【作者】 陈文祥；

【导师】 严春杰；

【作者基本信息】 中国地质大学 ， 材料科学与工程， 2022， 博士

【摘要】 织金磷矿普遍伴生稀土元素,是目前国内磷矿伴生稀土资源量规模最大的区域。截止2014年,织金磷矿已累计查明磷块岩伴生稀土氧化物（RE₂O₃）资源量350.18万吨,RE₂O₃品位平均0.1036%。稀土配分接近价值最高的中钇富铕离子型稀土矿,是继离子型稀土矿之后重要的中重稀土后备资源。织金含稀土磷矿中稀土含量低,胶磷矿的结晶程度差,稀土元素的赋存状态一直缺乏直接有力的证据和科学明确的结论,严重制约了稀土选矿富集与提取分离技术研究。织金磷矿中稀土元素的赋存状态及其提取分离研究对含稀土磷矿的开发利用具有十分重要的科学与现实意义。论文以织金含稀土磷矿作为研究对象,系统采集代表性的试验样品,对其工艺矿物学和稀土元素赋存状态进行深入研究,在此基础上,开展详细的物理选矿、化学选矿、稀土提取分离研究,并对稀土元素赋存状态与含稀土磷矿的形成机理、稀土化学选矿机理以及稀土浸出液旋蒸机理进行了深入分析,得出如下主要结论:（1）织金打麻厂含稀土磷矿石中的主要矿石矿物为胶磷矿,主要伴生有益组分为稀土和氟,主要脉石矿物为白云石、水黑云母、石英、玉髓、黄铁矿等。矿石矿物和脉石矿物嵌布粒度细,胶磷矿解离性差。磷和稀土都主要赋存在胶磷矿中,物理选矿不能单独分选稀土,稀土只能随磷一起富集。从原矿中分选胶磷矿,稀土最高品位RE₂O₃0.21%,理论回收率87.15%,磷的最高品位P₂O₅35.85%,理论回收率90.18%。（2）织金打麻厂含稀土磷矿中,稀土元素主要以磷酸盐超显微包体的形式赋存在胶磷矿、白云石以及石英、玉髓、长石、黄铁矿等矿物中,占稀土总量的91.73%,6.80%的稀土元素以类质同象形式赋存在磷灰石、结晶态胶磷矿和磷铝锶石等矿物中,1.36%的稀土元素以吸附状态的形式赋存在水黑云母等粘土矿物中,仅0.10%的稀土元素以独立矿物形式赋存在独居石、磷铝铈矿等矿物中,与有机质结合形式存在的稀土元素含量甚微。稀土元素的赋存状态形成机制主要受稀土磷酸盐的溶度积和微环境控制。胶磷矿的形成机理为“稀土磷酸盐超显微包体成核-钙磷酸盐化学共沉淀”模式。（3）采用一粗三扫反浮选流程选别织金打麻厂含稀土磷矿,获得了产率52.55%,P₂O₅品位28.67%,回收率85.72%,RE₂O₃含量0.22%,回收率82.58%,Mg O含量0.89%,脱除率92.56%的浮选精矿产品。原矿P₂O₅品位17.58%,RE₂O₃含量0.14%,Mg O含量6.69%,Si O₂含量10.42%。选矿比2.93,选别指标良好。（4）采用3次循环浸出化学选矿工艺富集织金摩天冲含稀土磷矿浮选精矿中稀土,RE₂O₃含量从0.13%提高到0.92%,富集了7.03倍,回收率达91.90%,P₂O₅含量从31.89%降低至1.87%,浸出率高达99.23%,实现磷与稀土的高效分选。化学选矿的机理为,基于稀土元素主要以磷酸盐超显微包体的形式存在,以及稀土磷酸盐的溶解度远远低于钙磷酸盐,通过调控化学溶解平衡条件,选择性浸出磷,使稀土保留在渣中,从而实现磷与稀土的化学分选。（5）采用盐酸常压加温浸出工艺从稀土化学精矿中提取稀土,在中试规模水平上,获得了RE₂O₃浸出率为96.44%,P₂O₅浸出率为97.42%,F浸出率为88.83%的良好指标,效果优于实验室试验结果。最佳工艺条件为:盐酸用量为理论用量的105%,盐酸浓度为25%,浸出温度为70℃,浸时间为常温浸出30分钟,加温浸出180分钟。（6）采用稀土浸出溶液旋转蒸发降酸除氟脱硅-离子交换树脂吸附分离-草酸沉淀稀土-焙烧制备稀土氧化物工艺,获得RE₂O₃含量为56.69%的稀土氧化物产品,产品中Ca O含量为42.54%,Al₂O₃含量为0.46%,Fe₂O₃含量为0.31%。旋蒸降酸除氟脱硅的机理是,利用盐酸的挥发性和氟硅酸在强酸中的不稳定性,在减压加热条件下,通过气液平衡和化学平衡移动,促进盐酸和四氟化硅气体一道逸出稀土浸出液体系进入气相,从而达到降低溶液酸度以及除氟脱硅的目的。（7）含稀土磷矿稀土选冶的最佳工艺技术路线为:物理选矿降镁-化学选矿脱磷-盐酸加温浸出稀土-减压加温旋转蒸发降酸除氟脱硅-离子交换分离除杂-草酸沉淀分离铁铝-焙烧制备稀土氧化物。按此技术路线,获得织金摩天冲含稀土磷矿的稀土选冶总回收率达75.67%,显著优于磷酸法55.60%的成果指标。生产成本为15.17万元/吨RE₂O₃产品,显著低于硫酸法40万元/吨RE₂O₃产品的生产成本。更多还原

【Abstract】 Zhijin phosphate rock is generally associated with rare earth elements,which is the largest area in China at present.As of 2014,Zhijin phosphate mine has identified3.518 million tons of rare earth oxide（RE₂O₃）resources associated with phosphate rock,with an average RE₂O₃grade of 0.1036%.The middle yttrium and europium rich ionic rare earth ore with the highest rare earth distribution value is an important medium and heavy rare earth reserve resource after the ionic rare earth ore.The content of rare earth in Zhijin rare earth containing phosphate rock is low,the crystallization degree of collophanite is poor,and the occurrence state of rare earth elements has been lack of direct and powerful evidence and scientific and clear conclusions,which seriously restricts the research on rare earth beneficiation enrichment and extraction and separation technology.The study on the occurrence of rare earth elements in Zhijin phosphate rock and their extraction and separation has very important scientific and practical significance for the development and utilization of rare earth containing phosphate rock.The paper takes Zhijin rare earth containing phosphate