Utilization of Chrysotile-Type Tailings for Synthesis of High-Grade Silica by Controlled Precipitation

ABSTRACT

This study demonstrates an efficient synthesis of highly reactive silica using hydrometallurgical processing of serpentinite tailings. Proposed process uses two-stage (acid and alkaline) leaching of serpentinite tailings and precipitation of silica from the sodium metasilicate solution using hydrochloric acid. The alkaline leaching and the effect of impurities on the precipitation of amorphous silica under the conditions of maximum sol stability were examined in detail. The proposed route is technologically advantageous because the product did not contain residues of the original raw serpentinite and was characterized by high purity (99.4 wt. % SiO₂), large specific area (541 m² g^–1), and consistent quality. Moreover, less sensitivity to the presence of impurities and longer gelation times, offering a longer time period for manipulating the product in the final stages of the process, were achieved. The total yield of silicon in the overall process was 90–91%.

KEYWORDS:

• Hydrometallurgy
• oxides
• precipitation
• refining
• silicates
• tailings

Funding

This work was supported by the Slovak Grant Agency for Science under Grant 1/0378/14.

Additional information

Funding

This work was supported by the Slovak Grant Agency for Science under Grant 1/0378/14.