Microwave pyrolysis of walnut shell for reduction process of low-grade pyrolusite

Kangqiang Li; Guo Chen; Jin Chen; Jinhui Peng; Roger Ruan; C Srinivasakannan

doi:10.1016/j.biortech.2019.121838

Microwave pyrolysis of walnut shell for reduction process of low-grade pyrolusite

Bioresour Technol. 2019 Nov:291:121838. doi: 10.1016/j.biortech.2019.121838. Epub 2019 Jul 19.

Authors

Kangqiang Li¹, Guo Chen², Jin Chen³, Jinhui Peng⁴, Roger Ruan⁵, C Srinivasakannan⁶

Affiliations

¹ Key Laboratory of Unconventional Metallurgy, Ministry of Education, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, PR China.
² Key Laboratory of Unconventional Metallurgy, Ministry of Education, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, PR China; Key Laboratory of Green-Chemistry Materials in University of Yunnan Province, Yunnan Minzu University, Kunming 650500, Yunnan, PR China; Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, Central South University, Changsha 410083, Hunan, PR China.
³ Key Laboratory of Unconventional Metallurgy, Ministry of Education, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, PR China. Electronic address: jinchen@kmust.edu.cn.
⁴ Key Laboratory of Unconventional Metallurgy, Ministry of Education, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, PR China; Key Laboratory of Green-Chemistry Materials in University of Yunnan Province, Yunnan Minzu University, Kunming 650500, Yunnan, PR China.
⁵ Key Laboratory of Green-Chemistry Materials in University of Yunnan Province, Yunnan Minzu University, Kunming 650500, Yunnan, PR China; Center for Biorefining, Bioproducts and Biosystems Engineering Department, University of Minnesota, 1390 Eckles Ave., Saint Paul, MN 55108, USA.
⁶ Chemical Engineering Department, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.

PMID: 31344635
DOI: 10.1016/j.biortech.2019.121838

Abstract

Replacing fossil energy by utilizing biomass as carbon source to convert metal oxides has meaning for reduction of minerals. Microwave pyrolysis of walnut shell for reduction process of low-grade pyrolusite was proposed. Thermogravimetric analysis indicated biomass pyrolysis process for reduction of pyrolusite was divided into four phases identified by temperatures: dehydration stage (<150 °C), pre-pyrolysis stage (150 °C-290 °C), curing decomposition stage (290 °C-480 °C) and carbonization stage (>480 °C), and manganese recovery reached 92.01% at 650 °C for 30 min with 18% walnut shell. The strongest preferential orientation of MnO was appeared, with good crystalline structure and no MnO₂ and FeO peaks detected. The product surface became loose and porous with numerous cracks, pits and holes, and molten granules were interconnected and stacked with regular shape. The methods propose new idea of selective reduction of pyrolusite based on biomass pyrolysis by microwave heating.

Keywords: Biomass pyrolysis; Low-grade pyrolusite; Microwave heating; Phase transformation; Structural; Thermal behavior.

MeSH terms

Biomass
Carbon / chemistry
Hot Temperature
Juglans / chemistry*
Manganese Compounds / chemistry
Microwaves
Oxides / chemistry
Pyrolysis

Substances

Manganese Compounds
Oxides
Carbon
manganese dioxide