Final Report: The Characterization and Treatment of Hazardous Materials from Metal/Mineral Processing Wastes

EPA Grant Number: R825549C014
Subproject: this is subproject number 014 , established and managed by the Center Director under grant R825549
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC (1989) - Great Plains/Rocky Mountain HSRC
Center Director: Erickson, Larry E.
Title: The Characterization and Treatment of Hazardous Materials from Metal/Mineral Processing Wastes
Investigators: OKeefe, Thomas J. , Watson, John L.
Institution: Missouri University of Science and Technology
EPA Project Officer: Hahn, Intaek
Project Period: February 1, 1989 through September 1, 1991
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (1989) RFA Text |  Recipients Lists
Research Category: Heavy Metal Contamination of Soil/Water , Land and Waste Management


The purpose of this research project was to examine the applicability of hydrometallurgical and electrometallurgical techniques currently utilized in conventional extractive processes for the treatment of selected waste products. Typically flowsheets would include leaching, solution purification (especially solvent extraction), and electrowinning.

Summary/Accomplishments (Outputs/Outcomes):

Many of the waste products generated by the production of metals from ores in the U.S. have been stockpiled for significant periods of time. Typical examples of such products in the Midwest include steel furnace dusts, sludges and fumes, lead smelter slags, and zinc leach residues. These wastes often contain significant levels of lead, zinc, and cadmium, in addition to iron, and can be classified as hazardous materials. Currently treatment processes were investigated to identify techniques to:

1 ) render the materials non-hazardous to permit disposal in a safe, effective, and efficient manner; and
2) recover the metal values from the waste materials to provide revenue to fund the disposal process.

The processes selected for investigation included acid leaching (hydrometallurgy) followed by electrolytic reduction (electrometallurgy). The materials selected for the leaching research were lead blast furnace slags, after pretreatment by the FLAME REACTOR process, and steel electric arc furnace dusts, after pretreatment by the AUSMELT process. Both of these materials contained zinc, lead, and iron, and it was considered that a suitable flowsheet would permit the removal of zinc and lead from the waste by leaching, and the disposal of a non-hazardous residue. Finally the zinc, and possibly the lead, would be electrowon economically from the leach solution. Typically the leach solutions produced from these materials contain impurities and must be purified by a process, such as solvent extraction, prior to electrowinning. Thus, the effect of electrowinning metals from waste leach solutions, possibly contaminated with organic solvent, was also investigated.

Lead Blast Furnace Slag Treatment

Lead blast furnace slag, when treated by the Horsehead FLAME REACTOR process, generates an inert slag for disposal, and a zinc/lead/iron oxidized fume product. This multi-metal oxide was used as the starting material and investigated with respect to metal value recovery. It was determined that zinc was effectively recovered by sulfuric acid and hydrochloric acid leaching, but in both cases it was not possible to prevent large scale dissolution of iron from also occurring. Thus, a solution purification process to remove iron from the leach solution was deemed necessary to facilitate subsequent zinc electrowinning. Lead was essentially insoluble in sulfuric acid and only slightly soluble in hydrochloric acid, but was readily recovered, along with zinc and iron, with an acidified brine leach. A caustic leach was found to partially recover lead, but not zinc.

Overall, a flowsheet including a sulfuric acid leach to recover zinc, followed by an acidified brine leach to recover lead, was suggested. Significant solution purification, possibly by solvent extraction, would be necessary before either leach solution could be processed by electrowinning.

Neutral Leach Residue Treatment

Neutral zinc leach residue from the Big River Zinc Co., Sauget, IL, was treated in Australia by the AUSMELT process. An inert slag and a zinc/lead/iron oxide product is generated by this pyrometallurgical in-bath lance smelting process. The zinc oxide material was found to readily dissolve in sulfuric acid, but attempts to electrowin the solutions even after conventional cementation purification steps were disappointing. It was shown that the electrowinning process for such solutions was very susceptible to solution impurities and that careful control of solution additives was necessary to even approach the efficiencies common in conventional electrowinning. The value of polarization curves and current rise measurements in characterizing the electrowinning process was demonstrated.

