Heat treatment furnace

Heat treatment kiln heat treatment magnesia charcoal brick, corundum block brick, phosphate bonded brick and other refractory products, discharge volatiles, make the binder further solidify, thus improve the strength of non-fired brick. The varieties treated in the low-temperature heat treatment kiln at 150~350℃ include magnesia carbon brick, tar magnesia dolomite brick, etc.; the varieties treated in the medium-temperature heat treatment kiln at 600℃ include corundum block brick and phosphate-bonded firebrick, etc.

Heat source of heat treatment kiln generally adopts hot flue gas or electric heating. The production mode of heat treatment kiln can be divided into two modes: continuous operation and intermittent operation. The continuous operation of heat treatment kiln is tunnel type, generally using hot flue gas heating. A preparation room is set up in front of the kiln to prevent gas escaping from the kiln when entering the kiln and play a role in stabilizing the thermal system. The air supply and exhaust system is equipped with automatic and manual regulating valves, which can flexibly control the air volume and temperature at each point in the kiln. The kiln is equipped with unique air supply measures to ensure the uniform temperature in the kiln. Heat source set up by using hot air generator, to make full use of heat to reduce energy consumption, using egr, the middle into hot air from the kiln, both before and after discharge, waste gas of recycled from the kiln, the exhaust fumes into the car side by the double pipe heat exchanger to return to the combustion chamber, the binder of volatile and harmful gas incineration, reduce environmental pollution.

The electric heating heat treatment kiln generally uses the milky white quartz far infrared tube heater or the resistance wire heating. The temperature in the kiln is generally 200~350℃, and the installed power is 150~300kW. Electric heating calcination kilns are mostly intermittent operations, and the operating temperature is mostly in the range of 400~700℃. The installed power varies greatly with product varieties and the requirements of temperature rising rate, which is mostly in the range of 250~500kW. The temperature of electric heating furnace for producing si3N4 bonded silicon carbide brick is about 1400℃. Take intermittent operation of low-temperature electric heat treatment kiln to treat magnesium carbon brick as an example, the technological process is as follows:

First of all, push the kiln car with the brick into the heat treatment kiln in turn, close the front and back kiln doors after filling, and then turn on the electric heating elements for heating, heat preservation and cooling process successively. At the same time, the volatile matter in the brick is discharged by the discharge pipe. After the heat treatment process is completed, open the front and rear kiln doors and push out the kiln car successively.

The low-temperature heat treatment kilns using hot flue gas all adopt tunnel type, the outer wall of the kilns is covered with steel plate, the inner layer is insulated with rock wool or lined with red brick, the top is covered with reinforced concrete, the upper layer is insulated, and electric kiln doors are installed at both ends of the kilns. Reflector aluminum plate is installed on the top of the electric heating kiln, and reflective aluminum plate and electric heating elements are installed on both sides of the wall. Exhaust gas outlet is set on the top wall (bellows are embedded on the top wall of the kiln when hot flue gas is used as heat source), which has simple structure, light type, good air tightness and heat insulation. Room type intermittent operation mode of electric heat treatment furnace temperature 600 ℃, to make the bottom of the kiln kiln car, similar drawer kiln, wicket, at one end of the medial wall and the inside of the wicket installation electric heating element, kiln outer wall plate, the inner with light brick, outer with refractory fiber felt, the lower bearing wall with clay brick, the kiln top use of lightweight castable, install a vent at the same time, this temperature measuring pressure hole. The temperature inside the kiln is automatically adjusted based on the temperature measuring point in the middle of the kiln roof.

The main features of the electric heating treatment kiln are simple structure, low cost, no smoke and noise, flexible operation, uniform kiln temperature, easy to control the thermal system, to ensure the quality of products. In recent years, the application of electric heating furnace is gradually increasing, mostly used in the heat treatment of magnesia carbon brick, longshuiou, skateboard and other products, but also used in the roasting of skateboard, longshuiou and silicon nitride and other special refractories.