Application of Rotary Vacuum Filter in Alumina Industry

Application of Light Metal Equipment* Rotary Vacuum Filter in Alumina Industry Chen Changlin, Ma Hong (Jiangsu Xinhong Dapei Petrochemical Machinery Co., Ltd., Xinghua 225721, Jiangsu, China) Industry, This article describes the application of this filter in the aluminum industry, and it is also used in import filtration. The machine was compared u: rotary vacuum filter; separation; filter cake alumina production process, the decomposition process of aluminum hydroxide slurry separation and washing requires the use of separation and filtration devices. The traditional separation equipment includes Rotary Drum Vacuum Filter and belt filter. In recent years, it has gradually been replaced by imported rotary vacuum filter. The following describes the working principle and structural features of the turntable vacuum filter produced by our factory. The buckets are spliced into a horizontal ring-shaped filter plane, and the filter cloth is coated on the filter surface. According to the size of the filter, the support beams for the filter bucket are different. It is mounted on the drive pin wheel and drives the pin wheel through the gear reducer of the motor. The filtering surface of the filter is used for horizontal rotation.

Rotary vacuum filter working principle and structure as shown.

1 working principle and structure of the rotary vacuum filter The rotary filter of the rotary vacuum filter is composed of several fan-shaped filter rotary disc vacuum filter structure diagram (elevation) Each fan shaped filter bucket has a discharge pipe under the vacuum chamber. These discharge tubes are collected in a filtrate manifold, and the filtrate manifold of each fan-shaped filter cartridge is connected to a gas center distribution valve using an acid-resistant hose.

The circular filter surface is determined according to the process performance using a steel plate made of a cylindrical shape, so that the fixed internal and external cylinders, the filter surface and the barrier between the working areas form a volume cavity, so that the filter is added Slurry, washing liquid will not overflow and string position.

When the filter slurry added by the filter is vacuum-filtered and washed to form a filter cake, the screw discharge device on the filter surface will push the filter cake from the inner ring to the outer edge and fall into the flooding tank, leaving the filter cloth. There is a small amount of cake on the filter cloth that can be regenerated by back blowing.

The central distribution valve is divided into upper and lower layers. The upper distribution valve rotates synchronously with the filter plate. The lower distribution valve is fixedly installed on the center column. There is a wear-resistant seal between the upper and lower distribution valves. When they are rotated relative to each other, the seal is kept airtight under the effect of vacuum. According to the process requirements of filtration production, the lower distribution valve is provided with a continuous operation zone such as a filtrate zone, a washing zone, a secondary washing zone, a slag discharge zone, a filter cloth regeneration zone, etc. Each operation zone is corresponding to a vacuum system.

A slurry hopper corresponding to the operation area of the center distribution valve is provided on the filter surface of the rotary vacuum filter, and the filter slurry is uniformly distributed on the filter surface. Under the action of vacuum, the liquid and the solid are separated and the liquid is separated. Downstream through the filter cloth to the vacuum filter, the solids form a cake on the filter cloth. The washing liquid is evenly sprinkled on the cake surface with a lotion dispenser for washing. Between the different working areas, the filter surface is suspended above the filter surface, and the liquid does not mix the cantilever arms between each area, which affects the flatness of the filter plate, thereby ensuring the smoothness of the filter during operation.

(5) Drive pin wheel: This is a steel circular ring rotation part.

The drive pin wheel has drive pin teeth.

(6) Supporting roller: A plurality of supporting rollers are arranged in an annular supporting plane which supports a steel rail which drives the lower bottom surface of the pin wheel so that the driving pin wheel rotates horizontally on the supporting horizontal surface of the supporting roller.

(7) Screw unloading device: The spiral unloading device consists of an electric motor, a speed reducer, and a multi-head large pitch screw unloader. One end is mounted on the central operating platform of the center column and the other end is mounted on the floor support on the outer edge of the filter. The installation height can be adjusted to maintain a proper distance between the bottom of the spiral and the cloth surface.

