General Requirements on refractory
The desirable characteristics of refractory which must be achieved by careful selection are:

  • Refractoriness – i.e. the ability of the brick to retain its physical properties at the operating temperature;
  • Volume stability – i.e. no excessive expansion;
  • Chemical resistance – i.e. resistance to the attacking species in the feed and kiln atmosphere in the zone in question;
  • Abrasion resistance;
  • Low thermal conductivity;
  • Coatability – in general a porosity or surface texture allowing the clinker liquid to “glue” coating to the surface.

Today’s challenges on refractory
Increased usage of AFRs and Petcoke
  • Higher load on circulating elements (Cl, SO3, alkalis) in the kiln system
  • Less favorable combustion conditions (local reducing conditions, fluctuations in heat input, less stable kiln operation,…)
  • More variable flame (shape) due to a more variable fuel mix (AFRs) resulting in shifting burning zone and less stable coating
Decreasing clinker / cement factor requires a more reactive clinker, having higher LSF and SR targets
  • More burning effort required
  • Less protective coating in the burning zone
Forced operation above nominal rate
  • High thermal load in the burning zone or calciner

Holcim Objectives regarding Refractories

Net Kiln availability of ³  90%:
  • Maximum one kiln stop per year for refractory replacement (required downtime: 21 + 6 + 10 days)
Acceptable variable cost from refractory:
  • Specific refractory consumption (g / kg cli) according or below best practice:
         < 400 g/t for calciner kilns
         < 800 g/t for preheater
         < 1200 g/t for long kilns
Acceptable fixed cost from refractory:
  • Installation of a durable refractory quality at a reasonable cost for all new kiln lines and kiln upgrades
  • Fast and efficient installation methods

(Source : Holcim)

Materials list and usage 


 Compiled by Cost Solutions Company Limited