china Henan Ruiyao Intelligent Environmental Protection Co., Ltd Company News

The Vice Chairman of the Standing Committee of the Provincial People’s Congress and the Secretary of the Party Committee of the China Environmental Protection Industry Association visited the Asia New Exhibition booth. They encouraged local enterprises in Henan to firmly grasp technological innovation, enhance industry market competitiveness, and support innovation-driven high-quality development.      

We all know that during the process of extrusion, cutting and pushing of the clay strips by the brick machine, brick slag will adhere to the cut hollow brick blanks. If these brick blanks are loaded on the kiln car without being treated with brick slag, it will have an adverse effect on the quality of the bricks fired. After the hollow brick clay strips are cut by the steel wire, brick slag will adhere to the holes of the brick blanks. These brick slags stick to the holes and the edges of the brick blanks, which reduces the porosity of the hollow bricks or causes the edges of the brick blanks to be not smooth. During the drying and baking process, the edges of the hollow brick holes are adhered to brick slag, which blocks the air from flowing into the holes, slowing down the drying speed of the brick blanks.  If the speed of the car is fast, the blanks cannot be completely dried, which seriously affects the quality of the blanks. During the baking process of the blanks, since the oxidation of carbon also requires oxygen to enter the blanks for reaction, the presence of brick slag causes oxygen to react with brick slag first, delaying the time for oxygen to enter the holes, slowing down the baking reaction speed. Due to the incomplete oxidation reaction, the internal black core of the brick increases, affecting the internal stress and compressive and flexural strength of the brick, thus affecting the brick's progress to a higher level. Practice has proved that the reduction of brick slag can improve the quality and output of bricks.

The main reasons for condensation and even collapse are that the temperature of the green body is too low and the humidity of the drying medium is too high (reaching saturation). The preventive measures are: The raw materials are prepared by heat to increase the temperature of the green body so that the green body temperature is slightly higher than the gas temperature at the inlet end.   Increase the dehumidification air volume and appropriately increase its temperature to keep the relative humidity of the exhaust gas at the dehumidification port at around 95% to prevent the gas from reaching saturation. However, the relative humidity of the exhaust gas should not be too low. When the relative humidity drops from 95% to 85%, the air volume needs to be increased by 15%~20% to discharge the same mass of water, and the heat taken away (lost) increases by 15%~20%. Reduce the moisture content of the molding to enhance the strength of the green body.

Strengthen raw material processing, reduce molding moisture, and improve the strength of the brick.   Increase the temperature of the brick. The relative humidity of the exhaust gas should be controlled at about 95%, not too high, to prevent condensation from forming when the brick enters the drying channel, which will hinder the discharge of moisture inside the brick. Then, the brick will suddenly encounter high temperature and low humidity gas, causing the brick to dehydrate rapidly and crack. Control the residual moisture of the brick after drying to about 6%, and put it into the kiln in time to prevent the brick from absorbing moisture from the outside and cracking due to low residual moisture. When the fan is temporarily stopped due to power outage or maintenance, the inlet and outlet doors and inspection ports should be opened to allow moisture to escape, so as to prevent the brick that has lost some moisture from absorbing moisture again in the drying channel and cracking.

The molding moisture is too high. The molding moisture of the green body should be reduced to improve the strength of the wet green body to avoid fracturing due to the wet green body being too soft. The plasticity index of the raw material is too low, and the green body strength is low, causing fracturing. Raw materials with high plasticity can be mixed or the number of layers of the green body can be reduced.  Compression and tensile cracks caused by high plasticity index of the raw material, excessive drying shrinkage or uneven shrinkage. Appropriately add lean materials and strengthen the homogenization of raw materials. The green body temperature is too low and the exhaust humidity at the inlet end is too high, causing condensation, which causes the green body to absorb moisture and soften, causing fracturing. The green body temperature should be appropriately increased and the dehumidification air volume should be increased.  The drying vehicle surface is uneven. The vehicle surface should be kept flat.  Vibration caused by collision of the drying vehicle leads to cracks. Operation management should be strengthened.

Strengthen the weathering and humidification of raw materials. Various raw materials and internal fuels should be mixed evenly. Impurities in the raw materials should be removed in time to ensure uniform drying and shrinkage of the blanks. Timely repair the raw material preparation equipment to meet the process and technical requirements to ensure the quality of raw material crushing and mixing. Prevent uneven crushing, mixing, extrusion and other processes due to equipment problems, which may cause cracks in the blanks. Timely repair and replace the extruder auger to prevent cracks caused by excessive wear of the auger, unbalanced raw material extrusion speed, inconsistent blank density and inconsistent drying shrinkage. Keep the strip cutter flat, repair or replace the extruder mouth to prevent the mud strips from being bent when passing through the strip cutter due to unevenness, causing cracks in the blanks; prevent cracks caused by uneven water (oil) paths at the four corners of the extruder mouth. When water is discharged from the blank, a large capillary force will be generated, and its value can reach 70kg/m3. Only by providing a homogeneous and healthy green body can the occurrence of drying cracks be avoided.