Dolomite monolithics

The monolith catalysts are the least tested in pilot scale, however they have the advantage that they offer good mechanical strength and have high catalytic activity. On the other hand their cost is considerably higher and they arc more prone to poisoning and deactivation than dolomite and related catalysts. Because of their cost, the most important operational variable is the life of the catalyst. 

Dead-burned dolomite is used in the production of refractory bricks, shaped refractories and for monolithic refractories. High purity, low iron dolomite for brickmaking is generally sintered at temperatures of 1800 °C or higher (see section 16.9). A lower purity product (which is often pre-blended with 5 to 10 % of iron oxide to assist sintering) is used for fettling purposes. It is sintered at 1400 to 1600 °C. 

Cupola. A shaft furnace used in a foundry for the melting of iron. Cupolas are generally lined with fireclay refractories covered with a ganister-clay mixture. For the production of cast iron with a low sulphur content, a basic lining is sometimes used the lining is in this case built of chrome-magnesite or dolomite refractories, or it may be rammed with a monolithic basic refractory composition. 

The cost of the lining amounts to between 1 and 2% of the cost of construction if the rate of consumption of refractory material is about 0.5-1.5kg per tonne of Portland cement clinker produced. About 35% of the lining in a modern kiln typically consists of dolomite brick, 35% of magnesite-chrome brick, and the remainder (30%) of fireclay brick, lightweight refractory brick, special brick and monolithic refractories. 

Carbon, not only classifies by refractory type, but also by MgO content or principal oxides content this classification is shown in Table 10 (52). ISO 1927-1984 covers the ISO classification for dense and insulating monolithic refractories Class IV applies to basic materials, but, like the SIC standards, this standard uses only general types of products with differentiation within the class limited to the principal basic material of the monolithic mixtures—magnesia, chrome ore, spinel, forsterite, dolomite, or other alkaline earth oxides (53). 

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