Fe^(2+)-PO_(4)^(2-)混合溶液体系再生电池级FePO_(4)工艺研究

Study on the process of regenerating battery grade FePO_(4)in Fe^(2+)-PO_(4)^(2-) mixed solution system

为了缓解磷酸铁锂动力电池的大规模退役而造成严重的环境污染和资源浪费等问题,对其所含有价元素Fe、P、Li进行回收利用逐渐成为了研究热点,其中Fe、P的资源化尤为关键。以酸浸处理废旧磷酸铁锂电池正极材料所得净化液(Fe^(2+)-PO_(4)^(3-)混合体系)为原料,NH_(4)H_(2)PO_(4)为磷源,H_(2)O_(2)为氧化剂,开发了单滴法湿法合成电池级FePO_(4)工艺。研究结果表明:在最佳实验条件(温度90℃、体系浓度0.6 mol/L、pH=1.8、H_(2)O_(2)过量系数1.2、H_(2)O_(2)滴加速度10 mL/min、陈化时间2 h)下湿法合成FePO_(4)前驱体,Fe的回收率高,且该FePO_(4)前驱体烧制得到的磷酸铁锂正极材料容量高,初始放电比容量可达147.6 mAh/g。

In order to alleviate the serious environmental pollution and resource waste caused by the large-scale decommissioning of lithium iron phosphate power battery,the recycling of its valence elements Fe,P and Li has gradually become a research hotspot,among which the recycling of Fe and P is particularly critical.In this paper,a single drop wet synthesis process of battery grade FePO_(4) was developed with the purified solution(Fe^(2+)-PO_(4)^(3-)mixed system)obtained from acid leaching of waste lithium iron phosphate battery cathode material as raw material,NH_(4)H_(2)PO_(4) as phosphorus source and H_(2)O_(2) as oxidant.The results show that under the optimum experimental conditions(temperature 90℃,system concentration 0.6 mol/L,pH=1.8,H_(2)O_(2) excess coefficient 1.2,H_(2)O_(2) drop accelera-tion 10 mL/min and aging time 2 h),the recovery of Fe is high,the capacity of lithium iron phosphate cathode material obtained by firing FePO_(4) precursor is high,and the initial discharge capacity can reach to 147.6 mAh/g.