文献类型：期刊文献

英文题名：Chemistry and Transport of Potassium during the Non-Steady State of Syenite Leaching

作者：Li, Kejing[1];Dawydiak, Christi A.[2]

机构：[1]East China Univ Sci & Technol, Sch Chem Engn, Shanghai 200237, Peoples R China;[2]MIT, Dept Chem Engn, Cambridge, MA 02139 USA

年份：2017

卷号：81

期号：1

起止页码：29

外文期刊名：SOIL SCIENCE SOCIETY OF AMERICA JOURNAL

收录：;EI(收录号：20171003423291);WOS:【SCI-EXPANDED(收录号:WOS:000396377400004)】；

基金：The funding and materials of this research was provided by Terrativa Minerais S.A. Inc. through Materials Processing Center of Massachusetts Institute of Technology. The authors thank Prof. Antoine Allanore for all the equipment support and insightful discussions, Dr. Taisiya V. Skorina for the BET measurement, Dr. Rebecca Stokes for the XRD measurement, and Mr. Aron Downward for part of the ICP-MS measurement. They also appreciate the financial support from the Fundamental Research Funds for the Central Universities (22A20154009) and MIT UROP program.

语种：英文

外文关键词：Ion exchange - Mass spectrometry - Packed beds - Feldspar - Potassium - Dissolution - Leaching

摘要：Syenite is mainly composed of potassium feldspar (Kfs), which is a structural K-bearing mineral in soil, typically considered as an insoluble K resource. In contrast to the slow dissolution process, the initial non-steady state stage usually gives a fast K+ release rate and quickly decreasing, which is closely related with surface reactions. This process in a flow reactor has not been fully understood with a kinetic model. Earlier research about albite found that ion exchange and surface cation desorption occur rapidly, which leads to experimental efforts of this work. The 140-mesh (105-mm) and 325-mesh (44-mm) syenite leaching tests were performed under room temperature and pressure, using pH 1 and 3 diluted nitric acids, and flow rates from 0.01 to 1 mL min(-1) in a packed-bed flow reactor. Inductively coupled plasma mass spectrometry was used to measure the ions' (K+, Na+, Al3+, Si4+, Ca2+, Fe3+, Ba2(+)) time-dependent concentrations simultaneously. The pH measurement was added to monitor the consumption of reactant H+, providing reactant information crucial for understanding the surface reactions. The two fast surface reactions previously observed with albite were also observed with Kfs during the non-steady state. The initial K+ release kinetics were different from H+ adsorption and other surface atoms detachment. The slow dissolution reaction and the influence of transport factors were also evaluated. A model has been built with two parts that include the fast reactions and the transport-dissolution terms, conforming to the first-order equation with a leachant pH correction factor and a parabolic diffusion equation.