Device and method for the thermal treatment of a mineral feedstock

An apparatus for thermal treatment of a mineral starting material, comprising:

• a calciner, including at least a first calciner section and a second calciner section, wherein the first calciner section is arranged vertically, wherein the second calciner section is arranged at an incline, wherein the second calciner section has an angle α between the horizontal and a flow direction of the second calciner section, wherein the angle α is between 20° and 80°, wherein the first calciner section includes a first hydraulic diameter dh,1, wherein the second calciner section includes a second hydraulic diameter dh,2, wherein the second hydraulic diameter dh,2 is less than or equal to the first hydraulic diameter dh,1 multiplied by the sine of the angle α.

The apparatus of claim 23, wherein the second calciner section includes a second starting material feed, wherein the second starting material feed is arranged in a middle region of the second calciner section, wherein the second starting material feed supplies starting material into the gas stream of the second calciner section from above or into the gas stream of the second calciner section from the side.

A process for operating an apparatus for thermal treatment of a mineral starting material, wherein the process is performed in an apparatus comprising a calciner having a vertical first calciner section and an inclined second calciner section, comprising:

• passing a gas stream through the first calciner section and the second calciner section, wherein the hydraulic diameter is four times a quotient of the Froude number flow cross section perpendicular to the flow direction divided by the flow circumference, wherein the Froude number at any point in the second calciner section is equal to or greater than a minimum Froude number in the first calciner section.