Phlogopite MicaFort

Product information for phlogopite mica

PD900 – coarse phlogopite

• Typical D50: approx. 650 µm
• Production method: Dry-ground

PD900 is designed for structural and cement-based systems requiring thermal protection and crack resistance.

Primary applications:

• Sprayable fireproof cement
• Fire protection for structural steel
• Wallboards, joint compounds, and oil & gas construction materials
• Excellent feed stock for mica paper production

Performance in sprayable cement

In spray-applied fire protection systems, phlogopite:

• Provides thermal shielding through its plate structure
• Contributes to passive fire resistance
• Reduces drying stresses and cracking
• Enhances durability of the cement matrix

Typical mica loading in fireproof sprayable cement systems ranges between 10–20%, depending on formulation.

PW grades – wet-ground phlogopite

Wet-ground grades deliver higher aspect ratio and improved platelet integrity compared with dry-ground products.

Available grades:

• PW150 : fine
• PW80 : extra fine
• PW30 : ultra fine

Surface-treated grades:

• PW80S
• PW30S

Silane-treated grades enhance bonding between the mineral surface and polymer matrices, improving mechanical strength and dispersion in organic systems.

MicaFort packaging

Our MicaFort product range can be sold as 20kg paper sacks or 1200kg bulk bags. Some grades are also available in bulk. We suggest that you contact your sales representative to see if this applies to the grade you want to purchase.

Features and benefits

Why choose phlogopite MicaFort

Phlogopite mica provides performance advantages in demanding environments, particularly where elevated temperature resistance and chemical stability are required.

Functional performance mechanisms

Barrier formation
The plate-like particles orient parallel to the substrate during application, forming overlapping layers. This structure significantly reduces permeability to water vapour, oxygen and aggressive chemicals, extending coating and material service life.

Thermal stability
Phlogopite remains stable at temperatures exceeding 900°C, making it suitable for fire protection systems, foundry applications and high-temperature industrial coatings.

Crack control & film integrity
The lamellar structure bridges micro-cracks during drying and curing. In cementitious and coating systems, this reduces shrinkage cracking and improves long-term durability.

Chemical inertness
Phlogopite is chemically stable across a wide pH range and does not release volatiles at elevated temperature. This makes it compatible with common binders, suspension agents and resin systems.

Lubricity and release performance
The smooth platelet surface provides slip and a low coefficient of friction, supporting mould release systems and friction materials.

Vibration and acoustic dampening
The layered mineral structure helps dissipate mechanical energy, contributing to noise and vibration control in automotive and construction applications.

Applications of our mica mineral

Construction and fire protection 

Phlogopite MicaFort plays a key role in fire-resistant construction materials and cement-based systems. 

How phlogopite mica enhances sprayable cement:

• Lamellar particles act as a thermal barrier 
• Stable at high temperature 
• Improves crack resistance during drying 
• Chemically inert within Portland cement systems 
• Provides dielectric insulation properties 

Used for protection of: 

• Steel frames in high-rise buildings 
• Tunnels and underground infrastructure 
• Oil platforms and industrial facilities 

Marine and protective coatings

In marine coatings, the barrier mechanism of phlogopite is particularly valuable. 

When incorporated into a coating film, phlogopite platelets align parallel to the substrate surface. This overlapping structure significantly reduces coating permeability and slows ingress of: 

• Water 
• Salts 
• Aggressive chemicals 

Performance benefits 

• Reduced water vapour transmission 
• Improved corrosion resistance 
• Extended service life 
• Increased resistance to UV and weathering 
• Potential partial or full replacement of micaceous iron oxide 
• Lower coating density compared to MIO 

Applications include: 

• Marine vessel coatings 
• Offshore structures 
• Protective anti-corrosion coatings 
• Heat resistant coatings 

Electrical insulating applications

Phlogopite Mica has long been recognised for its exceptional suitability in mica paper, thanks to its superior electrical and heat insulating properties.

Traditionally, optimised Phlogopite for mica paper has been sourced from locations that are no longer preferred due to sustainability concerns. Latest technology processing techniques combined with mica production knowledge provide a range of high aspect ratio silica free MicaFort Phlogopite Mica products.

European phlogopite mica

LKAB Minerals provides an EU-based Phlogopite source, ensuring that our customers receive RMI Conformant processed Mica.

