Scholarlink

<p>Illite, a prevalent clay mineral found in hydrated bauxite ore, decreases the aluminum-to-silicon ratio (Al &lt; 7) while inducing competitive crystallization between sodium and potassium during the leaching process, thereby reducing the leaching efficiency of aluminum oxide. Consequently, illite-type bauxite ores are typically subjected to desiliconization prior to undergoing Bayer process leaching. However, this conventional desiliconization exhibits limited efficacy in illite removal and requires further refinement. To overcome these limitations, this study proposes the ‘calcification-potassium alkali’(CPA) process, which substitutes KOH for NaOH in a simulated Bayer process targeting illite. This strategy alleviates sodium–potassium competition and facilitates the complete utilization of elements to synthesize potassium aluminosilicate. Furthermore, calcium oxide is partially incorporated to purify the mother liquor. Experimental investigations were conducted to evaluate leaching performance under varying conditions, leading to the determination of optimal parameters: a temperature of 280&#xa0;°C, a calcium-silicon ratio of 0.2, a liquid–solid ratio of 5:1, a K<sub>2</sub>O concentration of 200&#xa0;g/L, and a reaction duration of 60&#xa0;min. Under these conditions, the illite conversion rate reached 98.65%, with the effective K₂O and SiO<sub>2</sub> contents in the product measured at 21.73% and 27.17%, corresponding to 89.38% and 86.54% of the total K<sub>2</sub>O and SiO<sub>2</sub>, respectively. Moreover, these parameters satisfy the national standards for organic–inorganic compound fertilizers, enabling subsequent production of mineral potassium-silicon fertilizers. Further leaching experiments on illite-type hydrated bauxite demonstrated efficient aluminum extraction, achieving a leaching rate of 73.82%, while effecting a phase transformation of the aluminum–silicon mineral from hydrated sodium aluminum silicate (Na<sub>2</sub>O·Al<sub>2</sub>O<sub>3</sub>·1.7SiO<sub>2</sub>·nH<sub>2</sub>O), typical of the traditional Bayer process, to potassium aluminum silicate (K<sub>2</sub>O·Al<sub>2</sub>O<sub>3</sub>·SiO<sub>2</sub>). This transformation can be utilized to prepare mineral potassium silicate fertilizers, which supply essential nutrients to plants and promote environmentally sustainable practices within both metallurgical and agricultural industries.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Study on the synergistic preparation of mineral potassium silicate fertilizer by hydrothermal leaching of illite under the “Calcification-Potassium alkali” system

  • 期刊论文

  • 发表日期：

    2025年11月17日

查看全文
  • Qingdong Li,
  • Guozhi Lv,
  • Xin He,
  • Zhihui Gu,
  • Zhuangzhuang Yun,
  • Xiaolei Zhang,
  • Lingtao Hu,
  • Tingan Zhang

摘要

Illite, a prevalent clay mineral found in hydrated bauxite ore, decreases the aluminum-to-silicon ratio (Al < 7) while inducing competitive crystallization between sodium and potassium during the leaching process, thereby reducing the leaching efficiency of aluminum oxide. Consequently, illite-type bauxite ores are typically subjected to desiliconization prior to undergoing Bayer process leaching. However, this conventional desiliconization exhibits limited efficacy in illite removal and requires further refinement. To overcome these limitations, this study proposes the ‘calcification-potassium alkali’(CPA) process, which substitutes KOH for NaOH in a simulated Bayer process targeting illite. This strategy alleviates sodium–potassium competition and facilitates the complete utilization of elements to synthesize potassium aluminosilicate. Furthermore, calcium oxide is partially incorporated to purify the mother liquor. Experimental investigations were conducted to evaluate leaching performance under varying conditions, leading to the determination of optimal parameters: a temperature of 280 °C, a calcium-silicon ratio of 0.2, a liquid–solid ratio of 5:1, a K2O concentration of 200 g/L, and a reaction duration of 60 min. Under these conditions, the illite conversion rate reached 98.65%, with the effective K₂O and SiO2 contents in the product measured at 21.73% and 27.17%, corresponding to 89.38% and 86.54% of the total K2O and SiO2, respectively. Moreover, these parameters satisfy the national standards for organic–inorganic compound fertilizers, enabling subsequent production of mineral potassium-silicon fertilizers. Further leaching experiments on illite-type hydrated bauxite demonstrated efficient aluminum extraction, achieving a leaching rate of 73.82%, while effecting a phase transformation of the aluminum–silicon mineral from hydrated sodium aluminum silicate (Na2O·Al2O3·1.7SiO2·nH2O), typical of the traditional Bayer process, to potassium aluminum silicate (K2O·Al2O3·SiO2). This transformation can be utilized to prepare mineral potassium silicate fertilizers, which supply essential nutrients to plants and promote environmentally sustainable practices within both metallurgical and agricultural industries.