This present study has assessed the resource recovery of tannery RO reject wastewater using crystallization in a double-jacketed agitated crystallization reactor under batch performance. The main objectives of this process were to remove sulphate from tannery RO reject wastewater and to recover the product as gypsum crystals. In the primary stage of initiator in crystallization, the CaCl2 initiator has better results in recovering the gypsum crystals involving chemical reactions. SEM, XRD, FTIR, and optical microscope characterize the product gypsum crystals. XRD results revealed that the uninformative size of gypsum crystals ranged between 54.61 and 61.86 nm, respectively. The experimental investigation on pH (4–12), temperature (30–180 °C), and reaction time (30–150 min) was performed. The maximum removal of sulphates from tannery RO reject wastewater was found to be 90–94 % under ideal pH 7, 30 °C for 30 min of reaction time, and 85–90 % gypsum crystal recovery, respectively. Moreover, gypsum cum Plaster of Paris was also investigated since interlocking structure and intercrystallite interactions can improve mechanical strength. It can be utilized for construction materials and ceramic mouldings for real-time applications. It could be concluded that the crystallization study helps in combating the harmful effects caused by occupying landfill sites and environmental damages.

中文翻译：

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双夹套搅拌结晶器石膏结晶去除回收反渗透制革废水中的硫酸盐


本研究评估了在间歇式双夹套搅拌结晶反应器中使用结晶对制革厂反渗透废弃废水进行资源回收的情况。该工艺的主要目标是去除制革厂反渗透废水中的硫酸盐，并以石膏晶体的形式回收产品。在结晶引发剂的初级阶段，CaCl2引发剂对于涉及化学反应的石膏晶体的回收效果较好。 SEM、XRD、FTIR 和光学显微镜表征了产品石膏晶体。 XRD 结果显示，石膏晶体的无信息尺寸范围分别为 54.61 和 61.86 nm。对 pH (4–12)、温度 (30–180 °C) 和反应时间 (30–150 分钟) 进行了实验研究。研究发现，在理想 pH 值 7、30°C 反应时间 30 分钟下，制革厂反渗透废水中硫酸盐的最大去除率为 90-94%，石膏晶体回收率分别为 85-90%。此外，还研究了石膏和熟石膏，因为联锁结构和晶间相互作用可以提高机械强度。它可用于实时应用的建筑材料和陶瓷成型品。可以得出结论，结晶研究有助于对抗占用垃圾填埋场和环境破坏造成的有害影响。