Optimization of calcination and stabilization technology for heavy metal contaminated soil

Heavy metal-contaminated soil poses a threat to both the environment and human health, and there was an urgent need for efficient remediation technology. The removal effect of bioavailable Zn and Cu by calcination and stabilization in contaminated soil was explored. And the influences of stabilizer types and dosage, temperature, and calcination time on the calcination and stabilization technology were investigated. The bone meal combined with CaO as a stabilizer achieved the highest efficiency for the calcination and stabilization of bioavailable Zn and Cu in contaminated soil by at 400 °C for 0.5-8 h, and the percentages were 99.46 % and 97.10 %, respectively. Moreover, the stabilization percentages of bioavailable Zn and Cu gradually increased with the stabilizer dosage increased from 0 % to 15 %. The calcination temperature at 100 °C had an excellent effect on the stabilization of bioavailable Zn and Cu, with the stabilization percentages reached about 100 % and 98.75 %, respectively. However, the calcination time (0.5-8 h) had very little effect on these pollutants. Given the remediation cycle's technological requirements and financial constraints, the optimal technical conditions were suggested that the calcination temperature was 100 °C, and reaction time was 1 h, the stabilization of bioavailable Zn and Cu can already reach 99.89 % and 98.89 %, respectively. This study demonstrates that the optimization of calcination and stabilization technology enables efficient and low - pollution remediation of heavy metal-contaminated soil, offering a new method for soil remediation with promising application prospects.