Effects of the activator on potassium release from potassium-rich shale and potassium feldspar and its mechanism

Objective Comprehensive utilization of water-insoluble potassium resources is helpful to relieve the contradiction between supply and demand of potash market.

Method The activated effects and fertilizer effects were studied by water extraction experiment and pot trial. The mechanism of activation was discussed by X-ray diffraction (XRD).

Result and conclusion The results of water extraction experiment indicated that, within the QN ratio of 0.1%-10.0%, potassium-rich shale and potassium feldspar had different activated effects. With the increase of QN ratio, the water-soluble K extraction from potassium-rich shale increased and then decreased, and the activated ratio of 1.0% was the best. For potassium feldspar, the water-soluble K accumulative amount increased as the ratio of QN increased, and when the QN ratio was 10.0%, the accumulation of water-soluble K was the highest. The pot trail results showed that the pot biomass of activated K-shale was 49.42% higher than that of K-shale, reaching the potassium chloride level. For activated K-feldspar, the corn biomass was not significantly different from K-feldspar, which was lower than that of K-chloride and activated K-shale. The results of XRD analysis indicated that, the mechanism of QN activated potassium-rich shale and potassium feldspar was an ion exchange reaction between Na⁺ and K⁺. Some new sodium minerals can be found in activated K-shale and activated K-feldspar. In activated K-shale, the new sodium minerals include K_0.96Na_0.04AlSi₃O₈, Na₄Al₂Si₆O₁₇·2H₂O and Na₆PbO₄, but it is Na₃Mn(PO₄)(CO₃) in activated K-feldspar.