Flow Injection Analysis of MWC Fly Ash Leaching Characteristics |
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Authors: | John A Willemin Carl C Nesbitt George R Dewey John F Sandell Lawrence L Sutler |
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Institution: | 1. Mid-State Associates, Inc. , Baraboo , Wisconsin , USA;2. Department of Metallurgical and Materials Engineering , Michigan Technological University , Houghton , Michigan , USA;3. Department of Civil and Environmental Engineering , Michigan Technological University , Houghton , Michigan , USA |
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Abstract: | Abstract A completely mixed batch reactor leaching method utilizing flow injection analysis (the CMBR-FIA method) was developed to study the lead leaching characteristics of municipal waste combustor fly ash. Flow injection analysis (FIA) coupled with atomic absorption spectrophotometry enabled the determination of lead concentrations at one minute intervals. The pH and oxidation-reduction potential of the solution were continuously monitored to characterize the leaching conditions. Automatic titration was used to alter the solution pH to defined endpoints. The CMBR-FIA method offers the ability to immediately observe alterations to the leaching solution, and grants the freedom to study a number of parameters concurrently. The CMBR-FIA method is a rapid and reliable means to investigate leaching characteristics. This paper describes the method and demonstrates its use to monitor the leaching of lead from municipal solid waste combustor fly ash as a function of pH. Soluble lead concentrations are shown to increase quickly with decreasing pH. A maximum of 50% of the total lead concentration was available in solution at pH 2. This value gradually decreased with time to over 35% of the total. |
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