Refractory Selection –
Doloma the Preferred Choice

Several types of converter are used for refining stainless steel and today the vast majority of these (> 90 %) are lined with dolomite refractories. This is not only because dolomite represents the lowest cost refractory solution per tonne of steel, but also because it allows the steelmaker to work with highly basic slags which are known to benefit desulphurisation, steel cleanness and metal oxide (chrome) recovery from the slag.

Dolomite refractories not only support desulphurisation but also actively contribute to it. The major requirements for desulphurisation are:

• A low oxygen level in the steel and slag. Dolomite is ideal to fulfil this requirement
  as oxygen would not be picked up from reactions between the bath and refractory
  (due to its low oxygen potential).
• The presence of a highly basic CaO-saturated slag. Such a slag is not only a necessity for efficient desulphurisation, it also happens to be entirely compatible with dolomite refractories, which are lime-bonded.

LWB Refractories has developed a variety of dolomite and mag-dol refractories for use in stainless converters. To realise the best possible performance in terms of lifetime and cost, the lining at each plant needs to be zoned by a combination of brick thickness and composition in order to achieve the optimal design.