In modern alumina production processes, solid-liquid separation has always been a critical step that significantly impacts production efficiency, energy consumption, and product purity. Particularly in the Bayer process for alumina production, the filtration of highly concentrated sodium aluminate solutions poses immense challenges, placing stringent demands on equipment, filter cloths, and operational techniques. The characteristics of high viscosity, high alkalinity, and a strong tendency toward crystallization often lead to issues such as clogging, inadequate dewatering, or uneven filter cake formation in conventional filtration systems and filter cloths during prolonged operation. These problems, in turn, can compromise the stability and cost-effectiveness of the entire production process. 

As a leading enterprise in the research, development, and manufacturing of filtration materials and systems,  CITIUS Leveraging its deep technological expertise and extensive industry experience In the research and application of dewatering filter cloths for vertical pressure filters, a unique technological system has been established, providing the alumina hydroxide industry with efficient, stable, and customized filtration solutions. 

I. Production Process of Aluminum Hydroxide and Characteristics of High-Concentration Sodium Aluminate Solution 

The Bayer process for preparing aluminum hydroxide primarily involves the following steps: alkali digestion of bauxite, solid-liquid separation, settling, washing, and drying. Among these, The filtration step for the highly concentrated sodium aluminate solution is one of the core processes. Its typical characteristics include: 

1. Strongly alkaline environment : The high concentration of sodium hydroxide in the solution places stringent demands on the chemical resistance of the filter cloth. 
2. High viscosity and high solids concentration : High-concentration systems have poor fluidity and are prone to clogging the filter cloth surface or the gaps in the filter plates. 
3. The particle distribution is fine yet uneven. : The tiny solid particles in the sodium aluminate system place precise demands on the filter cloth's pore size and structural design. 
4. Crystal Risk : High-concentration systems are prone to crystal deposition due to temperature fluctuations or improper operation, which can affect the filter cloth lifespan and filtration efficiency. 

These characteristics dictate that filter cloths must not only possess high strength and chemical-resistance material properties, but also require careful weaving, optimized thickness design, and advanced surface treatments to ensure both efficient filtrate flow and effective filter cake formation. 

II. Advantages and Applications of Vertical Filter Presses 

Vertical Pressure Filter Vertical Filter Press ) Due to its unique structural design, it demonstrates significant advantages when handling high-concentration, high-viscosity, and high-alkali systems: 

1. High pressure is evenly distributed. The vertical filter chamber design ensures uniform stress on the filter cake, allowing for rapid and stable discharge of the filtrate. 
2. High space utilization : The filter chambers are arranged vertically, minimizing the equipment footprint and making them ideal for high-capacity operations. 
3. Filter cake thickness is controllable : Facilitates control of the filter cake's moisture content, optimizing the subsequent drying process. 
4. Maintain convenience : The filter plate is easy to assemble and disassemble, reducing downtime and enhancing production continuity. 

However, the efficient operation of a vertical pressure filter depends on the performance of the filter cloth. In high-concentration sodium aluminate systems, if the filter cloth has uneven pore sizes or insufficient strength, it can easily lead to reduced filtrate permeability, uneven filter cakes, or even deformation of the filter cloth—directly impacting the stability and productivity of the entire process. 

III. Technical Requirements for Dehydrated Filter Cloths 

During the treatment of highly concentrated sodium aluminate solutions, the filter cloth must possess the following key properties: 

1. High dehydration efficiency : Able to quickly discharge the filtrate, reducing the moisture content of the filter cake. 
2. Precise interception : The pore size distribution is uniform, effectively trapping even tiny particles while ensuring the clarity of the filtrate. 
3. Alkali-resistant and chemically corrosion-resistant : At high concentration NaOH Under the given conditions, long-term use does not result in hydrolysis or structural degradation. 
4. High Strength and Stability : Withstands high-pressure filter chamber compression in vertical filter presses—remains deformation-free and prevents collapse. 
5. Easy to clean and renewable :The filter cloth surface treatment is optimized to minimize clogging, supports backwashing and chemical cleaning, and extends its service life. 

Based on these requirements, the filter cloth material selection, weaving process, thickness design, and surface treatment must all be optimized specifically for high-concentration sodium aluminate solutions, ensuring the long-term stable operation of the vertical pressure filter. 

