Role of Processing Temperature and Time on the Hydrothermal Alteration of K-Feldspar Rock in Autoclave
Abstract Potassium fertilizers (potash) are mined in a handful of countries in the Northern Hemisphere. Potash is either expensive or unavailable to the farmers of the Southern Hemisphere. Alkaline alteration of K-feldspar rock (ultrapotassic syenite) in autoclave in the presence of Ca2+ generates...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Springer International Publishing
2021
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| Online Access: | https://hdl.handle.net/1721.1/131490 |
| _version_ | 1826191169539801088 |
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| author | Ciceri, Davide de Oliveira, Marcelo Chen, Dennis P Allanore, Antoine |
| author_facet | Ciceri, Davide de Oliveira, Marcelo Chen, Dennis P Allanore, Antoine |
| author_sort | Ciceri, Davide |
| collection | MIT |
| description | Abstract
Potassium fertilizers (potash) are mined in a handful of countries in the Northern Hemisphere. Potash is either expensive or unavailable to the farmers of the Southern Hemisphere. Alkaline alteration of K-feldspar rock (ultrapotassic syenite) in autoclave in the presence of Ca2+ generates a mixture of K-bearing calcium-aluminum-silicate-hydrate (C-A-S-H) minerals that potentially can be used as an alternative local fertilizer. This work investigates the effect of processing temperature (200 °C, 220 °C, and 230 °C) and time (from 0.5 to 3.0 h) on pH, mineralogy, and elemental availability of the C-A-S-H mineral mixture. Increasing temperature results in an increased conversion of K-feldspar and increased content of both the mineral tobermorite (Ca5Si6O16(OH)2·4H2O) and amorphous phase in the resulting C-A-S-H mixture; increasing time results in an increased conversion of α-dicalcium silicate hydrate into tobermorite. The amount of K leached from the mixture is relatively constant across all processing conditions. Hydrothermal alteration in autoclave of K-feldspar-bearing rocks such as ultrapotassic syenite permits the synthesis of a potential potassium fertilizer which alkalinity and mineralogy can be tailored according to soil requirements. |
| first_indexed | 2024-09-23T08:51:23Z |
| format | Article |
| id | mit-1721.1/131490 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T08:51:23Z |
| publishDate | 2021 |
| publisher | Springer International Publishing |
| record_format | dspace |
| spelling | mit-1721.1/1314902021-09-21T04:02:22Z Role of Processing Temperature and Time on the Hydrothermal Alteration of K-Feldspar Rock in Autoclave Ciceri, Davide de Oliveira, Marcelo Chen, Dennis P Allanore, Antoine Abstract Potassium fertilizers (potash) are mined in a handful of countries in the Northern Hemisphere. Potash is either expensive or unavailable to the farmers of the Southern Hemisphere. Alkaline alteration of K-feldspar rock (ultrapotassic syenite) in autoclave in the presence of Ca2+ generates a mixture of K-bearing calcium-aluminum-silicate-hydrate (C-A-S-H) minerals that potentially can be used as an alternative local fertilizer. This work investigates the effect of processing temperature (200 °C, 220 °C, and 230 °C) and time (from 0.5 to 3.0 h) on pH, mineralogy, and elemental availability of the C-A-S-H mineral mixture. Increasing temperature results in an increased conversion of K-feldspar and increased content of both the mineral tobermorite (Ca5Si6O16(OH)2·4H2O) and amorphous phase in the resulting C-A-S-H mixture; increasing time results in an increased conversion of α-dicalcium silicate hydrate into tobermorite. The amount of K leached from the mixture is relatively constant across all processing conditions. Hydrothermal alteration in autoclave of K-feldspar-bearing rocks such as ultrapotassic syenite permits the synthesis of a potential potassium fertilizer which alkalinity and mineralogy can be tailored according to soil requirements. 2021-09-20T17:17:18Z 2021-09-20T17:17:18Z 2020-05-22 2020-09-24T21:20:37Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/131490 en https://doi.org/10.1007/s42461-020-00233-6 Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ Society for Mining, Metallurgy & Exploration Inc. application/pdf Springer International Publishing Springer International Publishing |
| spellingShingle | Ciceri, Davide de Oliveira, Marcelo Chen, Dennis P Allanore, Antoine Role of Processing Temperature and Time on the Hydrothermal Alteration of K-Feldspar Rock in Autoclave |
| title | Role of Processing Temperature and Time on the Hydrothermal Alteration of K-Feldspar Rock in Autoclave |
| title_full | Role of Processing Temperature and Time on the Hydrothermal Alteration of K-Feldspar Rock in Autoclave |
| title_fullStr | Role of Processing Temperature and Time on the Hydrothermal Alteration of K-Feldspar Rock in Autoclave |
| title_full_unstemmed | Role of Processing Temperature and Time on the Hydrothermal Alteration of K-Feldspar Rock in Autoclave |
| title_short | Role of Processing Temperature and Time on the Hydrothermal Alteration of K-Feldspar Rock in Autoclave |
| title_sort | role of processing temperature and time on the hydrothermal alteration of k feldspar rock in autoclave |
| url | https://hdl.handle.net/1721.1/131490 |
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