(8) Filtrate Dispenser: It distributes the slurry evenly on the filter cloth Table Rotary disk Vacuum filter structure diagram (plane) 2 Rotary disc vacuum filter Structure Description (1) Drive device: The drive device is composed of a motor, a speed reducer, and a star wheel. In addition, it is equipped with a frequency converter for the motor to adjust the speed of the motor.

(2) Retainer: Installed inside the drive pin, the rotation center of the drive pin wheel is set in the axis of the circle formed by a plurality of stop wheels.

(3) The fan-shaped filter hopper: The main unit of filtration, spliced by a number of fan-shaped filter hoppers into a horizontal circular filter surface, the filter surface is covered with a filter cloth. Each fan-shaped filter hopper consists of a vacuum chamber, a discharge pipe, and a filtrate manifold.

(4) Floating support beam: The floating support beam is installed on the top surface of the driving pin wheel, which supports the filter bucket to keep horizontal stability and is driven by the driving pin wheel to rotate synchronously. The floating support structure of the support beam ensures that the expansion displacement of the filter bowl is not limited. Overcomes the entire filter surface and also prevents the solids in the slurry from depositing in the slurry hopper.

(9) Stopper: The stopper consists of a baffle holder and a rubber baffle, which separates the liquid between two different work areas so that they do not collude with each other.

3 Application of Vacuum Filter in Alumina Industry Jiangsu Xinhongda Company successively is Chongqing Nanchuan Alumina Factory (HDZP * 30, 1), Pingdingshan Huiyuan Chemical Industry Company (HDZP-30, 1), Chongqing Dingtai Tuoyuan Alumina Development Co., Ltd. has 2 sets) and Guizhou Qingzhen Alumina Plant (HDZP 55-1) has provided a rotary vacuum filter, which has a good use effect.

The following uses the HDZP-55m2 filter in Guizhou Qingzhen Alumina Factory as an example to describe its performance indicators: (1) Total filter area: 55m2 Effective filtration area: 46m2 (2) Vacuum: Absolute pressure ~ 34kPa (3) Filter rotation speed: 2 ~5min/r (4) Feeding device: 1 set (5) Lottery device: 2 sets (6) Filter Rotary Diameter: (Outer Disk Diameter) Y900 (7) Drive Motor Power: 7.5kW (8) Unloading Screw Motor Power: 11kW (9) Dial Accuracy Requirement: Rotor Diameter Deviation: *2mm inner diameter deviation of turntable: *2mm flatness of turntable: *1. 5mm gap between turntable and material spiral: +5 (easy to adjust) Performance of treated aluminum hydroxide slurry: ~80*C (top temperature of hot water 95 increased The vertical distance between the motor base and the suspended bearing is adjusted by using a method of reducing the thickness of the backing plate to meet the site requirements.

b. Replace bearing ring and L-shaped beam with countersunk head bolt to avoid unsafe factors caused by weld cracking.

c. For the uneven processing of the gutters, we made the model to correct the gutters and guide the workers to operate carefully to solve the pressing problem of the filter cloth.

6 Benefits The import price of this equipment is 1.5 million yuan more than the price of our factory.

When applied to the aluminum hydroxide product filtering and washing process, the process flow is greatly simplified, and all economic indicators far exceed the 40m2 rotary drum filter: 40% reduction in filter cloth loss, 30% reduction in energy consumption, and 30% reduction in energy consumption. Small area can reduce infrastructure investment.

Due to its high degree of automation, the labor intensity of the operator is reduced, and labor costs are reduced.

The equipment is simple in operation, reasonable in structure, reduces the leakage of materials, is conducive to environmental protection, and has huge social benefits.

7 Conclusion Through careful production and adoption of the above improvement measures, after the alumina plant's trial operation, it proved that the equipment runs smoothly, with high filtration efficiency and low product moisture content, which satisfies production requirements well. Compared with similar imported equipment, its product performance and manufacturing precision have basically reached the international advanced level, indicating that the development of the 51m2 flat pan filter is a success and can completely replace imported products. We will summarize the successful experience of this production, further improve the design and manufacturing process of the 51m2, 40m2, and 30m2 flat pan filter, and gradually promote it throughout the country to provide a more advanced filtration facility for domestic alumina refineries. Convenient and more economical choice.