South Africa is a net importer of fertilizer products, importing all of its potassium, as well as 60–70% of its nitrogen requirements. Thus, domestic prices are impacted significantly by international prices, shipping costs, and exchange rates. Producing these fertilizers locally would be far more economical. Phlogopite, a rich source of potassium, is discarded in large quantities during mining operations; the objective of the present study, therefore, was to determine the acid-leaching characteristics and behavior of phlogopite as a means of releasing potassium. Phlogopite samples were leached with nitric acid (source of nitrogen for fertilizers) at various concentrations, temperatures, and reaction times. The feed phlogopite and leached residue samples corresponding to conversions of 14% (LP1), 44% (LP2), and 100% (LP3) were collected and analyzed using X-ray fluorescence spectroscopy (XRF), X-ray diffractometry (XRD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), Brunauer–Emmett–Teller surface area and porosity analysis (BET), thermogravimetric analysis (TGA), and field emission gun-scanning electron microscopy (FEG-SEM). The feed phlogopite was highly crystalline. The absence of defects in the lattice meant that the motion of H⁺ atoms penetrating into the lattice was restricted, suggesting internal diffusion-controlled leaching. Furthermore, results obtained from the various analytical techniques corroborated each other in terms of the release of cations during leaching. All leaching experiments were conducted batchwise, in a closed system. The gravimetric data from the experiments were used to identify a suitable model which predicts accurately the leaching behavior. The reaction was found to be internal diffusion-controlled, and the D1 model, which represents one-dimensional diffusion through a flat plate, predicts the leaching behavior most accurately. The observed activation energies (E_a) and pre-exponential constants (k₀) varied with initial nitric acid concentration ([H⁺]₀).

南非是化肥产品的净进口国，其所有的钾以及 60-70% 的氮需求均来自于进口。因此，国内价格受到国际价格、运输成本和汇率的显着影响。在当地生产这些肥料会更经济。金云母是钾的丰富来源，在采矿作业中被大量丢弃；因此，本研究的目的是确定金云母作为释放钾的一种手段的酸浸特性和行为。金云母样品用不同浓度、温度和反应时间的硝酸（肥料的氮源）浸出。进料金云母和浸出残渣样品对应转化率为 14% (LP1)、44% (LP2)、收集并使用 X 射线荧光光谱 (XRF)、X 射线衍射 (XRD)、衰减全反射-傅里叶变换红外光谱 (ATR-FTIR)、Brunauer-Emmett-Teller 表面积和分析 100% (LP3)孔隙率分析 (BET)、热重分析 (TGA) 和场发射枪扫描电子显微镜 (FEG-SEM)。进料金云母是高度结晶的。晶格中没有缺陷意味着 H 的运动⁺原子渗透到晶格中受到限制，表明内部扩散控制浸出。此外，从各种分析技术获得的结果在浸出过程中的阳离子释放方面相互印证。所有浸出实验均在封闭系统中分批进行。来自实验的重量数据用于确定准确预测浸出行为的合适模型。该反应被发现是内部扩散控制的，代表通过平板的一维扩散的 D1 模型最准确地预测了浸出行为。观察到的活化能 ( E _a ) 和指前常数 (k ₀ ) 随初始硝酸浓度 ([H⁺ ] ₀ )。