利用铁矾渣制备轻质固硫陶粒

铁矾渣是锂电回收过程黄铁矾法除铁产生的废渣，高温条件下易分解产生二氧化硫。通过在铁矾渣中添加固硫剂制备固硫陶粒是实现铁矾渣合理利用的有效途径。通过计算高温环境下不同氧化物吉布斯自由能，并结合固硫剂铁矾渣混合焙烧实验，确定固硫效果较优的氧化钙作为固硫陶粒的固硫剂；同时，考察固硫剂掺量对固硫陶粒的固硫效果及性能的影响。结果表明，随着固硫剂掺量增加固硫率上升，固硫陶粒的吸水率和抗压强度先增加后减少，堆积密度和表观密度先减少后增加。当Ca/S 比为 2.35时，固硫陶粒的固硫率达到最高48.8%，吸水率为3.89%，抗压强度为0.79 MPa，表观密度和堆积密度分别为0.72 g·cm^-3和0.51 g·cm^-3。通过XRD和TG-DSC-FTIR分析固硫机理，发现硫酸盐通过与固硫剂相互作用形成了分解温度更高的CaSO₄和K₂SO₄。固硫陶粒的毒性浸出实验结果符合国家标准。本研究结果可为铁矾渣的高值环保利用的相关研究提供参考。

Preparation of Light Sulfur Retention Ceramsite from Jarosite Residues

Jarosite residues is the waste residue produced by iron removal in jarosite method in the process of lithium-ion batteries recovery, and it decomposes to sulfur dioxide easily at high temperatures. The rational and effective way to utilize jarosite residues is to prepare sulfur retention ceramsite by adding sulfur retention agent. Through the thermodynamic calculation of different oxides, and combined with mixed calcination experiment of sulfur retention agent with jarosite residues, CaO was chosen as the sulfur retention agent in the paper. The effect of the amount of sulfur retention agent on sulfur retention efficiency and properties of ceramsite were investigated. Results showed that the increase of the amount of sulfur retention agent led to an increase in sulfur retention efficiency, an increase and then decrease trend in water absorption rate and compressive strength, and the reverse trend in bulk density and apparent density. Under Ca/S of 2.35, the sulfur retention rate could reach to the highest of 48.8%, with the water absorption rate of 3.89%, the compressive strength of 0.79 MPa, and the apparent and bulk densities of 0.72 g·cm−3 and 0.51 g·cm−3, respectively. XRD and TG-DSC-FTIR were used to further investigate the mechanism of sulfur retention. It was found that CaSO4 and K2SO4 with higher decomposition temperature were formed by the interaction of sulfate with sulfur retention agent. The result of toxicity leaching meet the national standard. This study provided a reference for further research on the high-value and environmental protection applications of jarosite residues.