Figure 4.

Intensity of the main peak of wollastonite (d = 0.2980 nm) in XRD patterns of calcined products. Hydrothermal synthesis temperature: a – 95 °C, b – 130 °C, duration: ○ – 0 h; ● – 4 h, ■ – 8 h, ◆ – 12 h, □ – 24 h, ◊ – 36 h, ▲ – 48 h.