Perlite is a natural volcanic glass. There are many natural volcanic glasses around the world but the key feature for perlite is that when it is heated it expands. The expansive process is a lot like making pop corn. The resultant expanded perlite can be 20-30x its original bulk density. The process of expansion targets the combined water content within the raw perlite - the water trapped in the perlite ore - which vaporizes under heat and creates a glass bubble.

The expansion process normally takes place at when the perlite ore is rapidly heated to approximately 800-850˚C. For an ideal process, a combined water in raw perlite of 2.77-3.25% would be targeted. The resultant popped or expanded perlite, which is like a glass bubble, has extremely good insulating properties and is light weight. Expanded perlite can be engineered to a range of weights depending on the final application. This can range from 32-240kg/m3.

Perlite Ore Blue Pacific Minerals

For cryogenic insulation, for example, loose bulk densities can range for a cold box from 40-48kg/m3 which when considering an unexpanded perlite ore density of 1000-1100kg/m3 is quite a remarkable achievement. Blue Pacific Minerals produces perlite ore which is known to achieve the example loose density mentioned above in factory expansion situations as well as through portable on site expansion plants.

Once the perlite is expanded and has intrinsic characteristics of excellent insulation and light weight there are a number of potential applications. Expanded perlite can be used in the manufacture of low temperature (cryogenic) and high temperature insulation (formed and loose products), lightweight insulating concrete, lightweight insulating board, lightweight insulating plasters, and wall insulation.

Applications: Cryogenic Insulation

Perlite for Cryogenic Insulation3The unique insulating role of expanded perlite is characterised by a combination of its low thermal conductivity, excellent thermal properties and light weight. This has enabled expanded perlite to become an accepted material for the insulation of vessels and pipe work involved with -

  1. liquefied gas storage vessels - ammonia, nitrogen, etc
  2. gas tankers including LNG tankers
  3. cold boxes in oxygen production / air separation units

The cryogenic classification of the insulation being based on the fact that the storage vessels are maintained at -100ºC and below.

Blue Pacific Minerals perlite has been independently tested for its thermal conductivity. The expanded perlite sample, that had been expanded by a mobile perlite expansion operation in Australia, was tested by BRANZ (NZ). The results were conducted at 0˚C and the conductivity result was 0.0381 W/mK with a compacted density of 53.92kg/m3. This confirms the suitability of Blue Pacific Minerals perlite for cryogenic applications.

The raw perlite ore Blue Pacific Minerals offers comes in a range of grades. A grade can also be custom manufactured to meet specific client requirements. With its ‘youthfulness' compared to other perlite sources in the world Blue Pacific Minerals perlite tends to have a lower expansion temperature requirement driving down per unit costs for the expanded ore. The lower expansion temperature combined with greater expansion ratios makes the perlite ore highly prized among expander operations. This is especially the case for remotely located mobile- portable expansion plant operations.

Blue Pacific Minerals has supplied cryogenic perlite ore to remote expansion operations in Australia, South East Asia and the Middle East. These sites value the reliability and repeatability of the perlite ore Blue Pacific Minerals offers.


Perlite Foundry Blue Pacific MineralsThe insulating property of our New Zealand perlite makes ore type suitable for use in steel and foundry industries.
As well as insulating, the perlite combines with the slag in the melt to aid in the practical removal of the impurities.  Besides aiding the melt slag removal residues, the perlite helps to extend the life of the refractory liner.
The perlite Blue Pacific Minerals has to offer to the steel and foundry sector has been created to ensure the ideal impact in the melt situation.
By working with our clients we are focused on continual improvements. 

Available in 1m3 Bulk or 25kg bags.


Blue Pacific Minerals NZ Perlite Quarry