Solid Potash Mineral Characteristics And Genesis Mechanism Studies In The Bieletan Section Of Charhan Salt Lake

The Bieletan section is located in Qarhan Salt Lake western, which Qhs3saltlayer has180million tons of low-grade solid potassium. Types and distribution oflow-grade grade solid potash impact on the potash dissolved mining efficiency,therefore to carry out this study has important practical significance. Based on theseven drill core catalog, mineral identification and testing of core geochemicalanalysis, the paper research potassium-rich layer in Qhs3salt layer, symbioticassociation characteristics and distribution of minerals, material sources of salt andpolyhalite formation mechanism.Studies shows that solid potassium mineral is low-grade solid mineral ore inQhs3salt layer of The Bieletan section, which potash minerals disseminated mostlydispersed growth between halite crystals, and some appear lens-shaped which poorore continuity. The Bieletan section appear four potassium-rich layers in western andfive potassium-rich layers in eastern and central. Content of potassium reach theminimum cut-off grade of KCl in depth for3.10~3.60m and5.80~10.20m inwestern,11.25~12.20m in central,4.15~4.65m and4.95~5.50m depth in eastern.only in the eastern part of the8.25~8.75m and10.35~10.85m reached KClindustrial grade (6%) contents, which are10.91%and11.42%, other layerspotassium-rich levels were below the minimum cut-off grade of KCl (3%).However the average content (KCl) of potassium are2.25%,1.49%,1.95%from westto east, lower than the minimum cut-off grade. Do not indicate solid potassium oregrade is low, poor continuity features Le floodplain segments. This indicates that solidpotash ore grade is low and poor continuity features in the Bieletan section.Using three saline minera methods (thin section analysis, XRD and SEM)identify three major potash minerals: sylvite, carnallite and polyhalite. Sylviteintergrowth with halite, and Sylvite intergrowth with carnallite in blatt of halite;Carnallite widely distributed, but its content is generally low, and more occasionallyoccur between in rock salt crystals or cave of halite. Carnallite more form euhedral-hypidiomorphic crystal, some appeared metasomatic reaction with polyhalite; polyhalite more output between halite crystals, the polyhalite appear primary orignand penecontemporaneous replacement genesis two kinds of yielding, and the latterdominated. The primary orign polyhalite mineral forms radial fibers or pompon, and asmall amount of granular shape; The penecontemporaneous replacement genesispolyhalite mostly forms by replacement with gypsum, hemihydrate gypsum, anhydriteand carnallite, which intergrowths with detrital mineral, and appear to have a smallamount of replacement with halite. Comprehensive mineral identify results shownthat the build order is haliteâ†'sulfate minerals (gypsum, hemihydrate gypsum,anhydrite)â†'sylvite, carnalliteâ†'polyhalite. From west to east, the distribution ofthree potash mineral appear to gradual change from polyhalite dominated to sylvite–carnallite dominated.Geochemical studies show the average value of potassium ions have little changein the Bieletan section, mostly around1%, the lower value of some resions is affectedlow dissolved mineral tests. Calcium content in both western and central is greaterthan2%, while in the east are less than1.8%, decreasing from west to east, and sulfateions appear the same law which reduce from the8.23%of west to4.02%of the east.Sodium, magnesium and chloride ions do not change significantly, magnesium ionappeared vertical differentiation in the vertical, with the depth increases graduallyincreased. Content of Trace element lithium and strontium gradually increases fromeast to west, and lithium element gradually increased from shallow to deep lithiumelement, which is mostly due to most of the lithium element story in the detritalminerals which mostly distribute in the lower part. The content of strontium far lowerthan potassium layers of marine evaporite, which is the same opinion thatnonmarine causes of the Charhan Salt Lake. The depth for2~3m in the Bieletansection, strontium values appear a extremely high value, while found the high value ofpotassium ions, and this shows that there has been a big strong concentratedevaporation event in this depth, resulting in evolve of strontium and potassium.Cluster analysis revealed that the mixed a deep material recharge with surface waterand contribution of volcanoes, geothermal activity on salt accumulation.Combined with supply conditions of crystal brine, the study found that the distribution of polyhalite related to the supply direction of the crystal brine.Magnesium sulfate subtype brine of Senie lake supply crystal brine from west to east,while porosity and specific yield are larger in Qhs3layer of the study area,and thisprovide a channel and places for brine of Senie lake and pre-formed saline minerals(sulfate minerals, carnallite and halite) occur metasomatic reaction, which is lake andexplain the occurrence of reaction provides a channel and places. Polyhalite is alongthe supply direction of the crystal brine (from west to east) to replace of a sulfateminerals, carnallite or even occur the phenomenon of replacement withhalite.Comprehensive analysis believe that the formation of polyhalite of the Bieletansection is the result of replacement brine of Senie lake with the early formed salineminerals.