The batching system includes small material bins, feeding scales, and feeding screws. Its function is to provide raw material aluminum hydroxide to the batching machine. During the production process, the amount of aluminum hydroxide discharged can be adjusted to meet the control indicators of the batching furnace temperature, thereby achieving the control of product quality. The system consists of a screw feeding machine, a preheating cyclone, a batching main furnace, a cooling cyclone, a fluidized cooling bed, and a conveying system. The raw material aluminum hydroxide is stored in the small material bins by the conveying equipment during production, and then weighed by the adjustable-speed feeding scale before being sent by the feeding screw to the dryer for drying. The dried aluminum hydroxide is sent to the preheating cyclone for pre-batching, and the pre-batched material is sent to the batching main furnace to complete the final batching and quality adjustment. The generated products pass through the thermal separation cyclone, cooling cyclone, and cold air for heat exchange to cool down, and then the aluminum oxide exiting the cooling cyclone enters the fluidized bed cooler for final cooling. The aluminum oxide with a temperature lower than 80℃ is sent into the aluminum oxide storage bin through the pneumatic chute and aluminum oxide conveyor belt for storage.

The aluminum oxide weighing system adopts two-step vibration, that is, in the initial stage of screw feeding, the rapid screw feeding is at 90% of the set value, and the remaining 10% is fed at a slow speed. This reduces the large overshoot and feeding error caused by the rapid screw. The entire screw batching process is controlled by a computer, and the current screw feeding is compensated based on the difference between the actual value and the set value of the previous screw feeding. Analyzing the screw feeding and weighing control process reveals that after the feeding stops, due to the height difference between the screw feeding machine and the weighing bin, the uncertainty of the spatial materials, as well as the large and small pieces of the materials, and the inertia of the screw feeding device, are the direct causes affecting the final weighing accuracy. If the errors caused by the above reasons can be accurately estimated, the final weighing result can be kept within the given range, improving the batching accuracy. This method mainly solves the problem of large cumulative errors in the continuous batching process, making the actual batching of the batching machine consistent with the set value, and controlling the actual material input to the furnace to approach the set value regardless of the length of the production time, and the actual material input to the furnace tends to the set value over time.

The electronic scale uses three weighing modules installed at the three corners of an equilateral triangle plane to evenly distribute the force on the three weighing modules. The three weighing modules of each electronic scale are connected in parallel, and each weighing module also adds a compensation circuit to the mixing system to compensate for the slight technical parameter differences of each weighing module and to adjust the inconsistent output of the weighing modules caused by the uneven force on the weighing modules during installation of the electronic scale, improving the repeatability, stability, and accuracy of the system. While using high-precision weighing modules, an intelligent compensation control algorithm is adopted to meet the batching accuracy of the process conditions, ensuring that the batching accuracy remains at the optimal state and improving the output and quality of the products.

The batching machine uses an electric screw feeding machine for screw feeding. The speed of the motor, that is, the rotational speed of the screw, is continuously adjustable. In the initial stage of screw feeding, the motor runs at high speed, and when the feeding value approaches the set value, the motor runs at low speed. The screw feeding speed is given by PLC. The environmental conditions of the aluminum material production industry drive the use of AC motors, to ensure the accuracy of speed adjustment. The speed control device uses a high-precision frequency converter to ensure the stability of screw feeding and overcomes the disadvantages of large inertia, large overshoot, and large errors of the electromagnetic vibration feeding machine. The screw feeding machines are independent and are driven by Mitsubishi frequency converters, with advanced functions such as torque, vector, slip compensation load adaptation, and also has complete protection functions such as overload short circuit, overvoltage, and undervoltage. To improve the braking speed of the screw feeding machine, the short-term overload capacity of the frequency converter is adjusted to 150%. To obtain an accurate amount of spiral feeding, it is necessary to set the deceleration stop time of the frequency converter reasonably. Based on this deceleration time, the frequency converter can calculate the overshoot amount of the material when operating at the maximum load.

The mixing system is composed of mixing spirals. The drive motors are all 3kW AC motors. To ensure that the raw materials and fuel are "matched at the beginning and end" during the batching process, the motor speed must be adjusted. The speed control device uses a frequency converter, and the speed is given by the PLC through calculation. For ease of operation and remote control, the frequency converter is set to be controlled by external terminals. The action process and speed setting are given by the computer. The alarm status is output by the frequency converter to the PLC. The PLC makes a system or equipment stop command through logical operations.

When the system starts working, the materials flow from the silo into two spiral feeders respectively. When the computer sends a conveying signal to the two spiral feeders, the materials quickly enter the hopper scale, and their weight is converted into an electrical signal by three weighing modules and sent to the weighing instrument. The latter converts it into a 4-20mA current signal and sends it to the PLC for processing. When the material weight reaches the set value (90%), the PLC sends a slow vibration signal to the spiral feeders, causing the materials to slowly enter the hopper scale until the scale reaches the set value. And the previous weighing error can be automatically compensated in the next weighing. When the discharging time is over, the computer sends a signal to start the mixing spiral, and then sends a signal to the solenoid valve. At this time, the cylinder installed on the hopper scale will push the fan-shaped gate plate open. The two materials pass through the intermediate hopper and are simultaneously sent out by the spiral, making the batching process "matched at the beginning and end". The mixed materials are sent to the next process, and then the second weighing and mixing start.