IV. Xadias' Technical Solutions 

As Expert in filtration technology solutions for the alumina industry Xiadis offers systematic solutions in the area of dewatering filter cloths for vertical pressure filters: 

1. Core Technology and Patent Support : The company owns 9 A utility model patent, 11 A utility model patent and 1 This design patent covers the company's R&D achievements, encompassing end-to-end technical capabilities—from slice adhesion enhancement, drawing, and warping, all the way through weaving, shaping, cutting, and edge sealing. 
2. Material and Structural Optimization : For high-concentration, high-alkali systems, develop alkali- and abrasion-resistant materials, and enhance dewatering efficiency and filtrate flux through a multi-dimensional weaving structure. 
3. Customized Development Capabilities : Customized development of filter cloth—tailored in terms of size, thickness, pore size, and surface treatment—can be swiftly implemented to meet the diverse needs of different customers and operating conditions. 
4. Quality and Reliability Assurance : The product is delivered through ISO 9001 Quality management system certification ensures stable filter cloth performance and consistent batch-to-batch quality. 
5. Industry Standards and Technological Leadership Xiadis has participated in drafting several national and mechanical industry standards, such as "Belt Filter Machine Weaving Filter Belts." JB/T 10967-2017 )、"Testing Method for Filtration Performance of Woven Filter Fabrics Used in Solid-Liquid Separation" JB/T 11093-2011 ), possessing authoritative guidance capabilities in filter cloth selection and application. 

V. Application Practice and Effects 

In practical applications across multiple alumina enterprises, Xadias dehydration filter cloths have demonstrated outstanding performance in vertical pressure filters: 

1. The moisture content of the filter cake decreases. : Through an efficient dehydration design, the moisture content of the filter cake is reduced on average. 3% to 5% , reducing subsequent drying energy consumption. 
2. Improved filtrate clarity : Precisely intercepts fine particles, enhancing the reuse rate of mother liquor while minimizing rework and waste liquid discharge. 
3. Extended operational cycle : The filter cloth exhibits excellent resistance to high alkali, abrasion, and compression, significantly extending its service life. 20% That's all. 
4. Maintenance costs decrease : Surface treatment reduces clogging and mud buildup, extending the cleaning and replacement cycles while lowering operation and maintenance costs. 

These advantages not only enhance the company's production efficiency but also optimize the stability and cost-effectiveness of the entire alumina hydroxide production process. 

6. Industry Value and Future Trends 

As the alumina hydroxide industry expands and demand for high-purity products rises, technological upgrades in the filtration process have become a crucial strategy for companies to enhance their competitiveness. 

1. High-Concentration System Adaptability : In the future, filter cloths must maintain efficient dewatering capabilities even in systems with higher solids content and greater viscosity. 
2. The Integration of Intelligence and Automation : By integrating a vertical pressure filter with a sensor-based monitoring system, real-time monitoring of filter cake thickness and filtrate permeability is achieved, enabling process optimization. 
3. Environmental Protection and Energy Conservation Requirements : Reducing the moisture content of filter cakes lowers energy consumption while also minimizing wastewater discharge, enabling green production. 
4. Customization and modularity : Offering personalized filter cloths and system configurations tailored to different operating conditions, we meet the diverse needs of our customers. 

CITIUS, backed by its technological expertise and innovative capabilities, has already achieved mass-producible, replicable high-performance filtration solutions across multiple application scenarios, providing the industry with reliable technical support. 

VII. Conclusion 

In the filtration process of high-concentration sodium aluminate solution containing aluminum hydroxide, a vertical pressure filter combined with high-performance dewatering filter cloths is key to achieving efficient, stable, and low-energy consumption production. CITIUS, the expert in filtration technology solutions for the alumina industry , leveraging patented technologies, end-to-end production capabilities, and customized development services, we can help businesses optimize filter cloth selection, enhance solid-liquid separation efficiency, and reduce energy consumption and operational maintenance costs. 

As the industry upgrades and technology advances, the combination of high-performance filter cloths and advanced vertical pressure filters will play an increasingly central role in solid-liquid separation processes for alumina hydroxide production and other high-concentration, high-viscosity systems.