Author Contributions
Methodology, X.Z., Z.H. (Zhenquan He), W.J. and F.M.; Data curation, X.Z. and Z.H. (Zhenquan He); Writing original draft, X.Z.; Funding, X.Z., G.G. and Z.H. (Zhenquan He); Resources, Validation, W.J., X.H. and K.W.; Project administration, F.M. and W.Z.; Supervision, Z.H. (Zhaohui Huang) and C.L.; Writing—review, W.Z., C.L., M.X. and S.Y.; Conceptualization, G.G., Z.H. (Zhaohui Huang) and S.Y. All authors have read and agreed to the published version of the manuscript.
Figure 1.
Experimental design sketch.
Figure 1.
Experimental design sketch.
Figure 2.
Changes in particle size (D50, D97) of potassium feldspar in presence of additives during grinding. (a) D50 in presence of no additive, 5% NaOH and 10% NaOH, (b) D97 in presence of no additive, 5% NaOH and 10% NaOH, (c) D50 and D97 in presence of 5% NaCl, (d) D50 and D97 in presence of 5% Na2CO3, (e) D50 and D97 in presence of 5%Na2SO4.
Figure 2.
Changes in particle size (D50, D97) of potassium feldspar in presence of additives during grinding. (a) D50 in presence of no additive, 5% NaOH and 10% NaOH, (b) D97 in presence of no additive, 5% NaOH and 10% NaOH, (c) D50 and D97 in presence of 5% NaCl, (d) D50 and D97 in presence of 5% Na2CO3, (e) D50 and D97 in presence of 5%Na2SO4.
Figure 3.
Change in the PSD of potassium feldspar in the presence of additives during grinding. Additives: (a) no additive, (b) 5% NaOH, (c) 10% NaOH, (d) 5%NaCl, (e) 5% Na2CO3, and (f) 5% Na2SO4.
Figure 3.
Change in the PSD of potassium feldspar in the presence of additives during grinding. Additives: (a) no additive, (b) 5% NaOH, (c) 10% NaOH, (d) 5%NaCl, (e) 5% Na2CO3, and (f) 5% Na2SO4.
Figure 4.
Changes in water-soluble potassium contents of feldspar in presence of NaOH and sodium salts under mechanical activation (reported values are statistically significant (p < 0.05)).
Figure 4.
Changes in water-soluble potassium contents of feldspar in presence of NaOH and sodium salts under mechanical activation (reported values are statistically significant (p < 0.05)).
Figure 5.
Potassium dissolved in pure water and NaOH solution during shaking: raw powder (PF1), raw powder + NaOH (5%) (PF2), ground feldspar for 180 min (PF3), and ground feldspar for 180 min + NaOH (5%) (PF4) (Reported values are statistically significant (p < 0.05)).
Figure 5.
Potassium dissolved in pure water and NaOH solution during shaking: raw powder (PF1), raw powder + NaOH (5%) (PF2), ground feldspar for 180 min (PF3), and ground feldspar for 180 min + NaOH (5%) (PF4) (Reported values are statistically significant (p < 0.05)).
Figure 6.
The changes in available potassium of feldspar in the presence of additives during grinding (reported values are statistically significant (p < 0.05)).
Figure 6.
The changes in available potassium of feldspar in the presence of additives during grinding (reported values are statistically significant (p < 0.05)).
Figure 7.
The changes in specific surface area as a function of grinding duration.
Figure 7.
The changes in specific surface area as a function of grinding duration.
Figure 8.
Changes in XRD diffraction peak intensities of potassium feldspar during grinding.
Figure 8.
Changes in XRD diffraction peak intensities of potassium feldspar during grinding.
Figure 9.
Changes in XRD diffraction peak intensities of potassium feldspar mechanically activated with 5% NaOH.
Figure 9.
Changes in XRD diffraction peak intensities of potassium feldspar mechanically activated with 5% NaOH.
Figure 10.
Particle morphologies of potassium feldspar powder at different grinding durations: (×1000) 15 min (a), 90 min (b), and 150 min (c), (×50,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 10.
Particle morphologies of potassium feldspar powder at different grinding durations: (×1000) 15 min (a), 90 min (b), and 150 min (c), (×50,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 11.
Particle morphology of potassium feldspar powder treated with 5% NaOH at different grinding times of: (×1000) 15 min (a), 90 min (b), 150 min (c), (×50,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 11.
Particle morphology of potassium feldspar powder treated with 5% NaOH at different grinding times of: (×1000) 15 min (a), 90 min (b), 150 min (c), (×50,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 12.
The particle morphologies of potassium feldspar powder treated with NaCl at different grinding durations: (×1000) 15 min (a), 90 min (b), 150 min (c), (×50,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 12.
The particle morphologies of potassium feldspar powder treated with NaCl at different grinding durations: (×1000) 15 min (a), 90 min (b), 150 min (c), (×50,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 13.
Particle morphologies of potassium feldspar powder treated with Na2CO3 for different grinding times: (×1000) 15 min (a), 90 min (b) 150 min (c), (×50,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 13.
