Study on the high temperature hydration characteristics of titanium extraction slag cementing fluid

Abstract

Titanium extraction slag (TES) is the residual tailings of high titanium blast furnace slag after secondary titanium extraction, mainly composed of silicoaluminate glass body and crystal impurities such as FeO and TiC. The special chemical composition makes the activity of TES lower than that of granulated blast furnace slag (GBFS), resulting in a large amount of accumulation and causing serious resource waste and environmental pollution. This article preliminarily explores the feasibility of using TES in oil and gas well cementing engineering with reference to underground temperature curing TES. The optimal compressive strength was obtained at a curing temperature of 70 ℃, with a 3 d strength of 15.78 MPa, which not only meets the requirements of cementing engineering but also exceeds the strength of GBFS under the same conditions. At the same time, based on the composition and structural changes of hydration products cured at 70 ℃ for 3 and 28 d, and analyzes the hydration mechanism of TES at high temperatures. The results showed that under the influence of strong alkali activation and CaCO3 nucleation, TES rapidly hydrated and almost completely hydrated at 3 d. As hydration progresses, C-A-S-H crosslinks with each other and gradually transforms into a more dense and thermally stable crystal form (Foshagite), allowing for continuous improvement in compressive strength within 28 d. In summary, TES has high activity at high temperatures, and the strength of the solidified body meets the requirements of cementing, making it suitable as a cementing material for well cementing.