TY - JOUR A1 - Bandow, Nicole A1 - Finkel, M. A1 - Grathwohl, P. A1 - Kalbe, Ute T1 - Influence of flow rate and particle size on local equilibrium in column percolation tests using crushed masonry T2 - Journal of Material Cycles and Waste Management N2 - Column leaching tests are frequently used and accepted for investigation of release of hazardous substances from solid materials. Independent of differences due to the field of application or national regulations, column tests assume that local equilibrium is established in the experiment which facilitates transfer of results to field conditions. In the process of harmonization and standardization within Europe the question on the influence of flow rate and grain size distribution on the local equilibrium was raised. Thus, a set of experiments using two different masonry materials with varying grain size distribution and flow rate were conducted including stop/flow experiments. Results are compared to a numerical model which takes intraparticle pore diffusion-controlled release of Mo and V into the percolating water into account. Due to the relatively high intraparticle porosity of the materials (24ā€“29%) data and model indicate that initially equilibrium-state conditions prevail followed by rapidly decreasing concentrations. The model fits data for Mo and V reasonably well; however, after the initial decline of concentrations (at L/Sā€‰>ā€‰2) extended tailing is observed especially of elements occurring as oxides, which is not captured by the model. PB - Springer Japan KW - Leaching KW - Porosity KW - Stop/flow experiments model KW - Intraparticle diffusion KW - Vanadium KW - Molybdenum PY - 2019 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/47265 AN - OPUS4-47265 SN - 1438-4957 SN - 1611-8227 VL - 21 IS - 3 SP - 642 EP - 651 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany