College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo, 454003, China.
School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430070, China.
J Environ Manage. 2022 Oct 15;320:115824. doi: 10.1016/j.jenvman.2022.115824. Epub 2022 Aug 3.
High-silica phosphogypsum (PG) is a kind of industrial by-product with great utilization potential. However, it is difficult to reuse PG directly due to the related gangue minerals (e.g., SiO), and thus efficient purification is required to allow its further applications. Herein, a typical high-silica phosphogypsum waste was purified by a new "reverse-direct flotation" method. The organic matters and fine slimes were removed by reverse flotation, and then, the silica impurity was removed by direct flotation. Via the closed-circuit flotation process, the whiteness of the PG concentrate is improved from 33.23 to 63.42, and the purity of gypsum in the PG concentrate increases from 83.90% to 96.70%, with a gypsum recovery of 85%. Additionally, the content of SiO is significantly reduced from 11.11% to 0.07%. In-depth investigations suggest that the difference in the floatability of gypsum and quartz is prominently intensified by flotation reagents at pH = 2-2.5, and thus leads to good desilication performance. Further characteristics of the PG concentrate prove that impurities have been well removed, and the PG concentrate meets the requirement of related standards for gypsum building materials. The flotation method reported here paves the way for the purification of high-silica phosphogypsum, which can be extended to the purification and value-added reutilization of other industrial solid wastes.
高硅磷石膏（PG）是一种具有巨大利用潜力的工业副产品。然而，由于相关的脉石矿物（如 SiO），PG 直接再利用比较困难，因此需要进行有效的净化处理，才能进一步应用。本文采用一种新的“反浮选-正浮选”工艺对典型高硅磷石膏进行了净化处理。反浮选脱除有机物和细泥，正浮选脱除硅杂质，闭路浮选可使磷石膏精矿白度从 33.23%提高到 63.42%，石膏纯度从 83.90%提高到 96.70%，石膏回收率 85%。同时，硅杂质含量从 11.11%显著降至 0.07%。深入研究表明，在 pH=2-2.5 时，浮选药剂明显增强了石膏和石英的可浮性差异，从而获得了良好的脱硅效果。磷石膏精矿的进一步特性表明，杂质已被有效去除，磷石膏精矿符合石膏建材相关标准的要求。本文所报道的浮选方法为高硅磷石膏的净化处理铺平了道路，该方法可扩展应用于其他工业固体废物的净化和增值再利用。
