Process characteristics and considerations of batching in aerated concrete production line
October 11, 2021
When the aerated concrete production line is working, the general environment is under normal temperature. The mixing equipment is used to promote the reaction between raw materials and water and release gas to expand the slurry. While hardening cement and lime, the finished products of aerated concrete equipment show porous structure. The second stage occurs under high temperature conditions, Cao and gas react in the aerated concrete equipment, which greatly increases the strength of the final product and ensures the high quality and high standard of the final aerated concrete.
Technological characteristics of batching in aerated concrete production line
There are three kinds of raw materials for batching: liquid materials, slurry materials and powder materials. In addition, there are aluminum powder or aluminum powder paste.
1. measurement of liquid materials
Liquid materials are usually measured by volume measuring tank. The structure is a cylinder with a certain volume (the lower part is conical), the inlet and outlet pipe is equipped with a solenoid valve, and the simplified body is connected with a liquid level indication controller.
2. measurement of slurry materials
Slurry materials are measured by slurry metering tank, which can be divided into volume metering type and weight metering type. The volume metering slurry metering tank is controlled by the observation surface of the glass level gauge. Its structure is relatively simple, the measurement accuracy is not high, and it is not convenient for automatic control; The weight slurry metering tank generally takes the sensor as the metering element, which has high metering accuracy and is convenient for automatic control, but the structure is complex.
3. measurement of powdery materials
Powder materials are measured by weight, and lever type powder weighing scales and electronic sensor type powder weighing scales are widely used. The structure of the lever scale is relatively simple, but the measurement accuracy is not high, the incoming and outgoing materials are not intuitive, which is easy to cause misoperation, and most of them can only measure one material, which complicates the layout of the batching system; The electronic sensing scale has high measurement accuracy, can realize automatic recording and full program control, and can measure multiple materials. The indication of metering incoming and outgoing materials is clear, so as to avoid misoperation, but it has high requirements for equipment maintenance.
4. measurement of aluminum powder
The amount of aluminum powder and aluminum powder paste is small, which are generally measured manually, but the sanitary conditions are poor. In foreign countries, aluminum powder is prepared into aluminum powder suspension, and then the aluminum powder suspension is measured according to the proportioning amount, which is generally suitable for large-scale enterprises; Domestic small and medium-sized enterprises also use to concentrate aluminum powder paste in one silo, send it to the metering scale through the feeder, and then send it to the aluminum powder mixer for mixing. However, due to the small amount of aluminum powder, it has a great impact on gas generation, and a slight error in measurement, it is easy to cause quality accidents. Therefore, most domestic factories still use manual measurement to ensure the accuracy of measurement.
5. mixing of materials
The mixing of materials and the pouring of slurry are completed by the mixer. The mixer must make all kinds of materials mix evenly in a short time and can be heated to adjust the temperature. Quickly disperse the aluminum powder suspension into the slurry in a shorter time (within 1min), and finally pour.
So what aspects should be considered in the batching of aerated concrete?
1、 To give full play to the dual role of chemical properties of raw materials and admixtures, and make use of their best combination efficiency to reduce water binder ratio and cement and water consumption, admixtures and admixtures suitable for customers to put into operation aerated concrete equipment should be selected to ensure the matching of the two.
2、 Considering the optimum content of raw materials, it must be obtained through trial mixing and comparison. It is necessary to strictly prevent the insufficient proportion and avoid the side effects of excessive auxiliary raw materials of admixtures, and minimize the water binder ratio to improve the pore structure of aerated concrete equipment products, so as to increase the compactness, which is the key factor to improve the durability and strength of finished products. In particular, it is worth reminding that high-efficiency composite admixtures should be selected, and the best dosage should be tested; For aerated concrete products with different functions, the proportion of raw materials shall be designed and planned according to their uses.
3、 Raw material admixtures with low water demand and high substitution rate shall be selected. Reduce cement and water consumption as much as possible, because high cement consumption or excessive volume of cementitious material slurry will bring certain losses.