Coral sand from hydraulic reclamation for the remediation of acid sulfate soil

Abstract

For the first time, Coral sand, as the main geotechnical material in reclamation, has the characteristics of loose and porous structure, relatively small volume and mass, easy to break and high compression, and high calcium carbonate, which may be a natural material to control acid release of acid soil. In this paper, by studying the neutralization effect of coral sand under different sand ratio, particle size and adding methods, the optimal dosage and particle size of coral sand and the adding sequence were determined under typical acid soil conditions; The neutralization performance of different neutralizing materials was compared through internal structure characterization, and the structural advantages of coral sand were explored. The results show that the specific surface area of coral sand was 1.2361m2g-1, second only to calcite and shell powder. The particles were evenly distributed and can fully react with sulfuric acid to produce CaSO4 precipitation. When the addition of coral sand was 9% (Ca: S = 18:5), the PASS can be neutralized to pH > 6.5. The PASS neutralization ability of coral sand was related to particle size. The overall trend was that the smaller the particle size, the stronger the neutralization ability. The best effect was at 0.15mm, when the particle size exceeded 0.27mm, the neutralization ability began to decline.