Organic Entrainment Effects on Zinc Electrowinning

Solvent extraction effectively transfers zinc selectively from an aqueous leach solution to an organic solvent. The two phases are then physically separated. Next the zinc is stripped from the organic solvent using an acid electrolyte suitable for electrowinning. During solvent extraction, it is likely that some degree of organic phase entrainment will occur in the strip solution and thus the possible effect of this entrainment on the electrowinning process was investigated.

Using di-2-ethyl hexyl phosphoric acid as extractant in a kerosene diluent, it was demonstrated that organic entrainment from the solvent extraction purification step was detrimental to the electrowinning process. It was also shown that the entrained organic could be removed by activated carbon, with significant improvements then being noted in the efficiency of the electrowinning process.

In summary, the research project has provided insight into possible treatment flowsheets for metal recovery from zinc/lead/iron bearing waste products. The work is continuing in the areas of solvent extraction and electrowinning with a view to determining suitable process parameters, and conditions, to enable zinc and lead to be recovered effectively, preferably by existing processing units.

The results have been presented at professional meetings and to interested parties.

Journal Articles on this Report : 1 Displayed | Download in RIS Format

Other subproject views: All 4 publications 1 publications in selected types All 1 journal articles
Other center views: All 904 publications 230 publications in selected types All 182 journal articles
Type Citation Sub Project Document Sources
Journal Article Neira M, O'Keefe TJ, Watson JL. Solvent extraction reagent entrainment effects on zinc electrowinning from waste oxide leach solutions. Minerals Engineering 1992;5(3-5):521-534. R825549C014 (Final)
not available

Supplemental Keywords:

mineral processing, zinc, lead, cadmium., RFA, Scientific Discipline, Waste, Water, Geographic Area, Wastewater, Remediation, Environmental Chemistry, Geochemistry, Chemistry, Analytical Chemistry, Hazardous Waste, Ecology and Ecosystems, Hazardous, EPA Region, contaminated sediments, fate and transport, electrowinning, hazardous liquid waste, fate and transport , wastewater remediation, contaminated soil, Region 7, Region 8, contaminated groundwater, hazardous wate, electrolytic reduction, electrochemcial treatment, groundwater, heavy metals, mining wastes, aqueous waste stream

Relevant Websites: Exit

Progress and Final Reports:

Original Abstract
  • 1989
  • 1990

  • Main Center Abstract and Reports:

