深海多金属结核物理特性及其对采输过程的影响概述

Overview of Physical Characteristics of Deep-sea Polymetallic Nodules and the Effects on Mining and Transportation Processes

文章旨在确定深海多金属结核的物理特性,并分析其对采输过程的影响,以指导工程应用。总结了深海多金属结核开采的最新研究进展,通过对数据进行统计整理、回归分析,确定了结核形成机理及主要成分、在海底的分布特性、结核形态及构造、结核尺寸与重量关系、含水量、密度、孔隙特性及结核强度等关键物理特性。研究表明:结核形状多样,质松多孔隙,含水率高,近似均匀分布在海床上或浅泥层中。颗粒质量和尺寸联合概率分布具有长右尾特性,需使用更广义的联合概率密度函数copula才能准确建模。结核抗拉强度随结核直径增大按对数函数递减。此外,深海高压环境下结核的开采需更多能耗,且结核表现出更高的延性。结合固液两相流分析和颗粒沉降理论,分析了结核形状、尺寸、密度等主要参数对水力举升过程的影响,确定了颗粒破碎的主要方式和规律,总结了不同粒径级配输运造成堵塞的可能原因。

This study aimed at determining the physical characteristics of deep-sea polymetallic nodules and analyzing their influence on the mining and transportation process,so as to guide engineering applications.This work summarized the latest progress of deep-sea mining of polymetallic nodules,through the statistics and regression analysis of available data,the formation mechanism of polymetallic nodules and the main composition,the distribution characteristics on the sea floor,the morphology and structure,the relationship between size and weight,water content,density,pore characteristics,the strength and other key physical properties were determined.The study indicated that the polymetallic nodules were of various shapes,and it was loose and porous,the water content was high,and they were approximately uniformly distributed on the seabed or in shallow mud.The joint probability distribution of particle mass and size had a long right tail,more generalized joint probability density function of copula should be used in accurately modeling.Besides,the tensile strength of nodule decreased logarithmically with the increase of nodule diameter.In addition,the mining of nodules in deep-sea high-pressure environment required more energy consumption,and the nodules exhibited higher ductility.Combined with the theory of solid-liquid two-phase flow analysis and particle settlement theory,the influence of main parameters such as shape,size and density of nodules on the hydraulic lifting process was analyzed,the main way and law of particle fragmentation were determined,and the possible causes of blockage caused by transportation with different particle sizes were summarized.