The production process of the alumina industry is complex, involving multiple key filtration steps. Filter cloth, as the core material for solid-liquid separation, directly affects product quality, washing effect, and production efficiency.In the red mud washing, slurry filtration, and seed washing stages of alumina production，the correct selection of filter cloth is particularly important. Xiamen Citius Filtration Materials Technology Co., Ltd., with 30 years of industry experience and continuously innovative technological advantages, provides efficient and stable filter cloth solutions for the alumina industry, helping enterprises improve production efficiency and reduce operating costs.

I. Red Mud Washing

1. Process Background and Filtration Difficulties
Red mud is a solid waste residue formed after alumina is extracted from bauxite using the Bayer process in alumina production. It has high viscosity, and the red mud filter cake after sedimentation is difficult to perform solid-liquid separation and is difficult to separate from the filter cloth, posing challenges to subsequent washing and separation processes.

2. Current Status of Filtration Equipment and Technology

Rotary drum filter:Currently, most alumina companies use rotary drum filters for red mud washing. Some companies improve the filter cake peeling effect and washing efficiency by adding a post-roll auxiliary unloading device.

Plate and frame filter press:Plate and frame filter presses use alternately arranged filter plates and frames to filter the slurry containing red mud under pressure, separating the solids from the liquid. The slurry forms a filter cake on the filter cloth, and the liquid is discharged through the filter cloth. Advantages: High filtration accuracy: effectively intercepts fine particles to obtain a drier filter cake. Application difficulties: High-viscosity red mud easily clogs the filter cloth pores and requires frequent cleaning; the processing efficiency is relatively low and is not suitable for large-scale production lines.

Horizontal vacuum belt filter: Some manufacturers also use horizontal vacuum belt filters for red mud washing, but due to the high viscosity of red mud, the filtration effect is not ideal, easily causing filter cloth clogging or filter cake residue.

Plate and frame filter press

3. Filter Cloth Selection and Advantages

Red mud washing filter cloths usually useHigh-performance filter cloth。 This filter cloth has the following advantages:

Uniform and stable mesh: The filter cloth structure ensures the water permeability and filtration accuracy of the filter cloth, preventing particle clogging of the filter cloth and improving the solid-liquid separation effect.

Good filter cake release: The filter cloth with surface calendering is easier to peel off the red mud filter cake, reducing the cleaning and maintenance cost of the filter cloth.

Strong corrosion resistance: Special materials are alkali-resistant and corrosion-resistant, and can maintain good performance stability in the strong alkaline environment of alumina red mud treatment.

4. Process Optimization and Application Effectiveness

Citius, through joint research with many alumina companies, has modified the filter cloth to improve its use effect on rotary drum filters and, by optimizing the filter cloth structure, achieved higher filtration efficiency and longer service life during red mud washing.

II. Slurry Filtration (Red Mud Overflow)

1. Process Background and Filtration Difficulties
Slurry filtration is the process of separating solids from liquids in the sodium hydroxide solution containing alumina formed after dissolving bauxite. The purpose is to remove impurities and ensure the stability of subsequent processes. Because the filtration equipment needs to operate under high temperature, high pressure, and concentrated alkaline conditions, it puts extremely high demands on the temperature resistance, alkali resistance, and pressure resistance of the filter cloth.

2. Current Status of Filtration Equipment and Technology

Horizontal leaf filter: Suitable for large-scale and efficient filtration conditions, the equipment operates stably, but the filter cloth requirements are high.

Vertical leaf filter: Large filtration area, suitable for continuous production, and the filter cloth also needs to have good alkali resistance and high-strength performance.

3. Filter Cloth Selection and Advantages

Slurry filtration filter cloths usually useHigh-density, high-performance filter cloth。 This type of filter cloth has the following characteristics:

Strong retention capacity: The dense twill structure of the filter cloth provides better fine particle retention capacity, effectively preventing impurities from entering downstream processes.

Excellent shaping and heat resistance: The filter cloth, after special heat-setting treatment, can maintain a stable shape and pore size under high temperature and high pressure, improving the filtration effect.

Outstanding alkali resistance: The alkali resistance of special materials allows the filter cloth to be used for a long time in concentrated alkaline solutions without deformation or failure.

4. Process Optimization and Application Effectiveness

The high-density, high-retention accuracy filter cloth developed by Citius, after special surface treatment and fine structural design, not only improves the filtration rate of slurry filtration but also increases the output by more than 30%, ensuring the purity and stability of the alumina solution.

III. Seed Washing

1. Process Background and Filtration Difficulties
Seed washing is a process in which the decomposed aluminate solution is concentrated to separate aluminum hydroxide, and repeated washing and filtration are carried out. The main purpose is to remove impurities from the surface of the crystals to ensure the purity of the aluminum hydroxide product. In this process, high-efficiency filter cloth is needed to ensure that the washed seeds reach the required purity and to avoid frequent filter cloth replacement leading to downtime.

2. Current Status of Filtration Equipment and Technology

Vertical filter:Because vertical filter presses have a large filtration area and a high degree of automation, they are widely used in seed washing processes.

Vacuum Belt Filter Press:Some companies also use vacuum belt filter presses for seed washing, but due to the high frequency of filter cloth replacement, the application effect is relatively low.

Vertical Plate Filter Press

3. Filter Cloth Selection and Advantages

Seed washing filter cloth, this type of filter cloth has the following advantages:

Abrasion resistance, long life:Filter cloths that have undergone special wear-resistant treatment can effectively extend their service life, reduce the frequency of filter cloth replacement, and thus reduce downtime.

Excellent filter cake release:The surface of the filter cloth has been specially treated, making the separation of seed filter cake smoother and reducing cleaning and maintenance costs.

Chemical corrosion resistance:Filter cloth made of special materials can operate for a long time in a strong alkaline environment, maintaining good physical properties.

Horizontal Vacuum Filter Press

4. Process Optimization and Application Effectiveness
By optimizing the filter cloth structure and surface treatment process, Xiamen Citius has improved the durability and filtration accuracy of the filter cloth, effectively reducing downtime caused by filter cloth replacement and improving production efficiency. At the same time, it provides customized filter cloth solutions for different process stages to ensure the stable operation of the seed washing process.

IV. Citius' Technological Advantages and Industry Contributions

1. 30 Years of Industry Experience and Professional R&D Capabilities
Xiamen Citius Filtration Materials Technology Co., Ltd. has been deeply involved in the filtration materials industry for 30 years, accumulating rich industry experience and technical strength. The company's independently developed filter cloth technology covers the entire process from yarn selection and weaving technology to surface treatment, ensuring high quality and stability of the products.

2. Customized Solutions
For the actual operating conditions of different alumina companies, Citius provides personalized filter cloth selection and process optimization services. Based on the characteristics of on-site equipment and filtration requirements, customized filter cloth products are tailored to help companies improve production efficiency and reduce operating costs.

3. Excellent Quality Control System
Citius strictly implements the ISO9001 quality management system in the production process, conducting strict inspection and control from raw material procurement to finished product delivery to ensure that each batch of filter cloth meets industry standards and customer usage needs.

V. Conclusion

In various key stages of alumina production, the selection and application of filter cloth is crucial. Xiamen Citius Filtration Materials Technology Co., Ltd., with its superior technical strength and rich industry experience, provides efficient and stable filter cloth solutions for the alumina industry. Through continuous technological innovation and optimization, Citius has not only improved the filtration efficiency of filter cloth, but also effectively extended its service life, helping alumina companies achieve higher production goals and making continuous contributions to the industry's development.