rock as the research object,systematically collects representative test samples,and conducts in-depth research on its process mineralogy and occurrence state of rare earth elements.On this basis,it carries out detailed research on physical beneficiation,chemical beneficiation and rare earth extraction and separation,and deeply analyzes the occurrence state of rare earth elements and the formation mechanism of rare earth containing phosphate rock,the mechanism of rare earth chemical beneficiation and the mechanism of rare earth leaching solution distillation,The main conclusions are as follows:（1）The main ore mineral in the rare earth phosphorus ore of Zhijin Dama plant is collophanite,the main associated beneficial components are rare earth and fluorine,and the main gangue minerals are dolomite,hydrobiotite,quartz,chalcedony,pyrite,etc.Ore minerals and gangue minerals have fine particle size and poor dissociation of collophanite.Phosphorus and rare earth are mainly contained in collophanite.Physical beneficiation cannot separate rare earth,and rare earth can only be enriched with phosphorus.The collophanite is separated from the raw ore.The highest grade of rare earth RE₂O₃is 0.21%,and the theoretical recovery is 87.15%.The highest grade of phosphorus P₂O₅is 35.85%,and the theoretical recovery is 90.18%.（2）In the rare earth containing phosphate rock of Zhijin damachang,the rare earth elements are mainly contained in collophanite,dolomite,quartz,chalcedony,feldspar,pyrite and other minerals in the form of phosphate ultramicro inclusions,accounting for 91.73%of the total rare earth elements,and 6.80%of the rare earth elements are contained in apatite,crystalline collophanite,phosphoalumino strontium and other minerals in the form of isomorphism,1.36%of rare earth elements are stored in clay minerals such as hydrobiotite in the form of adsorption,only 0.10%of rare earth elements are stored in monazite,bauxite and Cerite in the form of independent minerals,and the content of rare earth elements in the form of combination with organic matter is very small.The occurrence and formation mechanism of rare earth elements are mainly controlled by the solubility product and microenvironment of rare earth phosphate.The formation mechanism of collophanite is a"rare earth phosphate ultramicro inclusion nucleation calcium phosphate chemical coprecipitation"model.（3）The one roughing and three scavenging reverse flotation process was used to separate rare earth phosphate ore from Zhijin Dama plant.The flotation concentrate product with a yield of 52.55%,P₂O₅grade of 28.67%,recovery of 85.72%,RE₂O₃content of 0.22%,recovery of 82.58%,Mg O content of 0.89%and removal rate of92.56%was obtained.The grade of raw ore P₂O₅is 17.58%,the content of RE₂O₃is0.14%,the content of Mg O is 6.69%,and the content of Si O₂is 10.42%.The beneficiation ratio is 2.93,and the beneficiation index is good.