Characterisation of Mining and Industrial By-Products with Potential for Use as Environmental Amendments Laura Wendling, Grant Douglas and Shandel Coleman Water for a Healthy Country Flagship Report June 2009 Characterisation of Industrial By-Products with Potential for Use as Environmental Amendments Water for a Healthy Country Flagship Report series ISSN: 1835-095X Australia is founding its future on science and innovation. Its national science agency, CSIRO, is a powerhouse of ideas, technologies and skills. CSIRO initiated the National Research Flagships to address Australia’s major research challenges and opportunities. They apply large scale, long term, multidisciplinary science and aim for widespread adoption of solutions. The Flagship Collaboration Fund supports the best and brightest researchers to address these complex challenges through partnerships between CSIRO, universities, research agencies and industry. The Water for a Healthy Country Flagship aims to achieve a tenfold increase in the economic, social and environmental benefits from water by 2025. The work contained in this report is collaboration between CSIRO and the Western Australian Water Foundation, Iluka Resources, Ltd and the WA Department of Water. For more information about Water for a Healthy Country Flagship or the National Research Flagship Initiative visit www.csiro.au/org/HealthyCountry.html Citation: Wendling, L., G. Douglas and S. Coleman, 2009. Characterisation of Mining and Industrial By-Products with Potential for Use as Environmental Amendments. CSIRO: Water for a Healthy Country National Research Flagship. Copyright and Disclaimer © 2009 CSIRO To the extent permitted by law, all rights are reserved and no part of this publication covered by copyright may be reproduced or copied in any form or by any means except with the written permission of CSIRO. Important Disclaimer: CSIRO advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, CSIRO (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. The views expressed are not necessarily the views of the Government of Western Australia, the Department of Water nor the Water Foundation. Cover Photograph: Description: Bauxite mining machinery, Southwest WA. 1977. Photographer: Willem van Aken © 2009 CSIRO Characterisation of Industrial By-Products with Potential for Use as Environmental Amendments ACKNOWLEDGEMENTS The authors gratefully acknowledge Iluka Resources, Ltd., Rio Tinto HIsmelt and the Western Australian Government for support provided through the Water Foundation and the Department of Water. We would also like to formally acknowledge: Mark Raven for X-ray diffraction and X-ray fluorescence analyses; Chris Leslie and Gary Hancock for radioactivity analyses; and the staff from Genalysis Laboratories and the Chemistry Centre of WA for meeting sometimes demanding deadlines for sample analysis. Characterisation of Industrial By-Products with Potential for Use as Environmental Amendments Page iii EXECUTIVE SUMMARY Contaminant removal from natural and waste waters, and amelioration of acidity in both water and soils are core environmental management priorities for a sustainable Western Australia. The goal of the project “Wastewater purification and re-use: Mineral-based sorbents for contaminant removal” (PWF 009-05) is to source and characterize a suite of abundant industrial by-products, principally from Western Australia, with the specific aim of identifying by-product materials “fit for purpose” for specific environmental applications. This report describes the characterisation of by- products to be examined in further studies. • Effective removal of nutrients and trace metals from industrial, agricultural and domestic wastewater is pivotal to water re-use. Utilisation of abundant, low-cost industrial by- product materials potentially offers a cost-effective wastewater treatment option. We examined the potential re-use of largely unexploited mineral processing materials in Western Australia as “designer” contaminant adsorbents. This work is underlain by a “wealth from waste” strategy aligning the productive re-use of solid by-product materials to treat wastewater previously discarded or treated by less efficient or more costly means. • One of Western Australia’s most pressing environmental concerns involves the highly acidic, hypersaline drainage waters from the WA Wheatbelt. Feasible management options for treatment of WA Wheatbelt drainage waters may include the use of industrial by-products as surface water amendments, within-drain filtration/treatment systems, and/or permeable reactive barriers. The main advantages to using industrial by-products as environmental amendments are economic viability (low cost) and waste reduction. • A number of industrial by-products are readily available in WA and possess characteristics indicative of potential benefit as soil or surface water amendments, including the heavy minerals processing residue neutralised unused acid (NUA), red mud, red sand, flue gas desulphurisation gypsum, cement kiln dust, steelmaking by- products, fly ash, calcined magnesia and water treatment residue. • Natural mineral amendments such as mine overburden, carbonates or carbonate derivatives (e.g. limestone, lime, dolomite), phyllosilicate (clay) minerals, zeolite minerals and/or hydrotalcite minerals could also be used in conjunction with low-cost industrial by- products to ameliorate acidity and attenuate potentially toxic metals and excess nutrients in effluent waters. • This report details the physical, mineralogical, chemical, radiological and toxicological properties of some mineral-based by-products, principally from WA, and provides information necessary to assess the potential suitability of each material for use in further trials (Table 1). The materials examined include a heavy minerals processing residue (neutralised unused acid, NUA), a by-product of iron-ore processing (steelmaking by- product), by-products generated during Bayer process alumina production and their derivatives (red mud, red sand, and reduced red sand), lime- and CaCO3-based residues from metropolitan groundwater treatment plants, and a by-product of coal-based energy production (fly ash). Other materials of interest that are available on a large scale and had potentially useful properties either by themselves or if blended with by-products including laterite, calcined magnesia, and a carbonized wood product (granular activated carbon) were also included in this study. • Based on their Ca, Fe and/or Al content, red mud, red sand, reduced red sand, steelmaking by-product, NUA, fly ash and lime- or CaCO3-based groundwater treatment plant residues may have a high anion uptake capacity and thus a substantial capacity for the uptake of P or dissolved organic carbon (DOC). These materials may be suited to the removal of excess P from surface waters, such as Ellen Brook, or wastewater streams. • By-products comprised of substantial quantities of poorly crystalline Fe/Al/Mn (oxy)hydroxide minerals (e.g., ferrihydrite) may be useful for sorption of metals. Of the by- Characterisation of Industrial By-Products with Potential for Use as Environmental Amendments Page iv products or other materials examined herein, red mud, red sand, reduced red sand, NUA and laterite may be suitable for metal sorption. • Radiological analyses and calculated absorbed dose rates (D) indicate that some of the materials examined exhibited radioactivities greater than the UNSCEAR guideline D of 11-54 nGy h-1. However, all by-product D values were less than or comparable to those reported for phosphogypsum fertiliser, and the highest calculated absorbed dose rates for by-products were comparable to those determined for WA’s Darling Scarp soils. Results indicate that these materials may require dilution to improve suitability for environmental application, dependent on radionuclide speciation and mobility. • By-products such as calcined magnesia, red mud, steelmaking by-product, and fly ash have high acid neutralisation capacity and may be suited for remediation of acidic drainage waters of the WA Wheatbelt. Further detailed study is, however, required to quantify the efficacy of acid neutralisation of and removal of potentially toxic elements from drainage waters, to fully characterise the geochemical interactions between potential receiving waters and each by-product or other materials, and to analyse resultant waters/leachate for potential toxicity prior to field trials or full-scale environmental applications. Characterisation of Industrial By-Products with Potential for Use as Environmental Amendments Page v Table 1. General assessment of characteristics of materials examined that are pertinent to reuse as soil amendments or in water treatment schemes. A = within acceptable range; L = low; H = high. ND = not determined. Values in red fall outside acceptable ranges. Chemistry Radioactivity4