四川牦牛坪稀土矿韧性剪切带的发现及意义

四川牦牛坪稀土矿位于冕宁县城西南约22 km处的森荣乡和回龙乡境内,是世界上第三大稀土矿(裘愉卓等,2003)。由于冕西碱长花岗岩的侵吞,使区内地层非常零星,仅有泥盆系下部浅变质碎屑岩和碳酸盐岩、及第四系冲洪积,残坡积层。矿区内大面积分布的是酸性、碱性岩浆岩,按其特征、产状、成因及其与稀土矿产的成因联系和成岩时代,可分为燕山期碱长花岗岩系列和喜山期霓石英碱正长岩,另外

Progress in down-stream processing of biologically produced 1,3-propanediol

1,3-丙二醇是一种重要的化工原料,以甘油或葡萄糖为原料发酵法制备1,3-丙二醇具有原料可再生、反应条件温和等优点,是近年来国内外的研究热点。由微生物发酵获得的1,3-丙二醇发酵液是含多种强极性的醇及盐类的稀溶液,这使得采用传统的分离方法难以经济、有效地的将1,3-丙二醇从发酵液中纯化出来,后提取过程成为发酵法工业化生产1,3-丙二醇的瓶颈。1,3-丙二醇后提取过程主要包括微生物菌体等高分子物质的去除,盐的去除、回收,有机物的纯化和水的去除。以下对应用于以上分离过程的技术的研究进展进行讨论,提出在该领域应该重视的发展方向。1,3-propanediol is an important raw material in chemical industry.Microbial conversion of glycerol or glucose into 1,3-propanediol has been given much attention due to its renewable resource,mild reaction conditions,and other advantages.It is a challenge to efficiently separate 1,3-propanediol from a mixture of multiple components,such as 1,3-propanediol,2,3-butanediol,water,residual glycerol,ethanol,macromolecules and salts,for the reason that 1,3-propanediol,glycerol and 2,3-butanediol are all very hydrophilic and have intense polarity.The conventional evaporation and distillation techniques used in the purification of 1,3-propanediol suffer from the problem of high energy consumption and low recovery.It makes the recovery of 1,3-propanediol from a fermentation broth become a bottleneck in industrial production.The down-stream processing of biologically produced 1,3-propanediol mainly includes the removal of protein,salts,water and other impurities.This paper analyze the research progress of these separation technologies and point out the developing direction worth further investigation.国家高技术研究发展计划(863计划)(No.2008AA05Z302