| Fine mineral processing helps to solve the problems of both low concentrate grade and low recovery in the production,but also leads to tailings refinement.With the increase of degree of tailings refinement,fine tailings damming problems is increasingly outstanding.Fine grained tailing is one special kind of soft clay with poor permeability,long consolidation time and low mechanical strength.This properties is bad for sediment characteristic,reservoir settlement distortion characteristics and dam structure strength.So it is a significant value for both academic and concrete project to study the effect of tailings refinement on physico-mechanical properties and its internal mechanism.Through on-site investigation,laboratory test,theoretical analysis and numerical calculation,this paper presents an investigation into the macro-characteristics of fine grained tailings and its micro-mechanism.The main contents and conclusions in this paper are as follow as:1.This paper presents an investigation into the microscopic structure of the tailings particles through grain size analysis test,XRD,optical microscopy,electron microscopy and digital image processing.In this paper,the mineral composition characteristics of sand particles,silt particles and clay particles is discussed,geometry characteristics of tailings particles is analyzed from the perspective of outline,angularity and surface topography.The specific characteristic of sticky fine particles is delved.Particle size distribution function model and crushing process model are also established.2.This paper presents an investigation into the sedimentary layering law and time evolution law through surface sedimentary tailings analysis and settling column experiments.In this paper,the effect of distance on particle characteristic is discussed.The relationship between particle size and deposition distance is established.Microstructure of tailings sediment and layering basis is studied.The relationship between morphology and time is analyzed,and electric double layer theory is used to explain the influence of flocculation on sedimentary characteristics.3.In order to study the effect of particle composition on compression consolidation characteristics of viscous tailings,this paper does an experiment on the remolded sand tailings,silty tailings and viscous tailings.Then analyzing the differences of different fine tailings on the compression consolidation characteristics,describing the secondary consolidation of viscous tailings,discussing the relationship between secondary consolidation coefficient,consolidation pressure,time.Finally,we establish the one-dimensional model of consolidation empirical and element,which is suitable for fine tailings material.4.In order to study the effect of fine content on tailings strength and deformation characteristics,this paper adopts consolidated undrained three axial test and mesoscopic discrete element simulation test.through these experiments,we study the macro-and micro-correlation of the effect of fines content on tailings strength and its internal mechanism.Then discussing the law of tailing soil and discriminant basis of critical particle content.Finally,we propose a chain weakening hypothesis to explain the effect of fine particle in tailings.5.Through the case analysis of dam construction,this paper compared the composition and structure of coarse tailings dam and fine tailings dam.The effect factors of dam stability are analyzed.The effect of radiation well on the stability of dam body is studied.Influence scope to the mining area predicted.Finally we put forward technical measures to solve the related problems. |
PDF Full Text Request