Mechanical Performance of the Phosphogypsum Baking-free Bricks

Title:Mechanical Performance of the Phosphogypsum Baking-free Bricks

Volume: 14 Issue: 2

Author(s): Xiaoyu Guo, Yajing Mao, Lizhai Pei*Chuangang Fan

Affiliation:

• Key Laboratory of Metallurgical Emission Reduction & Resources Recycling, Ministry of Education, School of Materials Science and Engineering, Anhui University of Technology, Ma’anshan, Anhui 243002,China

Keywords: Phosphogypsum, baking-free bricks, mechanical performance, X-ray diffraction, scanning electron microscopy, cementing materials.

Abstract:

Background: A large amount of phosphogypsum occupies the land and causes environmental pollution. It is of great research significance and urgency to the utilization of the phosphogypsum.

Methods: The influence of the ratio of the cementing materials and phosphogypsum (C/P ratio) on the compressive strength, water absorption, softening coefficient and freeze-thaw stability of the phosphogypsum baking-free bricks was investigated. The consolidation process of the phosphogypsum baking-free bricks was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Results: XRD patterns show that the phosphogypsum baking-free bricks curved for 28 d are mainly composed of monoclinic CaSO₄·2H₂Oand hexagonal Ca6Al₂(SO₄)₃(OH)₁₂·26H₂O (Aft) phases. SEM observation shows that the phosphogypsum bricks consist of Aft nanorods and irregular microscale particles. The softening coefficient, water-resistant performance and freezethaw stability of the phosphogypsum baking-free bricks remarkably decrease with decreasing the C/P ratio. 28 d compressive strength decreases from 26.42 MPa to 15.58 MPa with the change of the C/P ratio from 1:1 to 1:2.5. The optimal ratio of the cementing materials and phosphogymsum is 1:1. The phosphogypsum baking-free bricks exhibit good stability after 18 freeze-thaw cycles.

Conclusion: Phosphogypsum baking-free bricks were prepared by natural curing process using phosphogypsum as the raw materials, cement, slag, fly ash and silica fume as the cementing materials. The phosphogypsum baking-free bricks exhibit great application in the field of building materials.

Cite this article as:

Guo Xiaoyu , Mao Yajing , Pei Lizhai *, Fan Chuangang , Mechanical Performance of the Phosphogypsum Baking-free Bricks, Current Materials Science 2021; 14 (2) . https://dx.doi.org/10.2174/2666145414666210203115332