Products & Services

Doloma bricks and monolithics
Dolomite Franchi supplies its products worldwide, having Italy as main market.
Refractory products based on burnt dolomite are mainly used for the steelmaking industry:
thanks to their extremely low rate of impurities the bricks are suitable for the refractory linings of casting and treatment ladles as well as for the refractory linings of AOD converters,
the mixes, mainly serve as auxiliary material for the bricks, but also for the construction and repair of the hearth of electric arc furnaces.

Mining and treatment of raw materials

The raw material is an extremely pure dolomite, CaCO₃.MgCO₃. The dolomite is strip mined in Calarusso, an open pit mine located to few hundred meters from the plant. At the current production level, the dolomite deposit will yield raw material for another 30-40 years. From the mine, the crushed dolomite rock is taken to the production plant by means of a cable way. The crude material is then treated in the shaft sintering kilns at high temperatures (approx. 1.900°C) to obtain high-density doloma, CaO.MgO. The selected doloma is the basic material for the production of bricks and mixes.

Bricks
Ladle
Currently doloma bricks are used as refractory lining of treatment and casting ladles in many steelplants worldwide. The DOLOMITE FRANCHI Pentabrick lining, thanks to its low oxidation potential, does not transfer oxygen to the liquid steel: therefore it makes desulphurisation easier, it is highly compatible with basic slag, it increases the yield of Fe-alloys and can grant long service life at lower refractory costs.

AOD Converter and VOD Ladle
The AOD and VOD processes are nowadays the most common ways to produce stainless and alloy steel grades. Doloma and mag-doloma refractories are considered the standard lining for such a metallurgical process, especially for their attitude to desulphurisation, to work with silica based slag and to achieve the best performance in terms of costs and service life. RHI, with DOLOMITE FRANCHI, offers a wide range of fired and C-bond doloma based bricks, suitable for most of the metallurgical treatments.

Mixes
Electric Arc Furnace
The Pentasol mixes of DOLOMITE FRANCHI contain 40-50% of CaO. They are suitable for the construction and repair of the hearth and the bank of EAFs not particularly stressed, where the Fe-oxide content is low and the slag basicity is good. A better performance of Pentasol is achieved when it is well de-aired and rammed. Thanks to their grainz size distribution Pentadol mixes, are suitable for hot repair of the hearth and the slag door and to fill the taphole of EAFs equipped with traditional launders.

Ladle - AOD
Doloma mixes play a very important role in ladles and AOD refractory linings: they fill the gaps that the bricks cannot line and, at the same time, they offer the necessary resistance and reliability. Pentaram and Pentaplast are plastic ramming mixes, mainly used for the ramp of the ladle sidewall lining (spiral system), for filling the gaps around the bottom, around the well block/seating block, behind the tuyere bricks and for sealing the top of the lining. Pentamix and Pentafill mainly need to fill the gap between working and safety lining.

Packing
As doloma refractories are a CaO based material, packing is an essential component to protect it against dampness. If the CaO of doloma is exposed to damp air without any protection for a long time, it reacts with the atmospheric moisture and forms calcium hydroxide Ca(OH)₂ that damages the properties of doloma refractories. Proper packing ensures that DOLOMITE FRANCHI products reach the customers at any latitude in the same good condition as when they left the production plant.

Technical Assistance

Technical Assistance is a fundamental part of the DOLOMITE FRANCHI as it allows customers to obtain the best results at the lowest possible costs from their ladles:

Optimisation of ladle operational practice
Slag optimisation and control
Advice in lining balancing
Assistance with lining construction