超细粉磨/活化剂协同作用下低品位磷矿粉活化机理研究

The rock phosphate in Hebei province is characterized by low phosphorus grade, high concentration ratio, and low phosphorus recovery. Taking coarse concentrate of phosphorus flotation from Baiquan iron mine as research object, collaborative technology of ultrafine grinding and activator is adopted to treat the low grade powdered rock phosphate. Based on the mineralogical characteristics analysis of the ore sample, the pure mineral systems including apatite are investigated by advanced analysis technics, such as electro-probe microanalyzer, atomic force microscopy, X-ray diffraction, Materials Studio, infrared spectrum, and X-ray photoelectron spectroscopy. Microscopic mechanism of phosphate mineral activation is studied through change rule analysis for crystallinity, amorphization, and lattice distortion of phosphate mineral as well as adsorption behavior, cleavage and formation of the chemical bonds, and elements content of phosphate surface. Coupling prediction model is established between the microscopic properties of phosphate mineral and available phosphorus content. The change rule analysis for size composition, specific surface area, particle morphology and statistics, surface tension, and surface energy of ultrafine phosphate powder was analyzed by laser particle size analyzer, BET surface area measurement, optical microscope, scanning electronic microscope, and surface tension apparatus. The regulation mechanism of phosphorus release is developed basing on the macroscopic prediction model for available phosphorus content in ultrafine phosphate powder. The treat process of low grade powdered rock phosphate by collaborative technology is optimization whilst the activation technique characterized by low power efficiency is formation.

本研究针对河北地区磷矿石中磷品位低、选比大、磷回收率低的问题，拟以柏泉铁矿的磷浮选粗精矿为研究对象，采用超细粉磨/活化剂协同技术处理该低品位磷矿粉。基于磷矿粉的工艺矿物学特性分析，以磷灰石纯矿物体系为试验原料，利用电子探针、原子力显微镜、XRD、Materials Studio、红外光谱、XPS等分析技术，研究超细纯矿物体系中磷矿物结晶度、无定形化、晶格畸变及磷矿物表面的吸附行为、化学键断裂和生成、元素含量等变化规律，建立磷矿物微观性质与有效磷含量间的耦合预测模型，探明磷矿物活化的微观作用机制；通过激光粒度分析仪、比表面积测定仪、光学显微镜、SEM、表面张力测定仪等测试手段，考察超细磷矿粉的粒度组成、比表面积、颗粒形貌及统计、表面张力和表面能等变化规律，建立磷矿粉中有效磷含量的宏观预测模型，形成磷矿粉释磷调控机制；开展超细粉磨/活化剂协同作用过程优化研究，形成低耗高效的磷矿粉活化工艺。

本项目基于河北磷矿资源品位低、分选过程磷元素流失较严重的问题，采用超细粉磨/活化剂协同活化低品位磷矿粉，可大幅提高产品中磷的枸溶率，使其可直接作为磷肥用，进而提高磷矿资源的利用率。.基于原料工艺矿物学性质，依次研究了磷灰石、磷灰石-石英、磷灰石-方解石、磷灰石-石英-方解石纯矿物体系超细粉磨过程中的性质变化，并考察了活化剂对磷灰石粉磨效果的影响。结果表明：超细粉磨可使磷灰石的中位径减小至2μm以下，表面自由能增加到10mN/m以上，细小颗粒发生吸附团聚现象；磷灰石结晶度降低、无定形化加剧，晶面间距和晶格参数增大，晶格体积随之增加；磷灰石表面元素含量无明显变化，PO43-的O-P-O振动峰向高频区漂移；磷灰石微观性质的变化提高了其释磷能力，枸溶率增加30个百分点以上。杂质矿物石英可强化磷灰石微观性质的变化，石英添加量为40%时，磷灰石枸溶率的增幅达到15个百分点；方解石的添加则不利于磷灰石的活化。磷灰石粉磨过程中添加活化剂，产品粒度无明显变化，表面性质和释磷能力变化较明显。建立了磷灰石枸溶率和表面自由能间的预测模型。.开展了超细粉磨/活化剂对低品位磷矿粉的活化研究，结果显示：超细粉磨同样可使磷矿粉的中位径降至2μm以下，比表面积增加至11m2/g以上，颗粒圆形度增加；矿物结晶度降低、表面自由能明显增加，磷矿粉的枸溶率大幅提高至70%以上。添加复合活化剂对产品粒度影响不大，但可提高其表面自由能，产品的枸溶率相应提高12.53~14.98个百分点。建立了磷矿粉枸溶率与比表面积和表面自由能间的预测模型。.开展了低品位磷矿粉粉磨方式和工艺参数优化研究，发现搅拌磨机较行星式球磨机更适合磷矿粉的超细粉磨，适宜的工艺参数为搅拌器转速550 r/min、磨矿浓度65%、充填率0.6、料球比0.5。活化剂可采用配比为1:1的膨润土和酒石酸，用量为磷矿粉质量的2%。