Chemical Liquid Filter Part 1: Material & Temperature Selection Guide

Author: James Sang

Introduction

Chemical liquid filters are essential components in many industrial processes. Common liquid systems include cartridge filters, bag filters, magnetic filters, vertical filters, and chemical-resistant liquid units used together with magnetic drive pumps, centrifugal pumps, self-priming pumps, and diaphragm pumps.

The main purpose of a chemical filter is to remove solid particles, metal powders, chemical crystals, suspended impurities, and other contaminants from process liquids. A properly selected filter protects pump bearings, mechanical seals, impellers, and magnetic drive isolation components while improving liquid quality and maintaining stable production performance.

However, incorrect filter selection may cause frequent clogging, chemical corrosion, housing damage, poor liquid efficiency, excessive pressure loss, and even pump cavitation.

A professional chemical filter selection process should consider five key factors:

· Chemical compatibility

· Operating temperature

· Liquid accuracy

· Flow rate

· Filter structure

This guide explains how to select the correct chemical filter material and structure for different industrial applications.



1. Analyze Liquid Conditions Before Selection

Before choosing a filter, always evaluate the actual operating environment, including chemical properties, temperature, particle type, and purity requirements.

1.1 Select Filter Housing Material Based on Chemical Compatibility

PP / FRPP Filter Housing (Polypropylene)

Recommended Applications:

· Dilute hydrochloric acid

· Dilute sulfuric acid

· Alkaline cleaning solutions

· Electroplating rinse water

· Neutral wastewater

Typical Temperature: ≤65°C

Advantages:

· Good chemical resistance

· Lightweight design

· Cost-effective

· Widely used in general chemical processes

Not Recommended For:

· High-temperature concentrated acids

· Hydrofluoric acid (HF)

· Strong organic solvents such as ketones and esters



PVDF Chemical Filter Housing

PVDF (Polyvinylidene Fluoride) is widely used for advanced chemical liquid applications.

Recommended Applications:

· Strong acids and alkalis

· Hydrofluoric acid systems

· High-temperature electroplating solutions

· Lithium battery electrolyte

· PCB etching chemicals

Temperature Range: Up to approximately 90°C

Advantages:

· Excellent corrosion resistance

· Better HF resistance than PP

· Improved solvent resistance

· Suitable for high-purity applications

Common Industries:

· PCB manufacturing

· Semiconductor

· Lithium battery

· Surface treatment



304 / 316L Stainless Steel Filter

Recommended Applications:

· Pure water

· Cooling water

· Food processing liquids

· Non-corrosive solvents

Advantages:

· High mechanical strength

· Excellent pressure resistance

· Easy cleaning and maintenance

Not Recommended For:

· Hydrochloric acid

· Chloride-containing chemicals

· Hydrofluoric acid (HF)

These chemicals may cause rapid corrosion and penetration damage.



PTFE / PFA Lined Stainless Steel Filter

Designed for highly demanding chemical environments.

Recommended Applications:

· High-temperature corrosive chemicals

· High-purity electronic chemicals

· Strong oxidizing chemicals

· Semiconductor processes

· Fine chemical production

Advantages:

· Excellent corrosion resistance

· High temperature capability

· Reduced risk of metal contamination



1.2 Filter Material Selection by Temperature

Operating Temperature

Recommended Material

≤65°C

PP / FRPP Filter

65–90°C

PVDF Filter

>90°C

PTFE / PFA Lined Filter

Higher operating temperatures require stronger chemical resistance and better mechanical stability.



1.3 Select Filter Structure According to Contaminants

Different particles require different liquid designs.

Fine Particles

Examples:

· Nickel particles

· Copper particles

· Fine suspended solids

· High-purity chemical contamination

Recommended: Cartridge filter system

Advantages:

· High liquid accuracy

· Stable liquid performance

· Suitable for precision processes

Applications:

PCB plating, semiconductor cleaning, lithium battery electrolyte circulation.



Large Amount of Solid Waste

Examples:

· Metal residue

· Chemical crystals

· Etching particles

· Sludge

Recommended: Bag filter system

Advantages:

· Large dirt-holding capacity

· Longer service interval

· Easy filter replacement



Fibers and Soft Contaminants

Examples:

· Textile wastewater

· Paper industry wastewater

· Organic fibers

Recommended: Two-stage liquid

· Coarse basket filter

· Fine liquid system



Large Hard Particles

Examples:

· Sand

· Metal chips

· Large debris

Recommended: Y-type strainer

Main Function: Protect pumps from damage.



1.4 Special Requirements: Explosion Safety and High Purity

Lithium Battery Electrolyte Liquid

Requirements:

· Corrosion resistance

· Low contamination

· Explosion safety

Recommended Configuration:

· PVDF filter housing

· Anti-static design

· Grounding connection

· PTFE filter element



Semiconductor Chemical Liquid

Requirements:

· Ultra-clean liquid

· Low metal ion contamination

· High chemical purity

Recommended Configuration:

· PFA-lined filter housing

· PTFE filter element

· High-purity liquid design



Conclusion

Chemical filter selection is not only about liquid accuracy. Material compatibility, temperature resistance, contaminant characteristics, and industry requirements must all be considered. Choosing the correct filter design helps improve equipment reliability, reduce maintenance costs, and ensure stable production quality.