{"id":{"repo_id":"colo-mines","oai_identifier":"oai:repository.mines.edu:11124/78759"},"canonical_url":"https://search.dev.ndltd.org/etd/colo-mines/oai:repository.mines.edu:11124/78759","repository":{"repo_id":"colo-mines","name":"Colorado School of Mines","base_url":"https://repository.mines.edu/server/oai/request"},"display":{"title":"On the leaching behavior of uranium-bearing resources in carbonate-bicarbonate solution by gaseous oxidants","abstract":"Uranium is recognized to be a critical commodity in the context of satisfying the global energy-demands for the twenty-first century and beyond. In 2013, a significant supply gap of 17% between worldwide production and consumption of uranium was identified. Consequently, low-grade uranium-bearing limestone rock, including mining waste, may represent a significant future uranium-resource, provided an economically-viable method of extraction is developed. Alkaline leaching of uranium from limestone media has been practiced extensively in the past; however, cutting-edge research during the last 20 years has been rather meager. The research reported in this thesis is an investigation into the use of an alternative gaseous oxidant (oxygen/ozone), which may serve to improve the economics of alkaline leaching; specifically, heap leaching. Components of the research include the employment of computational software (PHREEQ), which allowed the equilibrium distribution of the aquo-species in solution to be determined, as well as solubility behavior of candidate condensed-species (precipitates). Also, two suites of leaching experiments were performed, one with synthetic UO2 particles, which served as a model system, and the other with comminuted uranium-bearing Todilto limestone. The aqueous-phase lixiviant for each was comprised of 40 gpl Na2CO3 and 15 gpl NaHCO3. The invariant leaching-configuration was: continuously-stirred batch-reactor with the ratio of uranium-bearing particulate-source to aqueous-phase such that a hypothetical-maximum uranium concentration in solution of 1.0 gpl (~0.0040 molar) could be achieved. The duration of the two suites of experiments was 48-hours and 72-hours, respectively. A robust two-parameter non-linear function, Recovery (%) = 100 [1- exp(-a *(t^b)], was formulated to regress (smooth) the data acquired from the leaching experiments. The regressed-equations (containing optimal values for the parameters \"a\" and \"b\") served as a quantitative tool for relative assessment of the leaching-rate characteristics of each member-experiment within a suite of experiments performed. The work reported in this thesis is considered to be a significant contribution to the knowledge-base required for planning cost-effective strategies for uranium recovery from low-grade alkaline uranium-bearing resources. Additionally, it provides process-engineers with information for developing appropriate recovery-methods (flowsheets), while at the same time being able to assess potential environmental impacts.","abstract_html":"Uranium is recognized to be a critical commodity in the context of satisfying the global energy-demands for the twenty-first century and beyond. In 2013, a significant supply gap of 17% between worldwide production and consumption of uranium was identified. Consequently, low-grade uranium-bearing limestone rock, including mining waste, may represent a significant future uranium-resource, provided an economically-viable method of extraction is developed. Alkaline leaching of uranium from limestone media has been practiced extensively in the past; however, cutting-edge research during the last 20 years has been rather meager. The research reported in this thesis is an investigation into the use of an alternative gaseous oxidant (oxygen/ozone), which may serve to improve the economics of alkaline leaching; specifically, heap leaching. Components of the research include the employment of computational software (PHREEQ), which allowed the equilibrium distribution of the aquo-species in solution to be determined, as well as solubility behavior of candidate condensed-species (precipitates). Also, two suites of leaching experiments were performed, one with synthetic UO2 particles, which served as a model system, and the other with comminuted uranium-bearing Todilto limestone. The aqueous-phase lixiviant for each was comprised of 40 gpl Na2CO3 and 15 gpl NaHCO3. The invariant leaching-configuration was: continuously-stirred batch-reactor with the ratio of uranium-bearing particulate-source to aqueous-phase such that a