: electric furnace muffle furnace, silicon carbon rod muffle furnace, silicon molybdenum rod muffle furnace;

According to the rated temperature, it is generally divided into: 1000 degree muffle furnace, 1200 degree muffle furnace, 1300 degree muffle furnace, 1600 degree muffle furnace, 1700 degree muffle furnace.

According to the controller, there are the following types: pointer table, ordinary digital display table, PID adjustment control table, program control table;

According to the insulation materials, there are two types: ordinary refractory bricks and ceramic fibers.

Muffle furnace cycle operation type, for laboratory, industrial and mining enterprises, scientific research units for elemental analysis and determination of general small steel parts quenching, annealing, tempering and other heat treatment, high temperature Mafu furnace can also be used for metal, ceramic sintering, dissolution , analysis and other high temperature heating

Features:

(1) This product has a wide range of applications and can be used for weight analysis: ash determination of organic matter and coal.

(2) The heating element is placed on the inner four walls to accelerate the rise of temperature and uniform heating.

(3) The heating element is made of special refractory material and completely concealed in the inner wall to avoid contact with corrosive gas, steam, etc., and prolong its service life.

(4) The muffle furnace and the control part are separately arranged, so that the electronic temperature controller can accurately grasp the temperature even under a long period of operation.

(5) The outer shell of the muffle furnace is double-layered, and the circulation of air can keep the surface low temperature, so there is no need to worry about the phenomenon of burning people.

(6) The digital setting and display panel indicate the exact temperature.

Maintenance and precautions:

1. When the muffle furnace is used for the first time or after long-term deactivation, the oven must be carried out. The oven should be at room temperature 200 ° C for four hours. 200 ° C to 600 ° C for four hours. When using, the furnace temperature should not exceed the rated temperature to avoid burning the heating elements. It is forbidden to inject various liquids and easily soluble metals into the furnace. It is best to work at a temperature below 50 °C below the maximum temperature. At this time, the furnace has a long life.

2. The muffle furnace and controller must work in a location where the relative humidity does not exceed 85% and there is no conductive dust, explosive gas or corrosive gas. When a metal material such as grease is required to be heated, a large amount of volatile gas will affect and corrode the surface of the electric heating element to destroy and shorten the life. Therefore, when heating, it should be prevented and sealed in a timely manner or properly opened to eliminate.

3. The muffle controller should be limited to use in the ambient temperature range of 0-40 °C.

4. According to the technical requirements, regularly check whether the wiring of each electric furnace and controller is good, whether there is stuck or not when the indicator pointer moves, and use the potentiometer to check the instrument due to magnetic steel, demagnetization, wire drawing, and shrapnel. The increase in error caused by fatigue, balance damage, and the like.

5. Do not pull out the thermocouple at high temperatures to prevent the jacket from bursting.

6. Always keep the furnace clean and remove the oxides in the furnace in time.

Caution: Do not bake flammable or explosive materials in the furnace to avoid danger! It is also not allowed to heat volatile corrosive substances, otherwise it will affect its service life.