Original Article:
A novel way to synthesize calcium sulfate whiskers with high aspect ratios from concentrated calcium nitrate solution
Baozhong Ma, et al.
Materials Letters, 2018, 219, 1-3.
10.1016/j.matlet.2018.02.025
Calcium sulfate (CaSO4) whiskers have excellent physical and chemical properties, such as electrical insulation, heat resistance, high strength and toughness, etc. Among them, hemihydrate CaSO4 and anhydrous CaSO4 can be used as electrical insulator, heat insulator and reinforcing agents for the preparation of high-performance paper, plastics, rubber and ceramics. Compared with the conventional synthesis methods such as hydrothermal method and acidification method, this study developed a relatively low-cost new method for the synthesis of high aspect ratio calcium sulfate whiskers from concentrated calcium nitrate solution. Three single-phase CaSO4 whiskers with high aspect ratios were synthesized in this work.
Concrete synthetic steps include:
> Ca2+ in Ca(NO3)2 solution can react with SO42- in H2SO4 solution to generate CaSO4. Dihydrated CaSO4 whiskers were directly synthesized by adding H2SO4 solution dropwise to abundant concentrated Ca(NO3)2 solution. The aspect ratio can reach 93.5 (length 943.71 μm; diameter 10.09 μm).
> The synthesized dihydrate CaSO4 whiskers transformed into hemihydrate CaSO4 whiskers after microwave heating at 140 ℃ for 5 minutes.
> The synthesized dihydrate CaSO4 whiskers transformed into anhydrous CaSO4 whiskers after heating at 180 °C for 5 minutes.
Chemicals Related in the Paper:
| Catalog Number | Product Name | Structure | CAS Number | Price |
|---|---|---|---|---|
| ACM35054525 | Calcium nitrate hydrate |  |
35054-52-5 | Price |
| ACM10034761-1 | Calcium sulfate hemihydrate |  |
10034-76-1 | Price |
| ACM7778189 | Calcium sulfate |  |
7778-18-9 | Price |
