Application of microwave high-temperature sintering roller kiln on vanadium nitride (silicon nitride manganese)


  Microwave sintering technology is a kind of new science and technology, featured with high efficiency, energy saving, environmental protection and control agile,and used widely in agriculture and industry and high-tech field,and also formed into a new industry . Hunan Thersun Thermal Energy Technology Co., Ltd. has adopted microwave pusher kiln high temperature sintering control technology in producing vanadium nitride in a company in Hubei.And built a vanadium nitride automatic production line which produce a ton a day at the end of June, 2012 .At present,the equipment  operats in good condition and with stable product quality ,which has the advantages of short sintering time, high energy efficiency, high quality, automatic control production process, safety and pollution-free , short equipment maintenance time , on-line changing wearing parts and etc. to produce vanadium nitride.
1Principle of microwave heating
   Substance can be divided into conductor, semiconductor ,insulator. Insulator also named dielectric material, dielectric material consists of polar molecules and nonpolar molecule. Microwave is a high frequency electromagnetic wave which the frequency is between 300 MHZ and 300000 MHZ, the wave length is 1.01 m . These dielectric material which is made up of polar molecules and non-polar molecules under the action of high frequency electromagnetic field, the polar molecule will in accordance with the state to the polarity of array orientation from the random distribution of the electric field, producing intense friction and making heat. In this microscomic process, microwave energy can be transfer into heat in medium medium ,which can raise the temperature in the macroscopic view, this is the basic principle of microwave heating. Microwave heating is the dielectric material which losses itself electric energy to heat ,for conductive metal materials, the waves can't reflect through people internal part, metal materials cannot absorb microwave.
 2.The difference of heating between microwave sintering furnace and the traditional resistance furnace
  There are essential differences between vanadium nitride microwave sintering furnace and the traditional vanadium nitride resistance sintering furnace in heating The ordinary vanadium nitride resistance sintering furnace using traditional radiation conduction heating method which is to rely on the heating element contacts heat conduction and radiation through convection to deliver the heated objects and enables it to achieve a certain temperature,the heat transfer from within outward, has long sintering time and big energy loss. However, the heating method of microwave sintering furnace is according to the absorption of material to microwave and the coupling of microwave field or magnetic field, then microwave energy can be changed to heating energy. The heating method is that heating the object from the interior, it has short heating time, small energy consumption , high material density, high rate of products.
3.The advantages of the industrial application of microwave high-temperature sintering roller kiln on vanadium nitride (silicon nitride manganese)
3. 1. Easy to operate and control
  According to the control principle of microwave sintering , we can find that the microwave sintering equipment with strong integration control system , simple operation and convenient maintenance.You can just adjust the power control knob to control temperature .Based on vanadium nitride production process requirement, we can amend the computer program in time which is easy to automatic production control.

3.2 Efficient ,energy saving and high density
  Microwave coupling with material directly lead to material’s whole heating.Microwave can be absorbed by material directly then converted into heat energy .It has high energy efficiency, can save energy over 30% comparing to conventional sintering. Microwave sintering with fast heating speed, short sintering time which make the material internal thermal stress reduce, thus can reduce the cracking and deformation tendency and make high product density.

3. 3 Microwave generator with special isolator which may realize the magnetron ‘s online replacement.It ensure microwave leakage not overweight and no damage to human .The microwave leakage < 0.5 mw/cm2 (gb < 5 mw/cm2), and can change quickly.
3.4 The insulation material of microwave equipment are made of special material which has its own patent, be modular assembly. It can greatly shorten the time of equipment maintenance (general maintenance time is not more than one week).
4. The improvement in practical application.
   When the sintering temperature of vanadium nitride up to about 1200°C , nitrogen vanadium alloy can generate. At that time, the absorb ability of microwave decreasing and then reflect microwave.If using our own patent----- the technology of microwave/electric hybrid heating temperature pusher kiln, the energy-saving effect will greatly improved .
5. The pictures of industrial application 
5.1 Microwave high-temperature pusher kiln
5.2 Microwave high-temperature pusher kiln sintering vanadium nitride
5.3 Microwave high-temperature pusher kiln electric control room