CALCINED DIATOMITE PRODUCTS WITH LOW CRISTOBALITE CONTENT
Disclosed herein is a flux calcined diatomite composition having a cristobalite content of less than about 5% by weight relative to the total weight of the flux calcined composition and a whiteness of greater than about 90. Also disclosed herein is a process for producing flux calcined diatomite compositions comprising calcining a feed composition comprising diatomite having an iron content of at least about 0.5% by weight relative to the total weight of the feed composition in the presence of at least one flux comprising at least one alkali metal.
1 - 82 . (canceled)
83 . A calcined diatomite composition having a cristobalite content of less than about 5% by weight relative to the total weight of the composition and a whiteness of at least about 90.
84 . The composition of claim 83 , wherein the cristobalite content is less than about 2% by weight relative to the total weight of the composition.
85 . The composition of claim 83 , wherein the cristobalite content is less than about 1% by weight relative to the total weight of the composition.
86 . The composition of claim 83 , wherein the cristobalite content is less than about 0.5% by weight relative to the total weight of the composition.
87 . The composition of claim 83 , having a whiteness of greater than about 91.
88 . The composition of claim 83 , having a whiteness of greater than about 93.
89 . The composition of claim 83 , wherein the composition has been flux calcined in the presence of at least one flux comprising at least one alkali metal chosen from potassium, rubidium, and cesium.
90 . The composition of claim 83 , wherein the composition has a mean diameter of less than about 40 μm.
91 . The composition of claim 83 , wherein the composition has a mean diameter of less than about 20 μm.
92 . The composition of claim 83 , wherein the composition has a mean diameter of less than about 10 μm.
93 . The composition of claim 83 , having a d 90 of less than about 50 μm.
94 . The composition of claim 83 , having a d 90 of less than about 20 μm.
95 . The composition of claim 83 , having an iron content of less than about 0.5% by weight relative to the total weight of the composition.
96 . The composition of claim 83 , having a Hunter a value of less than about 1.
97 . The composition of claim 83 , having a Hunter b value of less than about 8.
98 . The composition of claim 83 , having a Hunter b value of less than about 4.
99 . A process for producing a calcined diatomite composition having a cristobalite content of less than about 5% by weight relative to the total weight of the composition and a whiteness of greater than about 90, comprising calcining a feed composition comprising diatomite having an iron content of less than about 0.5% by weight relative to the total weight of the composition.
100 . The process of claim 99 , wherein the feed composition is flux calcined in the presence of at least one flux comprising at least one alkali metal.
101 . A flux calcined diatomite composition having a cristobalite content of less than about 5% by weight relative to the total weight of the composition and an iron content of less than about 1% by weight relative to the total weight of the composition.
102 . The composition of claim 101 , wherein the cristobalite content is less than about 1% by weight relative to the total weight of the composition.
103 . The composition of claim 101 , having a whiteness of greater than about 90.
104 . The composition of claim 101 , having a whiteness of greater than about 92.