Synthesizing slow-release fertilizers via mechanochemical processing for potentially recycling the waste ferrous sulfate from titanium dioxide production.
The goal of this study is aimed to develop a novel process to recycle the ferrous sulfate, the by-product of titanium dioxide industry. Zinc sulfate was added in the process of milling ferrous sulfate with calcium carbonate (CaCO3). The sulfates were transformed into carbonates to serve as slow-release fertilizers by co-grinding the starting materials of FeSO4·7H2O, ZnSO4·7H2O, and CaCO3with small amounts of water in a planetary ball mill. The prepared samples were characterized by X-ray diffraction (XRD) analysis and quantitative measurements of the soluble ratios in water and 2% citric acid solution. It was found that Fe and Zn ions as sulfates were successfully combined with CaCO3to form the corresponding Fe and Zn carbonates respectively. After milling, the release ratios of Fe and Zn nutrients in distilled water could be controlled at 0.1% and 0.7% respectively. Meanwhile, the release ratios of them in 2% citric acid solution were almost 98% and 100%. Milling speed was the critical parameter to facilitate the transformation reaction. The proposed process, as an easy and economical route, exhibits evident advantages, namely allowing the use of widely available and low-cost CaCO3as well as industrial wastes of heavy metal sulfates as starting samples to prepare applicable products.
School of Resources & Environmental Engineering, Wuhan University of Technology, 430070 Wuhan, China.
Xuewei
X
Li
School of Resources & Environmental Engineering, Wuhan University of Technology, 430070 Wuhan, China.
Zhiwu
Z
Lei
School of Resources & Environmental Engineering, Wuhan University of Technology, 430070 Wuhan, China.
Jun
J
Qu
School of Resources & Environmental Engineering, Wuhan University of Technology, 430070 Wuhan, China.
Zhao
Z
Li
School of Resources & Environmental Engineering, Wuhan University of Technology, 430070 Wuhan, China.
Xiaowen
X
Zhou
School of Resources & Environmental Engineering, Wuhan University of Technology, 430070 Wuhan, China. Electronic address: zhangqw@whut.edu.cn.
Qiwu
Q
Zhang
D002119:Calcium Carbonate / Q000737:chemistry; D002254:Carbonates / Q000737:chemistry; D005296:Ferrous Compounds / Q000737:chemistry*; D005308:Fertilizers; D007220:Industrial Waste; D019216:Metals, Heavy / Q000737:chemistry; D059027:Recycling; D013431:Sulfates / Q000032:analysis / Q000737:chemistry; D014025:Titanium; D014961:X-Ray Diffraction; D017967:Zinc Compounds / Q000737:chemistry
D002254:Carbonates; D005296:Ferrous Compounds; D005308:Fertilizers; D007220:Industrial Waste; D019216:Metals, Heavy; D013431:Sulfates; D017967:Zinc Compounds; C009495:titanium dioxide; C020748:ferrous sulfate; D014025:Titanium; C036650:zinc carbonate; D002119:Calcium Carbonate
CaCO(3); Ferrous sulfate; Mechanochemical; Slow release fertilizer; Zinc sulfate