（4）The three cycle leaching chemical beneficiation process is used to enrich the rare earth in the flotation concentrate of Zhijin motianchong rare earth containing phosphate ore.The content of RE₂O₃is increased from 0.13%to 0.92%,enriched by7.03 times,the recovery rate is 91.90%,the content of P₂O₅is reduced from 31.89%to1.87%,and the leaching rate is as high as 99.23%,realizing the efficient separation of phosphorus and rare earth.The mechanism of chemical beneficiation is that based on the fact that rare earth elements mainly exist in the form of phosphate ultramicro inclusions and that the solubility of rare earth phosphate is far lower than that of calcium phosphate,the chemical separation of phosphorus and rare earth can be realized by adjusting the chemical dissolution equilibrium conditions and selectively leaching phosphorus to keep rare earth in the slag.（5）Rare earth is extracted from rare earth chemical concentrate by hydrochloric acid atmospheric pressure heating leaching process.At the pilot scale level,good indexes of RE₂O₃leaching rate of 96.44%,P₂O₅leaching rate of 97.42%and f leaching rate of 88.83%are obtained,and the effect is better than the laboratory test results.The optimum technological conditions are as follows:the dosage of hydrochloric acid is105%of the theoretical dosage,the concentration of hydrochloric acid is 25%,the leaching temperature is 70℃,the leaching time is 30 minutes at room temperature and 180 minutes at elevated temperature.（6）A rare earth oxide product with a content of 56.69%of RE₂O₃was obtained by the process of rotary evaporation of rare earth leaching solution,acid removal,fluorine removal and desilication,ion exchange resin adsorption and separation,oxalic acid precipitation and roasting.The content of Ca O,Al₂O₃and Fe₂O₃in the product was42.54%,0.46%and 0.31%respectively.The mechanism of removing fluorine and desilication by rotary evaporation is to make use of the volatility of hydrochloric acid and the instability of fluorosilicic acid in strong acid to promote hydrochloric acid and silicon tetrafluoride gas to escape from the rare earth leaching liquid system and enter the gas phase through the movement of gas-liquid equilibrium and chemical equilibrium under the condition of reduced pressure heating,so as to achieve the purpose of reducing the acidity of the solution and removing fluorine and desilication.（7）The best technological route for rare earth beneficiation and smelting of rare earth containing phosphate ore is as follows:physical beneficiation magnesium reduction chemical beneficiation dephosphorization hydrochloric acid heating Leaching Rare Earth decompression heating rotary evaporation acid removal fluorine and desilication ion exchange separation impurity removal oxalic acid precipitation separation iron and aluminum roasting to prepare rare earth oxide.According to this technical route,the total recovery rate of rare earth beneficiation and smelting of Zhijin motianchong rare earth containing phosphate rock is 75.67%,which is significantly better than the achievement index of 55.60%of phosphoric acid method.The production cost is 151700yuan/ton of RE₂O₃products,significantly lower than the production cost of 400000 yuan/ton of RE₂O₃products by sulfuric acid method.更多还原