PE Sintered Membranes for Ultrafine Powder Washing

Against the backdrop of rapid upgrading in new energy and new materials industries, purity requirements for ultrafine powder materials continue to rise. Powder washing, the core process determining product quality and production cost, now faces challenges such as high water consumption and severe powder loss. Jiuwu Hi-Tech's independently developed PE sintered tubular membrane technology, built around cross-flow filtration, establishes a continuous washing process system of "powder washing - zero loss - automation", providing efficient, water-saving systematic solutions for titanium dioxide, lithium battery materials and other fields.

Industry Pain Points of Conventional Powder Washing Processes

Industrial powder washing currently relies mostly on conventional processes such as membrane filter presses and vacuum leaf filters, which expose multiple shortcomings in actual production:

1. Severe powder loss

Conventional equipment has insufficient retention capacity for nano-scale and sub-micron ultrafine particles. In the titanium dioxide industry, for example, the loss rate of membrane filter presses for ultrafine metatitanic acid particles reaches as high as 1000 ppm, wasting raw materials and increasing the solid waste load of downstream wastewater.

2. Persistently high washing water consumption

Achieving impurity removal targets requires large amounts of washing water; high water consumption pushes up water costs and simultaneously generates large volumes of production wastewater, increasing corporate pressure for environmental treatment.

3. Low washing efficiency, poor continuity

Most operations are intermittent; unloading and cloth changing rely on substantial manual labour, resulting in high labour intensity and long production cycles. Filter cloths are prone to blocking and damage, making stable continuous production difficult.

4. Large fluctuations in product purity

Removal efficiency for soluble impurity ions is limited, making it difficult to meet the stringent purity requirements of high-end new materials.

5. Large equipment footprint

Conventional equipment is bulky; retrofitting existing production lines with limited space is difficult and costly.

Core Process Flow of the PE Sintered Membrane Powder Washing System

Using ultra-high molecular weight PE sintered tubes as the support skeleton, with the inner wall coated with a high-precision PVDF separation layer, and adopting the internal-pressure cross-flow filtration principle, the system is built around three core process units:

Unit 1: Powder Recovery System

For waste acid, waste liquid and material leakage generated by upstream processes, the membrane separation unit efficiently intercepts and recovers entrained ultrafine powder. The recovered concentrated slurry returns to the process, while the filtrate proceeds to downstream treatment, reducing powder loss at the source.

Unit 2: Membrane Washing System

The slurry to be washed enters the first-stage washing tank, mixes with washing water and is fed into the membrane module. Driven by pressure, the slurry flows at high speed inside the membrane tube to form a cross-flow state; soluble impurity ions and free acid pass through the membrane layer with water molecules as permeate, while powder particles are fully retained and circulated. By continuously supplementing fresh demineralized water and extracting washing wastewater, the concentration of impurity ions is gradually reduced.

Unit 3: Membrane Separation and Concentration Unit

After multi-stage washing, qualified slurry enters the concentration stage to further increase solid content. Permeate can be reused in stages to upstream washing processes, achieving cascade utilization of washing water and minimizing fresh water consumption.

Cross-flow filtration principle: The slurry flows at high speed along the inner surface of the membrane tube, and the pressure difference perpendicular to the flow direction drives water molecules and impurities through the membrane pores. This prevents a thick filter cake layer from forming on the membrane surface, maintaining stable high flux over the long term, with washing efficiency far higher than conventional dead-end filtration.

Core Advantages of Jiuwu Hi-Tech PE Sintered Membrane Technology

99.9% - Retention rate for nano-scale ultrafine powder; filtration precision down to 0.05 μm

20%+ - Water saving; wash water ratio controlled at 10-30 times, lower consumption than plate-and-frame

80% - Improvement in continuous automated operation

pH 0-14 - Resists strong acids and alkalis; suits various corrosive conditions

Ultra-high retention precision, zero loss of valuable powder

Membrane filtration precision reaches the 0.05 μm level, with a retention rate of 99.9% for nano-scale ultrafine powder, completely solving the material leakage problem of conventional processes.

Significantly higher washing efficiency, over 20% water saving

Cross-flow filtration strengthens impurity removal; the wash water ratio is controlled at 10-30 times, reducing water consumption by 20% compared with plate-and-frame.

Excellent acid and alkali resistance, wide applicability

The combination of PE support body and PVDF separation layer enables long-term stable operation in a wide pH 0-14 acid-alkali environment, suitable for highly corrosive conditions such as titanium dioxide acid washing and lithium battery material washing.

80% improvement in continuous automated operation

Modular design plus fully automatic control enables stable 24-hour continuous operation without frequent manual unloading or cloth changing; with online backwash and chemical cleaning, the degree of continuous automation increases by more than 80%.

Higher product purity, supporting premium positioning

Membrane separation reduces soluble impurities to extremely low levels, significantly improving product purity and hue stability, helping enterprises enter high-end markets.

Small footprint, suitable for existing plant retrofits

Compact tubular bundle layout reduces system footprint by more than 50% compared with conventional processes; modular installation is particularly suitable for energy-saving retrofits of existing plants.

Verified Typical Application Cases

A titanium dioxide enterprise in Sichuan: ultrafine TiO2 washing project

After introducing the Jiuwu system, TDS of the washed slurry dropped from 120,000 ppm to 30 ppm; the wash water ratio was reduced by 50%, saving more than 10,000 tons of water per year; continuous automated operation substantially lowered labour costs and significantly increased the output rate of high-end grades.

A titanium dioxide enterprise in Inner Mongolia: plate-and-frame leakage recovery project

Equipped with the PE sintered membrane powder recovery system, the project achieves efficient interception and recovery of titanium dioxide from waste acid, with annual recovered material output value approaching ten million yuan; the clarity of the treated waste acid is greatly improved, facilitating subsequent resource recovery.

500 t/a ultrafine TiO2 production line project

The line fully adopts the tubular membrane washing process; after one month of continuous operation, membrane flux showed no obvious decline; particle retention rate above 99.9% with no loss of nano-scale TiO2; washing efficiency doubled, and system footprint is only 45% of the conventional process.

A pigment enterprise in Shandong: washing and purification project

An integrated solution of "pre-treatment + membrane washing + membrane concentration" greatly reduced product salt content and lifted quality to the high-end tier; washing water consumption fell by more than 50%, and wastewater discharge across the whole process dropped by 60%, significantly easing environmental compliance pressure.

Process upgrading is becoming the industry standard

As industrial powders continue to move toward ultrafine and ultra-pure grades, Jiuwu Hi-Tech's PE sintered membrane powder washing technology, with its combined advantages of high-precision separation, significant water savings, low material loss and continuous operation, is becoming the standard technology for process upgrading in titanium dioxide, lithium battery materials and other fields. In the future, Jiuwu Hi-Tech will continue to deepen membrane material R&D and process innovation, helping industrial production transition toward low consumption, high quality and sustainability.