Chemical Knowledge 11:PCC OR GCC
Update time: 26-04-14 Views: 3
PCC OR GCC
01In terms of specific surface area, the specific surface areas of 1000 mesh ground calcium carbonate（GCC）and precipitated calcium carbonate（PCC）are about 4.5, which seems to be equivalent in unit mass of powder. However, the two are quite different in performance, as if fire and water cannot be tolerated. One notable difference is agglomeration. The agglomeration of PCC is strong, while that of GCC is relatively low. This raises a question: what index can we use to quantify the agglomeration of powders?Delving deeper, is agglomeration related to the structure of the powder surface? This question deserves further exploration, as agglomeration affects product dispersion and performance.
02 In terms of specific surface area and performance comparison, precipitated calcium carbonate (PCC) is produced through chemical purification methods. Firstly, limestone is heated to high temperatures to convert it into quicklime, which is then hydrolyzed to produce calcium hydroxide. Subsequently, a carbon dioxide precipitation reaction is utilized to produce fine calcium carbonate powder in the aqueous phase, typically with a particle size of less than 12 microns. In contrast, ground calcium carbonate (GCC) is produced by physically grinding ores such as calcite, marble, and limestone into specific powder forms. These two types exhibit significant differences in appearance: PCC has a spindle-like shape, while GCC has an irregular shape. However, at the micron-scale particle level, this appearance difference does not seem to have a significant impact on performance.
03 The Mystery of Oil Absorption Value: Oil absorption value is another crucial indicator. The oil absorption value of light calcium carbonate (LCC) is significantly higher than that of heavy calcium carbonate (HCC), with the latter being only 1/3 to 1/4 of the former. Despite having similar specific surface areas, this substantial difference raises a question: who is secretly "stealing oil"? This is closely related to coatings or structural adhesives. For instance, 107 adhesive is expensive, but powders with low oil absorption values often exhibit good fluidity. However, there are exceptions. Some HCC powders have oil absorption values close to those of aragonite, yet their fluidity is inferior to that of marble powder. Why is this?
04 In terms of plasticization, when light calcium carbonate is filled into PVC, the plasticization speed is fast, the current is high, and the final molded embryo has a higher glossiness. However, the plasticization speed of heavy calcium carbonate is slower, the current is lower, and naturally, the glossiness of the molded embryo is inferior to that of light calcium carbonate. Why do these two materials, which seem to have similar specific surface areas, exhibit such significant differences in practical applications? We need to conduct more in-depth research on this.
After considering the above issues, the summary is as follows:
01: Structure determines performance: Physical properties are the foundation, and chemical analysis can help us understand them more clearly.
02: Correlating powder structure and performance: Clarifying the relationship between the two will reveal the potential value of some products.
03: Impact of Surface Differences: The surface structures of light calcium carbonate and heavy calcium carbonate differ significantly, but when they reach a certain fineness, their properties may converge. Economic factors are another dimension to consider.
