Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter 66.4.5 Spar calcinationDescription25 % of the total fuel is used in a separate burner for the fluorspar feed calcination process. Thespar is heated to approximately 400 °C by countercurrent contact with flue-gases at atemperature of approximately 900 ºC. The gases exit the calcinator at approximately 110 °C.Relatively small kiln dimensions are needed because of the high energy input into the feed tothe rotary kiln.Achieved environmental benefitsNo SO 2 is produced by the reaction of the flotation chemicals with sulphuric acid.Cross-media effectsEmission of approximately 2 to 5 % of the flotation chemicals as organic carbon in the form ofcracked products.Operational dataNo specific information provided.ApplicabilityDue to the high reactivity of the very hot spar, the reactants must be sent to the kiln directlywithout going to a pre-reactor. The advantages of a pre-reactor are consequently missing, forinstance, the process is quite sensitive to feed ratio variations and acid concentrations, whichmay in turn cause heavy kiln scaling.EconomicsThe investment cost for spar calcination is approximately 50 to 100 % higher than for the prereactor.This may be partially compensated for by lower fuel consumption and lowermaintenance costs in comparison to the pre-reactor.Driving force for implementationIncreasing plant capacity for an existing kiln.References to literature and example plants[22, CEFIC, 2000]272 Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers