| 摘要 |
#CMT# #/CMT# Producing filler or coating pigment for paper- or cardboard production, from thermally treated solids, which are: prepared from calcium and kaolin; are thermally treated in a combustion process at 600-850[deg] C, preferably 700-780[deg] C; discharged with a gas stream that is removed from the combustion process; and are separated from the gas stream in a filter unit, comprises suspending the separated thermally treated solids in water or aqueous solution, and passing the obtained suspension through a carbon dioxide-containing gas (5) or spraying the suspension into the carbon dioxide-containing gas. #CMT# : #/CMT# Producing filler or coating pigment for paper- or cardboard production, from thermally treated solids, which are: prepared from raw materials comprising calcium and kaolin; are thermally treated in a combustion process at 600-850[deg] C, preferably 700-780[deg] C; discharged with a gas stream that is removed from the combustion process; and are separated from the gas stream in a filter unit, comprises (a) suspending the separated thermally treated solids in water or aqueous solution, and (b) passing the obtained suspension through a carbon dioxide-containing gas or spraying the suspension into the carbon dioxide-containing gas exhibiting a carbon dioxide content of at least 5 vol.%, based on dry gas. #CMT#USE : #/CMT# The filler or coating pigment is useful for paper- or cardboard production (claimed). #CMT#ADVANTAGE : #/CMT# The method makes use of kaolin and calcium as the raw materials, which are obtained from waste sludge that is obtained during waste paper processing. The filler or the coating pigment exhibits less reactivity with water, and can be easily stored or transported as an aqueous suspension. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a schematic representation of a system for producing the filler or the coating pigment. 1 : Hopper 2 : Blower 5 : Carbon dioxide-containing gas 6 : Carbon dioxide-reactor 9 : Mixing tank of a paper machine 10 : Process water container #CMT#INORGANIC CHEMISTRY : #/CMT# Preferred Method: The combustion process is carried out in a fluidized bed having a temperature of 600-850[deg] C, preferably 700-780[deg] C. The steps (a) and/or (b) are carried out in a flow reactor, which generates high turbulence and high shear forces in the suspension. The step (b) is carried out in a carbon dioxide-reactor and/or the flow reactor at an increased pressure, preferably at 2-12 bar excess pressure, preferably 4-6 bars excess pressure. The suspension is concentrated after the step (b) or at the end of the step (b), or after the step (a) or at the end of the step (a) until the suspension exhibits solids content of 30-80%, preferably 40-70%. The concentrated filler suspension is supplied to a mixing tank of a paper- or cardboard production machine, comprising a fibrous-filler suspension, without intermediate storage. The concentration of the suspension after the step (b) or at the end of the step (b), produces process water, which is separated and recirculated into the suspension before the step (b) and/ or (a). The concentration of the suspension after the step (a) or at the end of the step (a), produces process water, which is separated and recirculated into the suspension before the step (a). The method comprises adding acid, preferably, sulfuric acid after the step (a) and before supplying the carbon dioxide-containing gas to the suspension. The step (a) further comprises oxidatively bleaching using peroxide. The step (b) further comprises reductively bleaching using dithionite. Preferred Components: The carbon dioxide-containing gas exhibits a carbon dioxide content of 10-50 vol.%, preferably 10-30 vol.%, based on the dry gas. The carbon dioxide-containing gas is a flue gas of combustion, which is derived from the combustion process for the thermal treatment. #CMT#EXAMPLE : #/CMT# No suitable example given. |
