Muffle furnace, also known as box type furnace, easy to maintain, the furnace is equipped with a controlled chimney. It can be used in electric power, paper, petrochemical, cement, agriculture and animal husbandry, medical scientific research, teaching and other industries and departments. At the same time, it is also suitable for chemical analysis of coal, coking products and chemical raw materials.
Muffle furnace is widely used in coal ash, volatile matter, total sulfur determination and coal ash composition analysis. It is one of the commonly used equipment for coal quality analysis.
Coal
Ceramic
Building Material
Medicine
Structure of Muffle Furnace
Muffle furnace from the application is mainly divided into two major parts: furnace body and controller.
The furnace body consists of shell, insulation layer, furnace chamber and heating element.
1, The shell is welded by angle steel and steel plate, for easy access, the rear of the shell made easy to remove the small door.
2, Insulation layer to play a role in insulation and insulation. Operating temperature below 950 degrees in the muffle furnace, with electric heating wire as a heating element, with light insulation brick or aluminum silicate cotton insulation; working temperature below 1300 degrees in the high-temperature furnace, with silicon-carbon rod as a heating element, with refractory bricks as insulation materials.
3,The furnace chamber is generally rectangular.
4, Electric wire high-temperature furnace chamber with a very small expansion coefficient of high corundum made, and for the double structure with holes; silicon-carbon rod high-temperature furnace with high alumina brick built into a rectangular chamber. Electric heating wire to do the heating element, wear in the chamber of the through-hole, from the chamber can not be seen; silicon-carbon rod high-temperature furnace heating element is a silicon-carbon rod, exposed in the chamber, so the door is equipped with a travel switch, when the door is opened automatically cut off the power to ensure safety.
Operating rules for determination of ash and volatile in Muffle furnace
【 Ash firing】
1. Slow Ashing method:
(1)The measured sample is taken out from the dryer in turn, (do not reverse the sample) into the constant temperature zone of the Muffle furnace whose temperature does not exceed 100 °C. Close the furnace door and leave a gap of about 15 mm on the furnace door, and slowly rise to 500 °C in no less than 30 minutes, and maintain at this temperature for 30 min. Continue to heat up to (815°±10℃) and burn at this temperature for 1h.
(2)Take out the ash dish from the furnace in turn, put it on the heat-resistant porcelain plate or asbestos plate, cool it in the air for about 5 min. Then move it into the drying dish, cool it to room temperature, and then send it to the balance room for weighing.
(3) For inspection burning, 20 min each time, until the mass change after two consecutive burns is no more than 0.0010g, based on the quality of the last burning.
2. Rapid ashing method
(1)Remove the dishes (the first ash dish with coal sample) from the dryer, open the Muffle furnace door that is pre-heated to 815 °C. Place the ash dish in turn at the low temperature of the furnace door, and slowly push into the Muffle furnace. Wait 5–10 minutes after the coal sample is no longer smoking, and push the remaining ash dishes into the hot section of the furnace in sequence at a speed of no more than 2 cm per minute (if the coal sample explodes on fire, the sample will be discarded.
(2) Close the furnace door and burn at (815±10) ℃ for 40 min
(3) Take out the ash dish from the furnace, put it in the air to cool for about 5 minutes, move it into the dryer to cool it to room temperature, and send it into the balance room to "weigh".
For inspection burning, 20 min each time until the mass change after two consecutive burns is no more than 0.0010g, the mass after the last burning as the basis for calculation. If the inspection burn is unstable, it should be redetermined by slow ashing method. Note: The coke is burned for 2 hours.
【 The firing of volatile compounds】
(1) Take out the crucible frame with the sample from the dryer and place it on the Muffle hearth, which is heated to 920℃ in advance.
(2) Open the furnace door and quickly put the crucible and the sample of chromium wire rack into the constant temperature area, immediately close the furnace door and time, accurate heating for 7 min
(3) The crucible and shelf are put into the furnace temperature is required to recover to (900±10) ℃ within 3 minutes, and then remain at (900±10) ℃, otherwise the sample is scrapped.
(4) Quickly take out the crucible from the furnace, cool it in the air for about 5 min, move it into the dryer, cool it to room temperature, and send it into the balance room.
(5) Put the crucible into the furnace and take out the crucible, do not shake off the crucible cover, once the sample is discarded.
(6) If there is only one sample, the crucible rack should be filled with empty crucible to ensure the constant temperature and ensure the accuracy of volatile data.
The difference between a muffle furnace and an oven
Muffle oven and oven are commonly used laboratory heating equipment, but their role and operation mode are different.
Muffle stoves are mainly used for high temperature experiments, usually reaching temperatures above 1000 °C. Muffle furnace generally uses electric heat or gas for heating, and has good temperature control performance. It can be used in fused glass, high temperature reaction, ceramic manufacturing and other experiments.
Ovens are typically used for low temperature drying and constant temperature insulation. It is mainly heated by electric heating, which can control the temperature between dozens of degrees Celsius and hundreds of degrees Celsius. Oven is widely used in chemistry, biology, food, medicine and other fields of experiment, such as drying, moisture determination, aseptic culture, etc.
LIB Environmental is one of the professional and credible manufacturers of climatic and environmental testing chambers in China. Equipped with a professional factory, we can offer you the most competitive price of Lab Muffle Furnace.
Now we have high quality Lab Muffle Furnace and other ovens for sale. As long as you have doubts about environmental test chamber, want to seek testing solutions, or you are interested in this machine, please feel free to contact us!