Particle morphologies of potassium feldspar powder treated with Na2CO3 for different grinding times: (×1000) 15 min (a), 90 min (b) 150 min (c), (×50,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 14.
Particle morphologies of potassium feldspar activated by mechanical force with Na2SO4 for different grinding times of: (×500) 15 min (a), 90 min (b), 150 min (c), (×25,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 14.
Particle morphologies of potassium feldspar activated by mechanical force with Na2SO4 for different grinding times of: (×500) 15 min (a), 90 min (b), 150 min (c), (×25,000) 15 min (d), 90 min (e), and 150 min (f).
Figure 15.
Energy dispersive X-ray spectroscopy (EDS) images of potassium feldspar powder and their elemental compositions.
Figure 15.
Energy dispersive X-ray spectroscopy (EDS) images of potassium feldspar powder and their elemental compositions.
Table 1.
Total elements of potash feldspar powder.
Table 1.
Total elements of potash feldspar powder.
Element | Content (%) | Element | Content (%) | Element | Content (%) | Element | Content (%) |
---|
SiO2 | 67.03 | CaO | 1.44 | Rb2O | 0.0293 | S | 0.0139 |
Al2O3 | 18 | BaO | 0.633 | Cr2O3 | 0.0273 | Nd2O3 | 0.0040 |
K2O | 8.69 | MgO | 0.106 | Ag2O | 0.0113 | PbO | 0.0039 |
Na2O | 3.36 | P2O5 | 0.0708 | MnO | 0.0054 | Ga2O3 | 0.003 |
Fe2O3 | 0.359 | TiO2 | 0.0323 | NiO | 0.0024 | | |
SrO | 0.155 | Cl | 0.018 | ZnO | 0.0011 | | |
Table 2.
Fitting equations of water-soluble potassium of feldspar activated by mechanical force.
Table 2.
Fitting equations of water-soluble potassium of feldspar activated by mechanical force.
NaOH Addition | Fitting Equation | R2 | Fitting Equation Type |
---|
0% mass | y = 59.64 + 1.83x | 0.9431 | linear equation |
5% mass | y = 418.98(x − 0.01)0.23 | 0.9751 | power function equation |
10% mass | y = 808.25x0.23 | 0.9613 | power function equation |
Table 3.
Fitting equation of available potassium of feldspar activated by NaOH at various grinding durations.
Table 3.
Fitting equation of available potassium of feldspar activated by NaOH at various grinding durations.
NaOH Addition | Fitting Equation | R2 | Fitting Equation Type |
---|
0% mass | y = 391.07 + 12.06x | 0.9963 | linear equation |
5% mass | y = 435.48(x + 1.15)0.38 | 0.9837 | power function equation |
10% mass | y = 1112.69(x − 0.03)0.27 | 0.9810 | power function equation |
Table 4.
Changes in XRD diffraction intensities of potassium feldspar during grinding.
Table 4.
Changes in XRD diffraction intensities of potassium feldspar during grinding.
Time/min | The Diffraction Peak |
---|
Mineral | KAlSi3O8 | SiO2 | NaAlSi3O8 |
2θ | 26.64° | 27.54° | 28.00° |
Crystal plane | 220 | 011 | 002 |
0 | 14,546 | 51,322 | 23,928 |
15 | 11,950 | 15,713 | 10,404 |
90 | 9624 | 9858 | 6803 |
180 | 9211 | 8382 | 5794 |
300 | 7944 | 6273 | 4708 |
Table 5.
Changes in XRD diffraction intensities of feldspar treated with 5% NaOH during grinding.
Table 5.
Changes in XRD diffraction intensities of feldspar treated with 5% NaOH during grinding.
Time/min | Diffraction Peak Intensity |
---|
mineral | KAlSi3O8 | SiO2 | NaAlSi3O8 |
2θ | 26.64° | 27.54° | 28.00° |
Crystal plane | 220 | 011 | 002 |
0 | 14,546 | 51,322 | 23,928 |
15 | 11,864 | 15,479 | 9447 |
90 | 8975 | 9213 | 6105 |
180 | 9351 | 5712 | 4892 |
300 | 8233 | 5259 | 3998 |
Table 6.
XRD diffraction intensities of potassium feldspar treated with 5% NaOH, NaCl, and Na2CO3 during grinding.
Table 6.
XRD diffraction intensities of potassium feldspar treated with 5% NaOH, NaCl, and Na2CO3 during grinding.
Time/min | | The Diffraction Peak Intensity |
---|
Mineral | KAlSi3O8 | KAlSi3O8 | KAlSi3O8 | KAlSi3O8 |
Additives | | +NaOH | +NaCl | +Na2CO3 |
2θ | 26.64° | 26.64° | 26.64° | 26.64° |
crystal plane | 220 | 220 | 220 | 220 |
0 | 14,546 | 14,546 | 14,546 | 14,546 |
15 | 11,950 | 11,864 | 11,083 | 9207 |
90 | 9624 | 8975 | 9643 | 10,776 |
180 | 9211 | 9351 | 9943 | 8959 |
300 | 7944 | 8233 | 8329 | 7647 |