This product is gaining traction in the industry, as companies are now exploring innovative solutions, such as integrating Phlogopite particles directly into polymers or developing customized mica paper that is ready for use.

Key properties:

• Free of quartz/respirable silica
• Extremely chemical resistant (even concentrated HF and H ₂ SO ₄ )
• Thermostable until 1200°C
• Electrical resistivity up to 1013 Ohms/cm
• Dielectric Strenght up to 10 Volts/cm

Mica paper and tape

Phlogopite MicaFort is well suited to high-temperature electrical insulation applications such as mica paper and mica tape, particularly where end users require mica with verified responsible sourcing.

Mica paper is produced by delaminating mica into fine platelets, forming a flexible sheet material that retains the inherent thermal stability and dielectric strength of the mineral. These sheets are further processed into tapes and laminates for use in demanding insulation systems.

Phlogopite is particularly valued in electrical insulation applications due to:

• Free of quartz/respirable silica
• Chemical resistant, including with concentrated HF and H₂SO₄
• Electrical resistivity up to 10¹³ Ohms/cm
• High thermal stability at elevated temperatures up to 1200°C
• Excellent dielectric strength up to 10 Volts/cm
• Chemical inertness
• Resistance to thermal ageing
• Platelet morphology suitable for paper formation

LKAB Minerals is exploring opportunities to support mica paper and tape manufacturers with high-aspect-ratio phlogopite grades engineered for consistent particle size control and purity.

If you are developing mica-based insulation systems, our technical team welcomes discussion.

Foundry release coatings 

Phlogopite Micafort functions as a refractory filler in zircon-based foundry coatings. 

Performance contribution 

• High thermal stability (up to ~1000°C) 
• No volatile release at casting temperatures 
• Chemically inert in contact with molten metal 
• Reduction of casting defects such as finning 
• Improved balance between barrier performance and gas permeability 
• Controlled drying to reduce film cracking 

The specific gravity of approximately 2.8 allows higher solid loading while maintaining workable rheology. 

Polymers and rubber 

Fine and surface-treated grades provide reinforcement and stability in polymer systems. 

Benefits in polymer compounds 

• Increased stiffness and tensile strength 
• Reduced shrinkage and warpage 
• Improved heat resistance 
• Enhanced dimensional stability 
• Improved matrix bonding with silane-treated grades 

Applications: 

• Thermoset compounds 
• Reinforced thermoplastics 
• Rubber compounds 
• Functional coatings 

Vehicle manufacturing

Phlogopite MicaFort contributes to performance and durability in automotive systems. 

Typical uses 

• Brake pad formulations 
• Tyre mould release coatings 
• Sound and vibration damping components 
• Mould release agents 

In tyre mould coatings, the controlled particle size and top cut reduce nozzle blockage and provide consistent slip and release behaviour. 

Mineral information

Our phlogopite mica mineral is a hydrated silicate of potassium and magnesium.

Grades of MicaFort

 Click the links to download the data sheet for each product.

Physical properties of MicaFort

Grade-specific data is available in Technical Data Sheets. 

MicaFort origin

Phlogopite MicaFort is sourced from a major deposit in Finland and processed in Europe under controlled production conditions.

The Finnish deposit is known for its consistent mineral quality, supporting reliable particle morphology and stable chemical composition, essential for performance-critical industrial applications.

LKAB Minerals provides long-term supply security and full traceability throughout the processing chain.

Toxicology 

Phlogopite mica is a non-toxic natural mineral. 

Quality, processing & sustainability 

Phlogopite MicaFort raw materials are selected from sustainable global sources and processed in Europe under strict quality control procedures. 

LKAB Minerals provides: 

• Controlled particle size distribution 
• High aspect ratio wet-ground technology 
• Precise top cut management 
• Consistent product performance 
• Responsible sourcing practices 

Environmental information

Phlogopite MicaFort is sourced from a facility that is conformant with the Responsible Minerals Assurance Process (RMAP), an independent third-party audit programme developed by the Responsible Minerals Initiative (RMI).

RMAP assesses mineral supply chains against internationally recognised standards, including OECD due diligence guidance.

This conformity provides customers with independent third-party assurance regarding responsible mineral sourcing practices.

LKAB Minerals maintains full traceability and transparency throughout its mica supply chain.The certificate is available on our company information page.

We have a third-party verified Environmental Product Declaration (EPD) for our Finnish mica, which you can view via the link provided here.