Pilot-Scale Application Record of a Novel Nanomicro-Powder Filtration System in the Alkaline Oxide Water-Washing Separation Process — An Engineering Pathway for Efficient Dealkalization and Stable Recovery of Nanoscale Powders

Release time:

2026-05-06

Achieving efficient solid–liquid separation and thorough washing of alkaline oxide powders with a particle-size distribution of D10 = 100–150 nm and D50 ≈ 400 nm in high-alkali systems at pH 11–14 has long been a challenging issue in the industry. This paper presents an analysis based on pilot-scale operational data from a novel nanomicro-powder filtration machine, focusing on the separation mechanism, process control, and washing efficiency. The experimental results demonstrate that, in a suspension with a solids content of approximately 20%, optimizing the filtration and washing procedures enables stable control of the filter cake pH below 9 while achieving a recovery rate of ≥90%. This approach significantly reduces water consumption and enhances product purity, thereby validating the engineering applicability of this equipment for the processing of nanoscale powders.

In the fields of fine chemicals and high-end powder materials, the post-processing of alkaline oxides has long been a process step that “appears simple but is in fact complex.” This is especially true when particle sizes enter the nanoscale range, as conventional water washing and solid–liquid separation methods often struggle to achieve both efficiency and thoroughness. Alkali Removal Efficiency, Recovery Rate, and Operational Stability 。

Recently, a pilot-scale trial conducted on a certain alkaline oxide powder confirmed the feasibility of applying a novel nano–micron powder filtration machine to this type of system. Based on the complete experimental procedure, this paper provides a systematic analysis of the technical approach and the resulting outcomes.

I. Project Background: Challenges in the Treatment of Nano-Scale Alkaline Powders

The material being processed this time is an alkaline oxide powder, with the following key parameters:

  • Particle size distribution:
    • D10: 100–150 nm
    • D50: approximately 400 nm
  • Initial system characteristics:
    • Suspension pH: ≈14
    • Solvent: Pure water
    • Solid–liquid concentration: approximately 20% (experimental formulation)

This system exhibits typical characteristics:

1. Strongly alkaline environment (pH 11–14)

This places stringent requirements on the filtration material and system stability, while also increasing the difficulty of cleaning.

2. Strong dispersion of nanoscale particles

Particles remain suspended for extended periods, rendering conventional sedimentation methods largely ineffective.

3. High washing demand

The powder needs to be washed from strongly alkaline to Weakly alkaline (pH < 9) , and it must be uniform and stable.

II. Customer Objectives and Process Requirements

The core objectives of this pilot-scale trial include:

1. Process Objectives

  • Achieve Solid-liquid separation + multi-stage water washing
  • Wash the powder with deionized water until it reaches a slightly alkaline pH.

2. Quality Assessment Criteria

The following detection method is adopted:

  • Take a small amount of the washed powder.
  • Dry at 100–110°C.
  • According to 1 g of powder : 20 g of water Stir.
  • Test the pH of the solution

👉 Determination requirements: pH < 9

3. Process Constraints

  • Unit washing water consumption:
    👉约 60–70 kg of water per 1 kg of powder
  • Target Production Capacity:
    👉 Approximately 1 ton per day
  • Recovery rate requirement:
    👉 ≥90% (acceptable)

III. Issues Facing Traditional Crafts

Common issues in such nano-alkaline systems include:

1. Cannot be washed clean

  • Alkaline ions are difficult to completely replace.
  • Severe residual in the filter cake

2. Cannot be filtered out

  • Nanoparticle penetration of the filter medium
  • or rapid blockage leading to shutdown

3. Low recovery rate

  • Severe fine-particle loss
  • Causing material loss

4. High water consumption but low efficiency

  • Although a large amount of water is used (60–70 times the volume), the washing is uneven.

IV. Technical Approach for the New Nano- and Micro-Powder Filtration Machine

To address the aforementioned issues, this device employs a separation mechanism that differs from conventional filtration:

1. Dynamic Filtering Structure

A stable filter layer is formed during the filtration process, achieving:

  • Efficient nanoparticle retention
  • Prevent particle penetration

2. Controllable Filter Cake Structure

The filter cake possesses:

  • Good pore connectivity
  • Facilitates uniform penetration of the washing solution.

thereby enhancing Washing Efficiency and Alkali Removal Effect

3. Multi-stage Washing Synergy

Stacked on top of filtering:

  • Continuous or batch washing
  • Enhance ion exchange efficiency

4. Anti-clogging Design

Through fluid distribution optimization:

  • Reduce local deposition
  • Maintain a stable flux

V. Pilot-Scale Experimental Procedure

This experiment was conducted according to the following procedure:

1. Slurry Preparation

  • Prepare a suspension using dry powder
  • Solid-liquid concentration: approximately 20%
  • Initial pH: approximately 14

2. Filtration Stage

  • Establish a stable filter layer
  • Achieve preliminary solid-liquid separation

3. Washing Stage

  • Perform multi-stage washing using pure water.
  • Control the wash water volume (refer to 60–70 kg per kg of powder).
  • Gradually reduce the alkalinity of the filter cake.

4. Drying and Testing

  • Drying temperature: 100–110°C
  • Reconstitute and measure pH according to the standard ratio.

VI. Experimental Results and Analysis

1. Alkali Removal Effect

👉 Final test result: pH < 9

Explanation:

  • Alkaline components are effectively removed.
  • Thorough washing process

2. Filtrate Performance

  • The filtrate is clear.
  • No obvious particle entrainment

Indicates:

👉 Nanoparticles achieve stable retention

3. Recovery Rate

👉 Reach or approach More than 90%

Explanation:

  • Controllable powder loss
  • The process is economically viable.

4. Operational Stability

During the experiment, the following was observed:

  • No obvious blockage
  • Flux stability
  • Operation window width

VII. Summary of Key Technological Advantages

Based on this pilot-scale trial, the core advantages of this equipment in alkaline nanomaterials can be summarized as follows:

✔ High-precision retention

Suitable for 100 nm-class particle systems

✔ Efficient washing performance

The filter cake structure facilitates ion exchange and water-washing penetration.

✔ Stable operation

Avoid clogging and fluctuations associated with conventional filtration.

✔ Scalable for industrial production

Adapted for a capacity of one ton per day

VIII. Industrial Application Value

This technological approach holds broad application prospects in the following fields:

  • Nanometer-scale oxides (TiO₂, Al₂O₃, etc.)
  • Battery material precursor
  • Fine Chemical Powders
  • New Energy and Functional Materials

Especially in “ High-alkali system + nanoparticles + high-purity requirements “In the scenario, the advantage is even more pronounced.”

IX. Conclusion

The results of this pilot-scale trial demonstrate that, even in a complex system with particle sizes on the order of 100 nm and strongly alkaline conditions (pH ≈ 14), the novel nano–micron powder filtration machine is still capable of achieving:

  • Stable solid-liquid separation
  • Efficient water washing and alkali removal
  • Controllable recovery rate

and ultimately meet the process specifications specified by the customer.

This not only validates the equipment’s performance, but more importantly demonstrates—
The “integrated filtration and washing” process for nanoscale powders is now ready for full-scale engineering implementation.

In the future competition for high-end materials, such seemingly fundamental separation processes are emerging as critical determinants of product quality and cost.

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How can the filtration challenge of highly alkaline cuprous oxide powder be overcome?

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Practical Application of a Novel Nano- and Micropowder Filtration Machine in the Nanoscale Separation of Titanium Dioxide

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