Brine System Effect An Activation-Migration-Enrichment Factors Of Copper Ion In Kuqa Basin

As an important media, brine in evaporate basin is vital carrier of metal ions, andof great significance for activation, migration, enrichment of metal ions during metalmineralization. However, there is no systematic and quantitative research on howchemical and physical properties of brine affect activation-migration-enrichmentmechanism of metal elements, and it is under much debate now. The thesis is toconduct a systematic study on leaching of surface brine in evaporate basin on copperin sandstone, to carry out the indoor simulation experiment through dynamic andstatic combination, and to mainly reveal activation, migration and enrichmentregularity of copper under condition of brines’ different salinities, temperatures, pHvalues, EH values.In the dynamic simulation experiment, it could be found that surface brine inhigh salinity, acid pH value=0.71or alkali pH value=10.28is most conducive toactivation and extraction of copper elements in surrounding rock. While staticsimulation experiment shows that activation ability of high salinity brines risessignificantly with the increase of temperature, especially at90℃; In CO2-rich, weakacid environment, high salinity of brines promotes activation of copper; But in H2S–rich, weak reduction environment, it surpress activation of copper.Based on the analysis of distribution of surface copper mineralization in Kuqabasin, copper mineralization genesis is classified as three genetic types: primarysedimentary origin, surface leaching origin,and hot brine origin.Their formationrespectively is related to dry salt lake brine, surface leaching brine, deep hot brine.Cupreous brine of different causes has a different way of migration. The surfaceleaching brine mainly flows from high to low in the earth’s surface, or downwardmigrates vertically in the vadose zone. The salt lake brine has no obvious migratingway. Deep hot brine often migrates from high pressure area to low pressure area alongfault belt.By means of the analysis of main control factors on copper mineralization of different genetic types in the study area, primary sedimentary origin is mainlycontrolled by paleoclimate and paleoenvironment. Hot brine origin is dominantlyaffected by fracture structure and sand body of good physical properties. The majorcontrol factors of surface leaching rigin are salt dome and favorable physical-property sand body in specific strata.Deep hot brine makes specific-horizon sandstone mineralization duringmigrating along fault zone, with larger metallogenic potential.Primary sedimentarytype may be further enriched,which is attributed to eluviation of secondary leachingbrine. Surface leaching brine mainly exerts subsequent transformation on neogenemaroon cupreous clastic rock at a great degree, and forms new mineralized points.Copper mineralization phenomena mainly occur in coarse sandstone in mioceneKangcun Formation. Therefore main faults and aassociated salt dome, and sand bodyof good physical property, the both may be important indicators for finding coppermineralization spot or underground copper mine.