Morphology of Barite Synthesized by In-Situ Mixing of Na₂SO₄ and BaCl₂ Solutions at 200 °C

• Main Authors: Chunyao Wang, Li Zhou, Shuai Zhang, Li Wang, Chunwan Wei, Wenlei Song, Liping Xu, Wenge Zhou
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Crystals
• Subjects: Barite; hydrothermal synthesis; typomorphic characteristics; in-situ mixing solutions at high temperature
• Online Access: https://www.mdpi.com/2073-4352/11/8/962

Barite is an abundant sulfate mineral in nature. Especially, the variety of morphologies of barite is often driven by the mixing of Ba-bearing hydrothermal fluid and sulfate-bearing seawater around hydrothermal chimneys. In order to better understand the factors affecting the morphology and precipitation mechanism(s) of barite in seafloor hydrothermal systems, we synthesized barite by a new method of in-situ mixing of BaCl₂ and Na₂SO₄ solutions at 200 °C while varying Ba concentrations and ratios of Ba²⁺/SO₄²⁻, and at room temperature for comparison. The results show that barite synthesized by in-situ mixing of BaCl₂ and Na₂SO₄ solutions at 200 °C forms a variety of morphologies, including rod-shaped, granular, plate-shaped, dendritic, X-shaped, and T-shaped morphologies, while room temperature barites display relatively simple, granular, or leaf-like morphologies. Thus, temperature affects barite morphology. Moreover, dendritic barite crystals only occurred at conditions where Ba²⁺ is in excess of SO₄²⁻ at the experimental concentrations. The dendritic morphology of barite may be an important typomorphic feature of barite formed in high-temperature fluids directly mixing with excess Ba²⁺ relative to SO₄²⁻.