China JKR50 Clay Brick making machine supplier manufacturers - Yingfeng Machinery

The reasons for the broken clay brick products and the prevention methods are briefly analyzed and explained here:

 1. Making billet mud

    When the composition and properties of the slush are inappropriate, the internal structure of the slug is not too dense, and it lacks flexibility and strength. For example, the combination of aggregate and fine material is unreasonable; too many materials with poor toughness are blended; lack of proper aging, etc.

    For some enterprises that use clay or similar materials as raw materials, due to the lack of proper aggregates in the mud, the number of broken bricks is generally large, such as: various types of clay, river silt, and waste from aluminum smelting - Red mud and other materials. Some hard shale, coal gangue, and slag materials can be added to increase the proportion of aggregates. From the practical and economical point of view, the mixing amount is between 15% and 40%. This is not only beneficial for reducing broken bricks, but also for relieving drying cracks and speeding up drying. The internal combustion material of some enterprises - fly ash is mixed with a large amount, which not only makes the compressive and flexural strength of the briquette worse, but also the bricks are easily softened and deformed when the fire temperature is high in the roasting stage. At one point, the strength of the product will become very poor. The mud of some enterprises is affected by equipment or human factors, and it cannot be fully digested and homogenized. When the mud material enters the extruder in the state of being sandwiched, the compactness and flexibility of the interior are greatly reduced, so that the compressive and flexural strength of the green body is reduced to varying degrees.

2. Extrusion

    Excessive moisture content of the block during extrusion, or the lack of performance or failure of the extruder itself, as well as the ultra-high stacking of the blanks, etc., can also lead to an increase in the brick breakage rate.

    On rainy and rainy days, the precipitation mud is exposed to rain, which increases the moisture content. Sometimes, when no more moisture is added during extrusion, the moisture content of the compact will be extremely high. Control the amount of water added even when extruding normally. In some enterprises, the model of the brick extruder is too small or the performance is too poor, which does not match the number of layers in the blank stack. Or the vacuum, stirring knife and other systems of the extrusion brick machine have malfunctioned. All of these situations can lead to broken bricks.

3. Kiln car

    Problems with the upper plane of the kiln car can also lead to an increase in the rate of broken bricks. When the upper plane is uneven, the support point of the billet at the bottom layer of the billet will be different, and the unreal part will be broken by the heavy pressure of the upper billet. In addition, when the roasting kiln runs faster, the hot and hot empty kiln car will be stacked with wet briquettes in the future and placed to cool down. The drying rate in the middle and upper part of the block is not in the synchronous stage, and the broken brick is produced. Some enterprises have adopted methods such as extending the idle time of kiln cars, forced cooling by fans or spraying an appropriate amount of water, etc., to alleviate such problems.

 4. Blank stack

    In addition to being convenient for drying and baking, a good billet structure should also have the ability to reduce or eliminate broken bricks.

    When stacking, strive to be vertical up and down, the force area between the upper and lower layers of the block should be large and evenly distributed, and the contact point should be smooth and stable. When manually stacking the blanks, the vertical and horizontal pulling blanks on the upper part of the blank stack are easily broken objects. During operation, they can be stacked on the upper 2-3 layers to reduce the weight of the upper blanks on them. As long as the structure of the blank stack is reasonable during mechanical stacking, the number of broken bricks in most cases is lower than that of manual stacking. The stability and firmness of the blank stack are also better determined.

5. Track and ferry

    When the track is laid, the gap distance between the rail and the rail should be reasonable, and the three types of high temperature, low temperature and normal temperature should be treated differently. In the billet making workshop and the front end of the drying kiln, the gap between the track is smaller because it is close to the normal temperature. When the gap is still more than 1.5 cm after the thermal expansion in summer, the bumpy shaking of the wet billet car will cause some billets. break. When the wet billet car is loaded or pushed down on the ferry car, the gap between the two rails is too large or uneven, or the billet is pulled or stopped suddenly, etc., which will cause some billets to break.

6. Dry

    Because the heating and moisture exhaust systems of drying kilns in various enterprises are complicated and varied, the operating conditions are also uneven.

    When the briquette is heated too early and too violently in the early drying stage, it is quickly forced to heat up, and then softens and deteriorates in strength. Even if there is no collapse of the blank stack, the brick breakage rate is relatively high. In this regard, it is necessary to delay the heat transfer time and reduce the amount of heat transfer, as well as reduce the temperature of the heat transfer, so that the green body is heated and dehydrated in a gradient manner.

    When the phenomenon of moisture regain occurs, the temperature is low in winter and spring, and the low temperature (0-18°C) compact is eroded by the surrounding hot and humid gas, and the gas condenses into dewdrops and distributes on the local compacts. It gradually penetrates into the interior, thereby destroying the original strength of the green body, causing the block to break in light, and causing the collapse of the stack in serious cases.

7. Roasting

    When the billet is loaded into the roasting kiln, there are certain requirements for the moisture content. When it is greater than 10%, it may cause the collapse of the billet in the kiln. Even if it does not collapse, it will react violently when subjected to high temperature. This can lead to poor preheating and breakage of wet briquettes, or even explode into shards. Through the investigation of many brick factories that are prone to bursting in East China, Central Plains and Northwest China, most of them are caused by the following reasons: (1) The moisture content of the briquette entering the kiln is too high, and the moisture should be controlled within 6%. It is beneficial to control bursting, increase roasting speed, improve product quality and reduce energy consumption. (2) The slime material for making the billet is too fine to make the billet water permeable and air permeability weakened. After the billet is heated up in the preheating zone in the kiln, some of the internal substances will be converted into air pressure. When this internal expansion pressure exceeds the billet When the tolerance level of the body is increased, it will cause a slow or instantaneous release, resulting in the fragmentation of the body into several or more than a dozen pieces, such as: the water is converted into water vapor; the volatilization of molecules such as hydrogen and nitrogen in the internal combustion can cause explosion. Granular materials such as hard shale, coal gangue and slag can be mixed into the mud to increase the air permeability of the briquette, thereby reducing or eliminating the accumulation of pressurized gas. (3) When the internal structure of the roasting kiln or the stacking of the billets is defective, it will also cause the bursting of the billets, such as: the gap between the kiln and the stack body is too large, or the density in the middle and lower parts of the stack body is large, and the longitudinal fire path Improper size and so on make too much high-temperature flue gas prematurely and focus on roasting part of the stack, causing the briquette to heat up rapidly and burst. (4) The total length of some kilns is too short or the position of the firing belt is placed in the front, or the frequency of feeding billets into the kiln is too high during the production operation, which will aggravate the bursting of the billets. (5) The way to use the wind to lift the gate should also be based on the principle of making full use of thermal energy and gradually preheating the briquette. The commonly used gate types are trapezoidal and bridge, which should be used according to the situation.

    No matter what the reason is, when the firing degree is too high, the brick body will be deformed and broken by the heavy pressure of the upper brick after softening. It is necessary to control the over-mixing of internal combustion; timely and accurately adjust the local ultra-high fire temperature; make a reasonable billet structure and layout; Work hard on the quantity and so on.