Liaodong peninsula is located in the north of Sino-Korean paraplatform of which tectonics is relatively mature,an important part of Asian paraplatform.Due to the Yanshan movement,there developed lots of structures,such as folds and faults.The strata such as Cambrian is well exposed.Its main lithologies are limestone,quartzite,slate and sandstone.The Liaodong peninsula is located in the southern end of northeast China,surrounded by seas on three sides,and between the Yalu river and Liaohe river,mainly hilly and mountainous terrain.It belongs to the temperate continental monsoon climate,mean annual temperature is around 10 ℃,and mean annual rainfall is 550-950 mm.Rainfall is mainly concentrated in July and August.In this paper,the design of pretreatment methods is as follows.First of all,the samples are digested with 30％ H2O2 to remove organic matter,and then four methods are used for preprocessing.Of them,the method A is not disposed by hydrochloric acid,methods B,C and D are all decomposed by hydrochloric acid solution to remove the residual carbonate and secondary free oxides in order to eliminate the cementation of debris and mineral particles.HCl of method C is in the boiling conditions of the reaction.HCl of method B is under normal temperature conditions,and method D changes the ultrasonic vibration time.There are different pretreatment methods for the samples to test,the purpose of which is to analyze the influence of various methods on particle size measurement.Combined with the laser diffraction particle size analyzer,it can explore the analysis results of particle size and the reason for the difference to recommend the most optimal pretreatment method,which can facilitate further studying on weathering crust in the region of grain-size analysis.The experimental results show that the pretreatment methods have a certain effect on the particle size measurement results of red weathering crust in northern China,and the different pretreatment methods make the grain size of the samples have about 5 ％ rotates.Considering the stability of the experiment,the error of the parallel tests of the 4 methods reaches up to 6.78％.Under the existing recognized conditions,reproducibility of particle size measurement results is the most basic demand to experiments.In this paper method C is better than others (A,B and D).The results in different pretreatment methods reflect the basic characteristics of the weathering crust in particle size distribution.The method mentioned in the paper is suitable for the weathering crust of north China,the other types and regions should be combined with the actual situations in order to obtain a more ideal test result.%选取中国北方岩溶区红色风化壳为研究对象,首先用浓度为30％的H2O2去除样品中的有机质,然后用4种不同的前处理方法分别进行处理,其中方法A未用盐酸溶液处理,方法B、C、D均用盐酸溶液分解可能存在的残余碳酸盐和次生游离氧化物,以消除其对机械颗粒可能存在的胶结作用,此外方法C的HCl在煮沸的条件下反应,方法B的HCl在常温条件下进行,方法D则更改了超声波振荡的时间.本文样品采用Beckman公司生产的LS13320型激光衍射粒度测试仪进行测量.结果表明,样品前处理方法对中国北方红色风化壳粒度分析结果有影响,不同的前处理方法使样品的粒度值最大产生5％左右的变化;从实验的稳定性上考虑,4种方法的平行试验标准偏差最大达到6.78％.在现有的认识条件下,粒度测量结果的可重复性是最基本的要求.本文认为方法C的测量效果要好于其他方法.
展开▼
