For efficient performance of a blast furnace, the extent of reduction of lustite should be

purpose of flux in blast furnace

A. bring down the softening point of the gangue materials

B. reduce the viscosity of the slag

C. to maintain proper basicity

D. all of these

High top pressure in the blast furnace

A. decreases the time of contact between gas and solid

B. increases the time of contact between gas and solid

C. increases fuel consumption

D. increases the rate of solution loss reaction

Dephosphorisation of molten pig iron is favoured by

A. oxidising and basic slag

B. reducing and basic slag

C. high activity co-efficient of phosphorous in metal

D. oxidising and neutral slag

High top pressure in a blast furnace operation

A. favours the solution loss reaction

B. suppresses the solution loss reaction

C. decreases gas-solid contact time

D. increases coke rate