铀矿地质2025，Vol.41Issue(2)：215-227,13.DOI:10.3969/j.issn.1000-0658.2025.41.016
鄂尔多斯盆地北缘砂岩型铀矿含矿砂岩中钛铁矿蚀变及其吸附-催化还原聚铀新机制
Ilmenite Alteration and Its Adsorption-Catalytic Reduction for U Enrichment of Sandstone-hosted U Deposits in the Northern Ordos Basin,North China
摘要
Abstract
In order to investigate the alteration process of ilmenite in sandstone-hosted uranium(U)deposits and its role in U mineralization,this study focuses on the deposits in the northern Ordos Basin,with advanced micro-area analysis techniques.Detailed analyses were conducted on ilmenite alteration products in ore-bearing sandstones,examining their spatial relationships with U minerals.Research shows that ilmenite in ore-bearing sandstone have underwent different degree of alteration along its edges,in the fractures and its core and forming leucoxene or anatase and locally visible pyrite in shape of strawberry and colloid.U minerals closely related to altered ilmenite are dominated by coffinite,which grows around leucoxene or anatase in the form of burrs and fine columns,or forms a large number of knitted aggregates of uranium minerals in the altered cavities of ilmenite.The U mineral can be divided into uraniferous leucoxene(I),titaniferous coffinite(I),and uraninite(II),indicating that the formation of U mineralization related to ilmenite alteration can be divided into two stages.The adsorption-autocatalytic reduction mechanism of U accumulation of altered ilmenite in sandstone-hosted U deposits was proposed through experimental studies of TiO₂-facilitated U aggregation with and without lightening.Combined with the study of the alteration process of ilmenite in ore-host sandstone,the U enrichment mechanism of ilmenite alteration was divided into ilmenite alteration and pre enrichment of U by adsorption and autocatalytic reduction by TiO2(leucoxene or anatase).The former emphasized the adsorption of porous leucoxene on U(Ⅵ)in a weak acidic environment.The latter believes that the β and γ X-rays produced in the decay of adsorbed uranium can provide energy for the catalytic reduction reaction of TiO2 and reduce U(Ⅵ)in the ore-forming fluid to U(Ⅳ).This catalytic reduction provides a novel pathway for U precipitation which will enhance the understanding of U enrichment mechanisms in sandstone-hosted deposits.关键词
砂岩型铀矿/钛铁矿蚀变/白钛石与锐钛矿/吸附-自催化还原/鄂尔多斯盆地Key words
sandstone-hosted U deposits/ilmenite alteration/leucoxene and anatase/adsorption and catalytic reduction/Ordos Basin分类
地质学引用本文复制引用
丁波,刘红旭,王文全,邱林飞..鄂尔多斯盆地北缘砂岩型铀矿含矿砂岩中钛铁矿蚀变及其吸附-催化还原聚铀新机制[J].铀矿地质,2025,41(2):215-227,13.基金项目
铀资源探采与核遥感全国重点实验室基金(编号:NKLUR-2024-ZD-001) （编号:NKLUR-2024-ZD-001）
中核集团基础研究项目(编号:地JCYJ2401) （编号:地JCYJ2401）
中国核工业地质局项目(编号:D2414)联合资助. （编号:D2414）