hypothetical-maximum uranium concentration in solution of 1.0 gpl (~0.0040 molar) could be achieved. The duration of the two suites of experiments was 48-hours and 72-hours, respectively. A robust two-parameter non-linear function, Recovery (%) = 100 [1- exp(-a *(t^b)], was formulated to regress (smooth) the data acquired from the leaching experiments. The regressed-equations (containing optimal values for the parameters "a" and "b") served as a quantitative tool for relative assessment of the leaching-rate characteristics of each member-experiment within a suite of experiments performed. The work reported in this thesis is considered to be a significant contribution to the knowledge-base required for planning cost-effective strategies for uranium recovery from low-grade alkaline uranium-bearing resources. Additionally, it provides process-engineers with information for developing appropriate recovery-methods (flowsheets), while at the same time being able to assess potential environmental impacts.","abstract_has_math":false,"creators":["Hunter, Erik"],"institution":"Colorado School of Mines. Arthur Lakes Library","degree_name":"Doctor of Philosophy (Ph.D.)","degree_level":"Doctoral","degree_discipline":"Mining Engineering","degree_department":null,"school":null,"contributors":[],"advisors":["Kuchta, Mark","Figueroa, Linda A."],"committee_chairs":[],"committee_members":["Martins, Gerard P.","Dagdelen, Kadri","Miller, Hugh B.","King, Jeffrey C."],"year":2013,"date_issued":"2013","date_published":"2013","updated_at":"2026-07-24T01:43:42Z","subjects":["heap leaching","geology","uranium","ozone","mining","metallurgy"],"languages":["eng","English"],"rights":["Copyright of the original work is retained by the author."],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["T 7226"],"render_values":[{"text":"T 7226","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/11124/78759","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Kuchta, Mark","Figueroa, Linda A."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Martins, Gerard P.","Dagdelen, Kadri","Miller, Hugh B.","King, Jeffrey C."]},{"key":"dc:creator","label":"Author","values":["Hunter, Erik"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2007-01-03T04:53:41Z","2022-02-09T08:51:30Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2007-01-03T04:53:41Z","2022-02-09T08:51:30Z"]},{"key":"dc:date.issued","label":"Date","values":["2013"]},{"key":"dc:publisher","label":"Institution","values":["Colorado School of Mines. 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In 2013, a significant supply gap of 17% between worldwide production and consumption of uranium was identified. Consequently, low-grade uranium-bearing limestone rock, including mining waste, may represent a significant future uranium-resource, provided an economically-viable method of extraction is developed. Alkaline leaching of uranium from limestone media has been practiced extensively in the past; however, cutting-edge research during the last 20 years has been rather meager. The research reported in this thesis is an investigation into the use of an alternative gaseous oxidant (oxygen/ozone), which may serve to improve the economics of alkaline leaching; specifically, heap leaching. Components of the research include the employment of computational software (PHREEQ), which allowed the equilibrium distribution of the aquo-species in solution to be determined, as well as solubility behavior of candidate condensed-species (precipitates). Also, two suites of leaching experiments were performed, one with synthetic UO2 particles, which served as a model system, and the other with comminuted uranium-bearing Todilto limestone. The aqueous-phase lixiviant for each was comprised of 40 gpl Na2CO3 and 15 gpl NaHCO3. The invariant leaching-configuration was: continuously-stirred batch-reactor with the ratio of uranium-bearing particulate-source to aqueous-phase such that a hypothetical-maximum uranium concentration in solution of 1.0 gpl (~0.0040 molar) could be achieved. The duration of the two suites of experiments was 48-hours and 72-hours, respectively. A robust two-parameter non-linear function, Recovery (%) = 100 [1- exp(-a *(t^b)], was formulated to regress (smooth) the data acquired from the leaching experiments. The regressed-equations (containing optimal values for the parameters \"a\" and \"b\") served as a quantitative tool for relative assessment of the leaching-rate characteristics of each member-experiment within a suite of experiments performed. The work reported in this thesis is considered to be a significant contribution to the knowledge-base required for planning cost-effective strategies for uranium recovery from low-grade alkaline uranium-bearing resources. Additionally, it provides process-engineers with information for developing appropriate recovery-methods (flowsheets), while at the same time being able to assess potential environmental impacts."