Utilization of lithium slag by wet-grinding process to improve the early strength of sulphoaluminate cement paste

Red mud (RM) is a by-product of extracting of alumina from bauxite. Red mud contains high quantities of alkali-generating minerals and metal ions, which can cause significant environmental damage. Many valuable components such as rare-earth elements, Al, and Fe, in RM are difficult to be utilized owing to their particle size and alkalinity. Thus, developing an economical and efficient technology to consume a large amount of RM can efficiently solve RM disposal issues. This paper systematically reviews the comprehensive utilization methods for reducing RM environmental pollution and divides the comprehensive utilization of RM into three aspects: the effective extraction of valuable components, resource transformation, and environmental application. Based on resource, economic, and environmental benefits, the development of new technologies and new processes with market competitiveness, environmental protection, and ecological balance should be the prerequisite for the low-energy, low-pollution, low-cost, and high-efficiency comprehensive utilization of RM. The direction of future research to solve RM disposal issues is also suggested.

https://www.mdpi.com/2075-163X/9/6/362/pdf

A Review on Comprehensive Utilization of Red Mud and Prospect Analysis

The effect of water and gypsum content on strätlingite formation in calcium sulfoaluminate-belite cement pastes

Improvement of workability and early strength of calcium sulphoaluminate cement at various temperature by chemical admixtures

Research on the preparation and properties of a novel grouting material based on magnesium phosphate cement

Performance and hydration study of ultra-fine sulfoaluminate cement-based double liquid grouting material

The effect of LiAl-layered double hydroxides (LiAl-LDHs) with 3D micro-nano structures on the early properties and hydration process of calcium sulphoaluminate cement (CSAC) clinker was investigated. Three Li Al layered double hydroxides (LiAl-LDHs) with different particle size were prepared through a facile solvothermal method. CSAC clinker incorporating LiAl-LDHs with constant water to cement radio were made and tested. The results indicate that a higher content of LiAl-LDHs resulted in a faster hydration rate, a shorter setting time and a higher early compressive strength. Besides, with the decrease of the particle size of LiAl-LDHs, the hydration rate was accelerated with corresponding increase in compressive strength. However, the influence of particle size of LiAl-LDHs on the setting time of CSAC clinker is not significant. Moreover, the addition of LiAl-LDHs did not result in a new phase formed, but increased the quantity of hydration products providing higher compressive strength and shorter setting time.

Influence of LiAl-layered double hydroxides with 3D micro-nano structures on the properties of calcium sulphoaluminate cement clinker

Sintering red mud based imitative ceramic bricks with CO2 emissions below zero

Synthetic nano CSH is well known to serve as crystal nuclei in ordinary Portland cement . In this paper, tartaric acid was used as a stabilizer to prepare nano CSH by a separate nucleation and growth steps method. The acquired samples were tested by XRD , FT-IR, TG-DSC, total organic carbon (TOC) and dynamic laser scattering (DLS) and their effect on hydration and hardening of ordinary Portland cement were investigated. The results indicated that tartaric acid intercalated the interlayer regions of CSH, and swelled the interlayer spacing from 1.288 nm to 1.398 nm. The average particle size of the CSH-tartaric acid nanocomposites（CTNs）were in the range of 60–160 nm, and increasing the concentration of tartaric acid in composites caused a smaller CTNs particle size. When present in the alkaline solution of pH 13, tartaric acid can be released from CTNs, and the higher concentration of tartaric acid in the CTNs, the more tartaric acid was released. Due to the synergistic effect of nanocrystal nucleus and tartaric acid released from CTNs, the total hydration heat declined at first and then increased and the pore structure of hardened pastes was adjusted, resulting in the increase of compressive strength at all ages. • CTNs were prepared by a separate nucleation and growth steps method. • Increasing the concentration of tartaric acid in composites caused a smaller CTNs particle size. • Tartaric acid can be released from CTNs in the alkaline solution of pH 13. • Cement hydration was affected by both nano crystal nucleus and tartaric acid released from CTNs. 

Effects of synthetic CSH-tartaric acid nanocomposites on the properties of ordinary Portland cement

In our previous study, ultrafine ettringite was prepared in the presence of citric acid by using a nucleation and aging separation method. Due to the seed effect, ultrafine ettringite enhanced the hydration rate and compressive strength of sulfoaluminat cement-based materials at all ages. However, when the particle size of sulfoaluminat cement-based materials became smaller, ultrafine ettringite retarded the hydration rate of ultrafine sulfoaluminat cement-based materials (USCM). In this paper, ettringite was prepared under different citric acid concentrations and characterized by XRD, FT-IR, TG-DSC, PSD and TOC measurements. The effect of ettringite on the properties of USCM was experimentally studied. Results showed that citric acid can absorb on the surface of ettringite. The average particle size of the citric acid-ettringite composites（CECs）were in the range of 100–300 nm, and increasing the concentration of citric acid in composites lead a smaller size of CECs. When present in the alkaline solution of pH 13, the higher citric acid concentration used in the preparation of CECs, the more amount of tartaric acid released from CECs. CECs retarded the cement hydration, modified the pore structure and enhanced the compressive strength of USCM pastes at all ages due to the synergistic effect of nano crystal nucleus and citric acid released from CECs.

Haiyan Li

Papers

Performance and hydration study of ultra-fine sulfoaluminate cement-based double liquid grouting material

Influence of LiAl-layered double hydroxides with 3D micro-nano structures on the properties of calcium sulphoaluminate cement clinker

Sintering red mud based imitative ceramic bricks with CO2 emissions below zero

Effects of synthetic CSH-tartaric acid nanocomposites on the properties of ordinary Portland cement

Synergy effect of synthetic ettringite modified by citric acid on the properties of ultrafine sulfoaluminat cement-based materials