Treatment of Arsenic-Bearing Minerals and Fixation of Recovered Arsenic Products: An Updated Review

Mineral processing and extractive metallurgical operations have created and are creating appreciable arsenic bearing wastewater and waste solid products that have to be handled, treated for recycle, or treated for environmentally safe disposal. At present there are intense research and operational activities being conducted to provide the best viable processing procedures to ensure that the mineral processing and extractive metallurgical industries are profitable and environmentally secure. The focus of this presentation is on the element arsenic, even though many other deleterious elements may also be present in ores and concentrates. Numerous base metal resources contain arsenic bearing minerals, especially resources containing mineral sulfides. Information on presently treated metal-bearing resources and potential new resources is voluminous, especially for those containing arsenic mineralization. The influence of elevated arsenic concentrations in the treatment of copper-arsenic sulfides and to a lesser extent the treatment of copper-gold-arsenic sulfides are considered in this presentation. Because of chapter page limitations not all treatment processes are discussed, however, examples are provided to illustrate arsenic problems and industrial solutions. The major emphasis of this presentation has been placed on the present state-of-the-art for arsenic immobilization/fixation and long-term storage considerations

A GUIDE to FIFTY YEARS of RESEARCH at MONTANA TECH: Part 2 THE TREATMENT of ELECTROPLATING and ELECTROMACHINING METAL HYDROXIDE SLUDGE for the RECOVERY of METAL VALUES [see also Part 1)

ABSTRACT and FORWARD The treatment and recovery of metal species from hydrometallurgical solutions and wastewater solids has been and continues to be an important research topic. This presentation includes a guide to the literature with a summary discussion of the research conducted at Montana Tech in the Department of Metallurgical and Materials Engineering during the 1984-2001 period. A previous presentation (Part 1) focused on the removal of arsenic, selenium, and other species by hydrometallurgical processes and the formation of environmentally stable disposable products. This guide is available at the reference presented above. This following presentation (Part 2) is based on the research of Master of Science graduate students (13), industrial (3) and academic colleagues (4), at the Montana College of Mineral Science and Technology (which morphed to Montana Tech [1977], then to Montana Tech of The University of Montana [2000], then to Montana Technological University [2019). The referenced research of each of the graduate students (13) in this presentation is gratefully acknowledged. The following summary does not include other research studies conducted in the Metallurgy/Materials Engineering Department by other teaching and research colleagues. See Appendix C for a list of the Master of Science research thesis students and their research topics highlighting their contributions to our departments’ research efforts (student theses are readily available, on-line in digital format, at the Montana Tech Library). The referenced research discussed (and annotated) in this report was supported by the U.S. Environmental Protection Agency (EPA) over a period of ten years

A GUIDE TO FIFTY YEARS OF RESEARCH AT MONTANA TECH: Part 1-THE TREATMENT OF ARSENIC, SELENIUM, THALLIUM, METAL BEARING SOLUTIONS AND WASTE SOLIDS

ABSTRACT and FORWARD The removal of arsenic, selenium, and metal species from hydrometallurgical solutions and wastewaters has been and continues to be an important research topic. This presentation includes a discussion of the research conducted at Montana Tech in the Department of Metallurgical and Materials Engineering during the past fifty years. The discussion is focused on removal of arsenic by co-precipitation with Fe(III) and Fe(II), co-precipitation with Fe(III) and Al(III), reduction using elemental iron; the removal of selenium by elemental iron and catalysed iron; and the removal of cadmium, copper, nickel, zinc by co-precipitation with Fe(III) and Al(III). This presentation is based on the research of Master of Science graduate students, industrial and academic colleagues, at the Montana College of Mineral Science and Technology (which morphed to Montana Tech [1977], then to Montana Tech of The University of Montana [2000], then to Montana Technological University [2019]). The referenced work of each of the graduate students in this presentation is gratefully acknowledged. The following summary does not include other research studies conducted in the Metallurgy/Materials Engineering Department by other teaching and research colleagues (except for some of the work supervised by Dr. Hsin Huang). See Appendix A for a list of the Master of Science research thesis students (11) and their research topics highlighting their contributions to our departments’ research efforts (student theses are readily available, on-line in digital format, at the Montana Tech Library). The referenced research was supported by the U.S. Environmental Protection Agency Mine Waste Treatment Program (EPA-MWTP), the National Science Foundation, and the Center for Advanced Metallurgical and Mineral Processing (CAMP) over a period of ten years. Because of our extensive arsenic research, I have included a recent detailed annotated literature survey of the topic “Fixation of Arsenic (August 2021)” prior to presenting a summary of the Twidwell group’s specific research studies and results at Montana Tech. The reader may bypass the literature survey by going to page 32 for a summary of Montana Tech research studies and results