Surface pretreatment can change the surface properties of minerals,placing them in either a favorable or an unfavorable state for flotation.To solve the separation problem associated with magnesite and dolomite,surfac...Surface pretreatment can change the surface properties of minerals,placing them in either a favorable or an unfavorable state for flotation.To solve the separation problem associated with magnesite and dolomite,surface pretreatment experiments with citric acid,tartaric acid,and tannic acid(TA)on magnesite and dolomite as well as flotation experiments on pretreated samples were performed in this study.Experimental results demonstrated that when citric acid and tartaric acid are used for surface pretreatment,the separation effect of magnesite and dolomite is poor.However,when TA is used,the separation effect of magnesite and dolomite improves.SEM and BET analysis indicated that surface pretreatment with TA changes the surface morphology of the two minerals,resulting in additional concave pores on the dolomite surface,and a significant increase in pore size and specific surface area.The adsorption quantity test and contact angle measurement demonstrated that after surface pretreatment with TA,the magnesite adsorption capacity on sodium oleate(NaOL)slightly decreases and the dolomite adsorption capacity on NaOL considerably decreases.XPS detection concluded that the surface pretreatment of TA on the magnesite surface mainly relies on physical adsorption with weak adsorption ability and poor ability to act on Mg sites.The TA surface pretreatment action on the dolomite surface is mainly through chemical adsorption,and it is strongly and selectively adsorbed on the Ca site of dolomite through O.Actual ore rough selection experiments reveal that TA pretreatment successfully removes dolomite from magnesite,resulting in a high-quality magnesite concentrate characterized by a MgO grade of 45.49%and a CaO grade of 0.75%.展开更多
This paper summarizes recent data about magnesite and talc genesis in Carboniferous host rocks of Western Carpathians (Slovakia) , which occur in two distinct belts in tectonic superunit Veporicum and its contact zone...This paper summarizes recent data about magnesite and talc genesis in Carboniferous host rocks of Western Carpathians (Slovakia) , which occur in two distinct belts in tectonic superunit Veporicum and its contact zone with Gemericum. The northern Sinec magnesite and talc belt (with main deposits Kokava, Sinec, Samo, Hnust'a-Mutnik) contains economic accummulation of magnesite and talc, while in the southern Ochtina belt ( main deposits in Dubrava massif-Dubrava, Mikova, Jedl'ovec; Lubenik, Ochtina, Kosice-Bankov, Banisko, Medvedia) the magnesite is dominating.The magnesite genesis by successive replacement of Carboniferous calcite to dolomite and magnesite during metamorphic process Ml (northern belt 280-400℃; , southern belt 370-420℃: ; Radvanec & Prochaska, 2001; Kodera & Radvanec, 2002) , being supplied by Mg from Permoscythian evaporitic bittern brines, relates to Variscan post-collisional (post-VD) evolution. The extensional tectonics and the high heat flow facilitated the generation of a hydrothermal system.The time-separated later metamorphic and sourcely different fluid flow event (M2; 1. c. ) produced talc. Tectonic, microtectonic, metamorphic and geochronological data relate the talc origin with the Alpine Upper Cretaceous (88-84 Ma; Maluski in Kovacik et al. , 1996) tectonothermal event AD2. This event, being the consequence of Alpine collisional ( AD1 ) crustal thickening and metamorphic core complex origin, meant regional extension and pervasive fluid flow of open system in crustal discontinuities. This process was prominent in the northern belt ( Sinec shear zone) located more closely to Veporic thermal dome, while towards its peripheral parts (southern Ochtina belt) the M2 metamorphic process and steatitization gradually weakened.Studies from Sinec shear zone (being the prominent AD2 -AD3 structure of northern Sinec belt) , where the dolomite/magnesite lenses (replacement in M1) and their accompanying lithology were in AD1 sandwitched between more competent basement blocks, proved in AD2 the pervasite steatitization, the talc and dolomite 2 origin in extensional microstructures ( metamorphic process M2; 490 -540℃, 240-330 MPa, 1. c. ).The economic accummulations of talc in Sinec belt are the products of antithetic shearing during the AD3 phase, being the gradual continuation of AD2 ( change of kinematics from unroofing to regional transpressional shearing). Contrary to the northern Sinec belt having located the AD3 deformation into narrow shear zone with soft lithology surrounded by hard lithology, in southern Ochtina belt the deformation AD3 was accommodated by wide soft rock column with rigid carbonate blocks floating inside. The lower P-T ( M2)conditions and deformational gradient in Ochtina belt during AD2 and AD3 phases caused why no economic talc accummulations developed there.The results of presented study can be used as general criteria for magnesite and talc prospection in Alpine type terranes.展开更多
The northern extension of the Semailophiolite in the UAE is dominated by tectonic mantle peridotites and gabbros. The peridotites are mostly harzburgites with little lherzolites, and contain various intermittentveins,...The northern extension of the Semailophiolite in the UAE is dominated by tectonic mantle peridotites and gabbros. The peridotites are mostly harzburgites with little lherzolites, and contain various intermittentveins, dikes and pods. These veins, dikes and pods can be divided into three rock categories: the ultramafic group that includes dunites, chromitites and pyroxenites, the granitic dikes, and carbonate veins. Occurrences of these bodies are explicit and ubiquitous, but their distribution throughout the sequence is not consistent. Pyroxenites, chromitites, and granites occur in the upper half of the sequence, but are more pronounced and dominant close to the transition zone. Dunites pods and carbonate veins can be found at different stratigraphic levels.展开更多