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["born digital","doctoral dissertations"]},{"key":"dc:title","label":"Title","values":["On the leaching behavior of uranium-bearing resources in carbonate-bicarbonate solution by gaseous oxidants"]}]}],"canonical_facts":{"dc:contributor.advisor":["Kuchta, Mark","Figueroa, Linda A."],"dc:contributor.committeemember":["Martins, Gerard P.","Dagdelen, Kadri","Miller, Hugh B.","King, Jeffrey C."],"dc:creator":["Hunter, Erik"],"dc:date.accessioned":["2007-01-03T04:53:41Z","2022-02-09T08:51:30Z"],"dc:date.available":["2007-01-03T04:53:41Z","2022-02-09T08:51:30Z"],"dc:date.issued":["2013"],"dc:description":["2013 Spring.","Includes illustrations (some color), color map.","Includes bibliographical references (pages 150-161)."],"dc:description.abstract":["Uranium is recognized to be a critical commodity in the context of satisfying the global energy-demands for the twenty-first century and beyond. In 2013, a significant supply gap of 17% between worldwide production and consumption of uranium was identified. Consequently, low-grade uranium-bearing limestone rock, including mining waste, may represent a significant future uranium-resource, provided an economically-viable method of extraction is developed. Alkaline leaching of uranium from limestone media has been practiced extensively in the past; however, cutting-edge research during the last 20 years has been rather meager. The research reported in this thesis is an investigation into the use of an alternative gaseous oxidant (oxygen/ozone), which may serve to improve the economics of alkaline leaching; specifically, heap leaching. Components of the research include the employment of computational software (PHREEQ), which allowed the equilibrium distribution of the aquo-species in solution to be determined, as well as solubility behavior of candidate condensed-species (precipitates). Also, two suites of leaching experiments were performed, one with synthetic UO2 particles, which served as a model system, and the other with comminuted uranium-bearing Todilto limestone. The aqueous-phase lixiviant for each was comprised of 40 gpl Na2CO3 and 15 gpl NaHCO3. The invariant leaching-configuration was: continuously-stirred batch-reactor with the ratio of uranium-bearing particulate-source to aqueous-phase such that a hypothetical-maximum uranium concentration in solution of 1.0 gpl (~0.0040 molar) could be achieved. The duration of the two suites of experiments was 48-hours and 72-hours, respectively. A robust two-parameter non-linear function, Recovery (%) = 100 [1- exp(-a *(t^b)], was formulated to regress (smooth) the data acquired from the leaching experiments. The regressed-equations (containing optimal values for the parameters \"a\" and \"b\") served as a quantitative tool for relative assessment of the leaching-rate characteristics of each member-experiment within a suite of experiments performed. The work reported in this thesis is considered to be a significant contribution to the knowledge-base required for planning cost-effective strategies for uranium recovery from low-grade alkaline uranium-bearing resources. Additionally, it provides process-engineers with information for developing appropriate recovery-methods (flowsheets), while at the same time being able to assess potential environmental impacts."],"dc:format.medium":["born digital","doctoral dissertations"],"dc:identifier":["T 7226"],"dc:identifier.uri":["https://hdl.handle.net/11124/78759"],"dc:language":["English"],"dc:language.iso":["eng"],"dc:publisher":["Colorado School of Mines. Arthur Lakes Library"],"dc:rights":["Copyright of the original work is retained by the author."],"dc:subject":["heap leaching","geology","uranium","ozone","mining","metallurgy"],"dc:title":["On the leaching behavior of uranium-bearing resources in carbonate-bicarbonate solution by gaseous oxidants"],"dc:type":["Text"],"thesis:degree_discipline":["Mining Engineering"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["Doctor of Philosophy (Ph.D.)"],"thesis:institution_name":["Colorado School of Mines"]},"updated_at":"2026-07-24T01:43:42Z"}