含稀土磷灰石综合利用技术研究

Research of Technology for Comprehensive Utilization of a REEs-bearing Apatite

全球年产磷矿石约2.5亿吨,磷矿普遍含REO 0.1%~1%,稀土在磷矿中含量达10万吨,潜在经济价值巨大。含REO 2.60%、P_(2)O_(5)20.75%的某稀土磷灰石,主要的稀土矿物为独居石、直氟碳钙铈矿和氟碳铈矿等,矿物偏微细,主要分布于0.0001 mm~0.0800 mm粒级;稀土元素比较分散,53%分布于稀土矿物,25%分布于磷灰石中;主要的磷矿物为磷灰石,粒度偏粗,主要分布于0.01 mm~0.32 mm粒级,95%的磷赋存在磷灰石中。采用物理富集工艺富集含稀土磷灰石精矿,产率54.75%,含REO 2.60%、P_(2)O_(5)33.42%、Fe 4.34%,REO和P_(2)O_(5)回收率分别为56.04%和88.18%。硝酸分解磷精矿-氨水沉淀分离稀土与富磷浸出液;稀土沉淀采用硫酸酸化-水浸-复盐沉淀制备稀土复盐产品,稀土复盐含REO 40.18%,回收率85.73%;富磷浸出液采用稀土沉淀废液(富含Na_(2)SO_(4))沉淀除钙-液氨中和-蒸发造粒,制备N-P_(2)O_(5)化肥,磷肥含P_(2)O_(5)15.74%,回收率97.44%;研发的选-冶联合流程,REO和P_(2)O_(5)综合回收率分别为48.04%和85.92%,综合回收了磷和稀土。该技术可为同类型含稀土磷矿资源开发利用提供借鉴。

The global annual output of phosphate ore is about 250 million tons,which contains 100000 tons of rare earth with grade of 0.1%to 1%(REO)and has great potential economic value.A REEs-bearing apatite with REO 2.60%and P_(2)O_(5)20.75%contains rare earth minerals of monazite,synchysite and bastnaesite with fine grain size ranged from 0.0001 mm to 0.0800 mm.Rare earth elements are distributed dispersedly in the apatite with 53%in rare earth minerals and 25%in apatite.Apatite is the main phosphorus mineral with coarse grain size ranged from 0.01 mm to 0.32 mm.95%of the phosphorus is present in the apatite.Physical beneficiation was adopted to prepare REEs-apatite concentrate with yield 54.75%,REO grade 2.6%,P_(2)O_(3)grade 33.42%and Fe grade 4.34,and recovery for REO 56.04%and for P_(2)O_(5)88.18%.The concentrate was decomposed with nitric acid.Rare earth was separated from phosphorus-rich leachate with ammonia precipitation.Rare earth compound salt was prepared from rare earth precipitate through acidification with sulfuric acid-water leaching-composite salt precipitation.Rare earth composite salt contains 40.18%REO,with recovery of 85.73%.N-P_(2)O_(5)fertilizer was obtained from phosphorus-rich leachate through precipitation with rare earth precipitation waste liquid for calcium removal-ammonia neuralization-evaporation and granulation.The fertilizer contains 15.74%of P_(2)O_(5)with recovery of 97.44%.Comprehensive recovery of 48.04%for REO and 85.92%for P_(2)O_(5)was achieved with the process.The technology can provide reference for the development and utilization of the same type of REEs-bearing phosphate rock resources.