    R825549    HSRC (1989) - Great Plains/Rocky Mountain HSRC

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825549C006 Fate of Trichloroethylene (TCE) in Plant/Soil Systems
    R825549C007 Experimental Study of Stabilization/Solidification of Hazardous Wastes
    R825549C008 Modeling Dissolved Oxygen, Nitrate and Pesticide Contamination in the Subsurface Environment
    R825549C009 Vadose Zone Decontamination by Air Venting
    R825549C010 Thermochemical Treatment of Hazardous Wastes
    R825549C011 Development, Characterization and Evaluation of Adsorbent Regeneration Processes for Treament of Hazardous Waste
    R825549C012 Computer Method to Estimate Safe Level Water Quality Concentrations for Organic Chemicals
    R825549C013 Removal of Nitrogenous Pesticides from Rural Well-Water Supplies by Enzymatic Ozonation Process
    R825549C014 The Characterization and Treatment of Hazardous Materials from Metal/Mineral Processing Wastes
    R825549C015 Adsorption of Hazardous Substances onto Soil Constituents
    R825549C016 Reclamation of Metal and Mining Contaminated Superfund Sites using Sewage Sludge/Fly Ash Amendment
    R825549C017 Metal Recovery and Reuse Using an Integrated Vermiculite Ion Exchange - Acid Recovery System
    R825549C018 Removal of Heavy Metals from Hazardous Wastes by Protein Complexation for their Ultimate Recovery and Reuse
    R825549C019 Development of In-situ Biodegradation Technology
    R825549C020 Migration and Biodegradation of Pentachlorophenol in Soil Environment
    R825549C021 Deep-Rooted Poplar Trees as an Innovative Treatment Technology for Pesticide and Toxic Organics Removal from Soil and Groundwater
    R825549C022 In-situ Soil and Aquifer Decontaminaiton using Hydrogen Peroxide and Fenton's Reagent
    R825549C023 Simulation of Three-Dimensional Transport of Hazardous Chemicals in Heterogeneous Soil Cores Using X-ray Computed Tomography
    R825549C024 The Response of Natural Groundwater Bacteria to Groundwater Contamination by Gasoline in a Karst Region
    R825549C025 An Electrochemical Method for Acid Mine Drainage Remediation and Metals Recovery
    R825549C026 Sulfide Size and Morphology Identificaiton for Remediation of Acid Producing Mine Wastes
    R825549C027 Heavy Metals Removal from Dilute Aqueous Solutions using Biopolymers
    R825549C028 Neutron Activation Analysis for Heavy Metal Contaminants in the Environment
    R825549C029 Reducing Heavy Metal Availability to Perennial Grasses and Row-Crops Grown on Contaminated Soils and Mine Spoils
    R825549C030 Alachlor and Atrazine Losses from Runoff and Erosion in the Blue River Basin
    R825549C031 Biodetoxification of Mixed Solid and Hazardous Wastes by Staged Anaerobic Fermentation Conducted at Separate Redox and pH Environments
    R825549C032 Time Dependent Movement of Dioxin and Related Compounds in Soil
    R825549C033 Impact of Soil Microflora on Revegetation Efforts in Southeast Kansas
    R825549C034 Modeling the use of Plants in Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances
    R825549C035 Development of Electrochemical Processes for Improved Treatment of Lead Wastes
    R825549C036 Innovative Treatment and Bank Stabilization of Metals-Contaminated Soils and Tailings along Whitewood Creek, South Dakota
    R825549C037 Formation and Transformation of Pesticide Degradation Products Under Various Electron Acceptor Conditions
    R825549C038 The Effect of Redox Conditions on Transformations of Carbon Tetrachloride
    R825549C039 Remediation of Soil Contaminated with an Organic Phase
    R825549C040 Intelligent Process Design and Control for the Minimization of Waste Production and Treatment of Hazardous Waste
    R825549C041 Heavy Metals Removal from Contaminated Water Solutions
    R825549C042 Metals Soil Pollution and Vegetative Remediation
    R825549C043 Fate and Transport of Munitions Residues in Contaminated Soil
    R825549C044 The Role of Metallic Iron in the Biotransformation of Chlorinated Xenobiotics
    R825549C045 Use of Vegetation to Enhance Bioremediation of Surface Soils Contaminated with Pesticide Wastes
    R825549C046 Fate and Transport of Heavy Metals and Radionuclides in Soil: The Impacts of Vegetation
    R825549C047 Vegetative Interceptor Zones for Containment of Heavy Metal Pollutants
    R825549C048 Acid-Producing Metalliferous Waste Reclamation by Material Reprocessing and Vegetative Stabilization
    R825549C049 Laboratory and Field Evaluation of Upward Mobilization and Photodegradation of Polychlorinated Dibenzo-P-Dioxins and Furans in Soil
    R825549C050 Evaluation of Biosparging Performance and Process Fundamentals for Site Remediation
    R825549C051 Field Scale Bioremediation: Relationship of Parent Compound Disappearance to Humification, Mineralization, Leaching, Volatilization of Transformaiton Intermediates
    R825549C052 Chelating Extraction of Heavy Metals from Contaminated Soils
    R825549C053 Application of Anaerobic and Multiple-Electron-Acceptor Bioremediation to Chlorinated Aliphatic Subsurface Contamination
    R825549C054 Application of PGNAA Remote Sensing Methods to Real-Time, Non-Intrusive Determination of Contaminant Profiles in Soils
    R825549C055 Design and Development of an Innovative Industrial Scale Process to Economically Treat Waste Zinc Residues
    R825549C056 Remediation of Soils Contaminated with Wood-Treatment Chemicals (PCP and Creosote)
    R825549C057 Effects of Surfactants on the Bioavailability and Biodegradation of Contaminants in Soils
    R825549C058 Contaminant Binding to the Humin Fraction of Soil Organic Matter
    R825549C059 Identifying Ground-Water Threats from Improperly Abandoned Boreholes
    R825549C060 Uptake of BTEX Compounds by Hybrid Poplar Trees in Hazardous Waste Remediation
    R825549C061 Biofilm Barriers for Waste Containment
    R825549C062 Plant Assisted Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances: Experimental and Modeling Studies
    R825549C063 Extension of Laboratory Validated Treatment and Remediation Technologies to Field Problems in Aquifer Soil and Water Contamination by Organic Waste Chemicals