| 摘要: |
| 采用国内目前常用的两种密度三溴甲烷重液(重液1,密度为 2.87 g/cm3;重液2,密度为2.80 g/cm3),分别对黄河、长江、珠江等河流以及东海、南海等海区沉积物中的0.063～0.25 mm粒级进行了重矿物分离及对比实验。结果表明,重矿物分离过程中,两种重液的密度均发生了一定程度的变化,其中重液2的密度变化较大且呈整体增加趋势, 而重液1密度则较为稳定。比较而言,重液2分离出的重矿物质量分数较重液1的稳定,尤其处理白云石质量分数较高(如长江)的沉积物时,重液2较重液1分离 出的重矿物质量分数明显偏高。由于能有效区分方解石和白云石,重液2在分离东海、长江沉积物中的重矿物效果要好于重液1。为使分离出来的重矿物质量分数保 持稳定,每次提取完重矿物的剩余重液2需重新配平至密度为2.80 g/cm3。对两种重液分离出来的重矿物质量分数进行了回归分析,结果显示两者有一定的相关性,并可建立一元线性回归方程将两种结果进行粗略转换。由于在 重矿物分离过程中,损失的碎屑矿物很低(一般在个样总质量的1%以内),其对重矿物质量分数的影响可忽略不计。 |
| 关键词: 三溴甲烷 重矿物 对比分析 沉积物 河流 |
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| 基金项目:国家自然科学基金资助项目(40576032);中国科学院知识创新工程青年人才领域前沿项目(50602-13) |
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| Result comparison of heavy mineral separation with different specific densities of bromoform |
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| Abstract: |
| Bromoform with different specific gravities is used normally in separation of heavy minerals; they are heavy liquid 1 with specific density of 2.87 g/cm3 and heavy liquid 2 with specific density of 2.80 g/cm3. The sediments with grain sizes from 0.25 mm to 0.063 mm from three big rivers and seas are studied for comparison of separation results, which include the Huanghe(the Yellow River), the Changjiang(the Yangtze River), the Zhujiang(the Pearl River), the East China Sea and the South China Sea. The result shows that the specific densities of two heavy liquids change in the separation process. That is, specific density of heavy liquid 1 changes from 2.86 g/cm3 to 2.88 g/cm3, while that of heavy liquid 2 changes from 2.80 g/cm3 to 2.84 g/cm3. The contents of heavy minerals obtained using heavy liquid 2 were more stable than those of heavy minerals obtained using heavy liquid 1. When the content of dolomite is high in the sediments,such as those of the Changjiang River, heavy liquid 2 can separate higher content of heavy minerals than heavy liquid 1. In order to differentiate availably calcite and dolomite in the sediments especially in the East China Sea, the Changjiang River,heavy liquid 2 is advised to use in the process of separating heavy mineral. Considered obvious changes of specific density ,heavy liquid 2 needs to be re-configured before being used to separate heavy minerals. Separation results of heavy minerals with two kinds of heavy liquids are analyzed by the method of linear regression on the base of the linear regress equations constructed. Heavy mineral contents separated from the sediments with two kinds of heavy liquids have a close correlation and can be converted each other with the linear regression equations. During the process of heavy mineral separation the weight losses of detrital mineral samples are mostly less than 1%, whose influence on precision of heavy mineral separation from sediments can be ignored. |
| Key words: bromoform heavy mineral comparison analysis sediment rivers |
