What is stone wool and how is it obtained?

Unlike other types of insulation materials, stone wool is the only thermal insulation material that simultaneously provides thermal, acoustic and fire protection of buildings.

Stone wool insulation ensures energy savings and the money you invested in insulation wil be returned within several years – which makes your return on investment extraordinary! Using a state of the art technology, Knauf Insulation manufactures a wide range of top quality stone wool products for diverse applications: pitched and flat roofs, external, internal and partition walls, floors on the ground and mezzanine floors. Knauf Insulation stone wool is waterproof, vapour-permeable, resistant to chemicals and microorganisms, durable, it does not enhance the growth of bacteria and moulds and it is recyclable.


Stone wool is an insulation material of inorganic origin intended fort hermal and acoustic insulation, as well as for fire prevention in civil engineering, industry and the shipbuilding industry. Raw materials used for the production of stone wool are stone of volcanic origin (diabase and dolomite, and in lesser extent basalt) and so-called briquettes (obtained by the recycling of technological process waste with the addition of cement – such a recycling provides a closed circle of recycling and waste).

1. Major chemical compounds included in the composition of the mentione draw materials are oxides of silicon, aluminium, calcium, magnesium and iron. In accordance with formulations, the raw materials are added in a cupola furnace where they are melted at a temperature above 1400°C. In this raw material melting process, coke is used as an energy source. As an additional energy source, oil is used for the incineration of flue gasses.

2. With an up-to-date flue gasses purification system, dust and carbon monoxide are eliminated, while a great part of energy returns to the production process. The mass obtained in the melting process in the cupola furnace is brought to the wheels of a centrifuge where this mass is unraveled into fibers.The centrifuge wheels break the mass into drops; through the wheels, air is blown in to stretch the obtained drops into fibers. Through a mist of yarn, the fibers are blown into a collecting chamber and this is how primary felt of stone wool is obtained.



Primary felt prior to entering the polycondensation chamber

3. Primary felt then reaches a wool precipitation system – the so-called pendulum system that enables achieving excellent insulation characteristics by providing a uniform distribution of fibers and high level of their intertwinement, thus providing more space for »air retention«, which is one of the most important conditions for insulation material functioning

4. In the polycondensation chamber, the process of polycondensation or binder fixing is carried out which together with fiber binding provides technical characteristics of the product. The process is carried out at 270°C with water evaporation and fixing of the binder added in the mass unraveling phase. All flue gasses are incinerated and purified, thus closing the circle of flue gasses release.



Felt entering the polycondensation chamber

5. The chamber process is followed by cutting of final products in to required dimensions, their stacking and packaging.

Cuttingof slabs into required dimensions


Completed production process and closed recycling circle.


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