Study On The Numerical Simulation Of The Ore-forming Fluid System Of Nihe Iron Deposit In Lujiang, Anhui Province,China

The Ni-he iron deposit located in the northwest of Luzong volcanicbasin,in the Middle and Lower Yangtze River metallogenic belt, is a newdiscovered large scale deposit. At present the studies for the deposits is only inqualitative analysis and quantitatively calculated. This paper from the angle ofcompatible with existing research.Based on the research on the Ni-heIron.Deposit of predecessor by multi-disciplinary knowledge,such asGeochemistry、 Thermochemistry、 Fluid Mechanics and Ore-forming fluidmechanics.Calculate the component and physicochemical condition of theore-forming fluids of the superposed alteration zone.Calculate the dynamicsparameters and channel media parameters of theore-forming fluids.in theend.This paper chose the reliable geochemical software PHREEQC andmulti-physical coupling software COMSOL Multiphysics software,numericalsimulate the course of the Water-rock reaction occur between the ore-formingfluid and rocks，and the coupled ore-forming fluid migration flow field andtemperature field in detail by the PC, Get some new understanding:（1） During the process of numerical simulated the course of the Water-rockreaction occur on the ore-forming fluid in the superposed alterationin of theNi-he iron deposit,get the change of mineral saturation index in thereactionprocess,as the Mineral saturation index is greater than zero occur theformation of minerals,while be less than zero, occur the dissolution ofminerals. In the course of water-rock reaction,the saturation index of Quartzgradually Increased, but did not occur the precipitation,For carbonate minerals,produce the precipitation of theCalcite at the middle and final stages ofwater-rock reaction process,produce the precipitation of the Siderite with themigration of AnhydriteFor iron-bearing minerals, Fe³⁺turned into Fe2+at the early stage of theprocess,Fe²⁺turned into Fe3+at the middle and final stages of the process,getthe sequence of mineral deposits,in turn,Pyrite, Calcite, Siderite, Hematite,Gotthe changes of concentration of H+in the water-rock reaction would be3.662e-006.According to this,come to a conclusion that the pH of ore-forming fluidsdecreased at the early stage of reaciton,increased at the middle and final stages of reaciton in the superposed alterationin.（2） During the process of numerical simulated the ore-forming fluids int thetypical spaces of ore-bodies.Get the temperature field velocity field of theore-forming fluids in the simulated zone,set up the initial temperature of theore-forming fluids in the simulated zone to be460.0℃、350.0℃,the peak valueof temperature fluids is458.18～389.12℃、343.41～93.088℃,the velocity ofthe ore-forming fluids in the simulated zone focus on5.7224×10-5～3.0116×10-6m/s、1.2593×10-4～6.6281×10-6m/s,and the movement of theore-forming fluids shows cycle trend obviously in the simulated zone.