基金Project(BGRIMM-KJSKL-2024-07) supported by the Open Foundation of State Key Laboratory of Mineral Processing,ChinaProjects(52374259,52174239) supported by the National Natural Science Foundation of China。
文摘Surface pretreatment can change the surface properties of minerals,placing them in either a favorable or an unfavorable state for flotation.To solve the separation problem associated with magnesite and dolomite,surface pretreatment experiments with citric acid,tartaric acid,and tannic acid(TA)on magnesite and dolomite as well as flotation experiments on pretreated samples were performed in this study.Experimental results demonstrated that when citric acid and tartaric acid are used for surface pretreatment,the separation effect of magnesite and dolomite is poor.However,when TA is used,the separation effect of magnesite and dolomite improves.SEM and BET analysis indicated that surface pretreatment with TA changes the surface morphology of the two minerals,resulting in additional concave pores on the dolomite surface,and a significant increase in pore size and specific surface area.The adsorption quantity test and contact angle measurement demonstrated that after surface pretreatment with TA,the magnesite adsorption capacity on sodium oleate(NaOL)slightly decreases and the dolomite adsorption capacity on NaOL considerably decreases.XPS detection concluded that the surface pretreatment of TA on the magnesite surface mainly relies on physical adsorption with weak adsorption ability and poor ability to act on Mg sites.The TA surface pretreatment action on the dolomite surface is mainly through chemical adsorption,and it is strongly and selectively adsorbed on the Ca site of dolomite through O.Actual ore rough selection experiments reveal that TA pretreatment successfully removes dolomite from magnesite,resulting in a high-quality magnesite concentrate characterized by a MgO grade of 45.49%and a CaO grade of 0.75%.
文摘This paper summarizes recent data about magnesite and talc genesis in Carboniferous host rocks of Western Carpathians (Slovakia) , which occur in two distinct belts in tectonic superunit Veporicum and its contact zone with Gemericum. The northern Sinec magnesite and talc belt (with main deposits Kokava, Sinec, Samo, Hnust'a-Mutnik) contains economic accummulation of magnesite and talc, while in the southern Ochtina belt ( main deposits in Dubrava massif-Dubrava, Mikova, Jedl'ovec; Lubenik, Ochtina, Kosice-Bankov, Banisko, Medvedia) the magnesite is dominating.The magnesite genesis by successive replacement of Carboniferous calcite to dolomite and magnesite during metamorphic process Ml (northern belt 280-400℃; , southern belt 370-420℃: ; Radvanec & Prochaska, 2001; Kodera & Radvanec, 2002) , being supplied by Mg from Permoscythian evaporitic bittern brines, relates to Variscan post-collisional (post-VD) evolution. The extensional tectonics and the high heat flow facilitated the generation of a hydrothermal system.The time-separated later metamorphic and sourcely different fluid flow event (M2; 1. c. ) produced talc. Tectonic, microtectonic, metamorphic and geochronological data relate the talc origin with the Alpine Upper Cretaceous (88-84 Ma; Maluski in Kovacik et al. , 1996) tectonothermal event AD2. This event, being the consequence of Alpine collisional ( AD1 ) crustal thickening and metamorphic core complex origin, meant regional extension and pervasive fluid flow of open system in crustal discontinuities. This process was prominent in the northern belt ( Sinec shear zone) located more closely to Veporic thermal dome, while towards its peripheral parts (southern Ochtina belt) the M2 metamorphic process and steatitization gradually weakened.Studies from Sinec shear zone (being the prominent AD2 -AD3 structure of northern Sinec belt) , where the dolomite/magnesite lenses (replacement in M1) and their accompanying lithology were in AD1 sandwitched between more competent basement blocks, proved in AD2 the pervasite steatitization, the talc and dolomite 2 origin in extensional microstructures ( metamorphic process M2; 490 -540℃, 240-330 MPa, 1. c. ).The economic accummulations of talc in Sinec belt are the products of antithetic shearing during the AD3 phase, being the gradual continuation of AD2 ( change of kinematics from unroofing to regional transpressional shearing). Contrary to the northern Sinec belt having located the AD3 deformation into narrow shear zone with soft lithology surrounded by hard lithology, in southern Ochtina belt the deformation AD3 was accommodated by wide soft rock column with rigid carbonate blocks floating inside. The lower P-T ( M2)conditions and deformational gradient in Ochtina belt during AD2 and AD3 phases caused why no economic talc accummulations developed there.The results of presented study can be used as general criteria for magnesite and talc prospection in Alpine type terranes.
文摘The northern extension of the Semailophiolite in the UAE is dominated by tectonic mantle peridotites and gabbros. The peridotites are mostly harzburgites with little lherzolites, and contain various intermittentveins, dikes and pods. These veins, dikes and pods can be divided into three rock categories: the ultramafic group that includes dunites, chromitites and pyroxenites, the granitic dikes, and carbonate veins. Occurrences of these bodies are explicit and ubiquitous, but their distribution throughout the sequence is not consistent. Pyroxenites, chromitites, and granites occur in the upper half of the sequence, but are more pronounced and dominant close to the transition zone. Dunites pods and carbonate veins can be found at different stratigraphic levels.
