Study of Semi-Dry High Target Solidification/Stabilization of Harmful Impurities in Phosphogypsum by Modification.

Fenghui Wu,Can Yang,Liangliang Liu,Junyan Li,Yuanchuan Ren,Shan Liu,Guangfei Qu,Bangjin Chen,Yuyi Yang

doi:10.3390/molecules27020462

Abstract

Phosphogypsum (PG) treatment is one of the research hotspots in the field of environmental protection. Many researchers both at home and abroad have devoted themselves to studies on harmless resource treatment of PG, but the treatment technology is unable to meet the demand of PG consumption due to the huge production and storage demands. In order to solve the problem of PG pollution, this study explored the different solidified effects of various modification formulations on the hazardous components in PG, using industrial solid waste calcium carbide slag (CCS) as an alkaline regulator; Portland cement (PC), polyaluminum chloride (PAC) and CaCl2 as the main raw materials of the solidification and stabilization formula and the water content in PG as the reaction medium. The results showed that CCS (0.5%), PC (0.4%) and PAC (0.3%) had a more significant solidified effect on phosphorus (P) and fluoride (F). PAC was added in two steps and reacted under normal temperature and pressure, and its leaching toxicity meets the requirements of relevant standards, which laid an excellent foundation for PG-based ecological restoration materials and filling materials, with low economic cost, simple process and strong feasibility. This will provide great convenience for the later mining and metallurgy.

Highlights

With increased attention being paid to the world’s ecological environment, various policies and regulations on environmental protection have been issued [1,2]
The purity of phosphoric acid mainly depend on the grade of phosphate rock [6]
There will be increasingly relevant requirement levels of PG disposal, in most cases without pretreatment, which can cause serious environmental contamination due to impurities. This contamination may result from the heavy metal, phosphorus (P) and fluoride (F) [7,8] attached to the surface of the calcium sulfate dihydrate crystal, fluorine-containing phosphorus crystal water [9,10,11], capillary water and attached water

Summary

Introduction

With increased attention being paid to the world’s ecological environment, various policies and regulations on environmental protection have been issued [1,2]. Mineral resources are gradually depleted, showing a gradual decrease in high-grade ores [6], but the yield of PG and the purity of phosphoric acid mainly depend on the grade of phosphate rock [6]. With the gradual decrease in phosphate rock grade, the unit production of PG will gradually increase [6]. There will be increasingly relevant requirement levels of PG disposal, in most cases without pretreatment, which can cause serious environmental contamination due to impurities. This contamination may result from the heavy metal, phosphorus (P) and fluoride (F) [7,8] attached to the surface of the calcium sulfate dihydrate crystal, fluorine-containing phosphorus crystal

Methods

Results

Conclusion