What are the two ways to form the carbonates?
Sedimentation (chalk)
Mineralisation (limestone)
(marble formed from either by extremely high pressure and temperature
what is mineralisation?
calcium bicarbonate is precipitated and compressed to form limestone deposits
what is sedimentation process
sea animal shells and skeletons fall to floor where they are compacted to form chalk
how are the 3 calcium carbonates formed
Chalk - sedimentation
limestone - mineralisation (precipitation of calcium bicarbonate)
marble - extreme temp + pressure with either of two previous forms
what features are often present in GCC SEM images?
coccolith (shell structure)
What is calcium carbonate an example of
a polymorph -same chemical formular but different crystal structure. calcite, aragonite and dolomite
what are the polymorphs of calcium carbonate
calcite most common
aragonite
dolomite
if surface energy is low is the mineral hydrophobic or hydrophilic?
hydrophobic
PCC process
Limestone –> brunt (CaO) –> mixed with water (limeslacking) –> Co2 bubbled in to form CaCO3 (precipiation).
you then screen and thicken
Advantages of PCC vs GCC
Bulk
Opacity (Because narrow PSD remove ultra fine)
Brightness
Caliper
Disadvantages of PCC vs GCC
high porosity (can be good in some applications)
lower strength
water and ink absorption
