Effects Of Microcrystailine Grinding On Potassium Release In Silicate Potassium Rocks And Its Application

Application of the insoluble potassium ore have stimulated plant growth, improved soilnutrients content and positively affected acidic soil properties. However, compared to theconventional potassium fertilizers, crushed or ground insoluble potassium rocks exhibit amuch slower potassium release and the effectiveness is relatively lower and a large amount ofmaterials have to be applied to meet crop needs. The use of insoluble potassium rocks inagriculture practices is very limited. Therefore the method of promoting the mineral elementsrelease became a crucial factor in utilizing the insoluble potassium resources. In this study,the K-feldspar rocks and muscovite rocks activated by a microcrystalline mill were used tostudy their physical-chemical properties and dissolution kinetics of mineral elements. Also,sand culture and soil culture experiment were carried to investigate the influence of activatedinsoluble potassium rocks on the growth of grain amaranth as well as on soil properties. Theresults were as follows:1. Microcrystalline grinding improved the physical properties of the insoluble potassiumrocks for a certain time. It appeared that mall particle size, high specific surface areas, roughsurface morphology and substantial structural disordering. When grinding under the samegrinding conditions, these favorable changes of K-feldspar powders are stronger thanmuscovite powders.2. Microcrystalline grinding promoted the dissolution of mineral elements from theinsoluble potassium rocks. With increasing gringding time, the single release of potassium,sodium, silicon, aluminum, calcium, magnesium and iron were significantly increased mostlydue to the changes of the physical properties and the maximum single release was obtained bykeeping the grinding time at120minutes. In comparison to the K-feldspar rocks, the mineralelements release except sodium in muscovite rocks were higher than the corresponding K-feldspar rocks.3. The leaching experiment results showed that microcrystalline grinding promoted theaccumulation of potassium in insoluble potassium rocks. Compared to the rude rocks, thepotassium release of the K-feldspar rocks and the muscovite rocks milled at120minuteswere significantly increased by7.14times and3.44times, respectively. In comparison withthe K-feldspar rocks, the potassium release of the muscovite rocks was significant higher.Judging from the potassium leaching rate, the K-feldspar rocks and the muscovite rocks milled at120minutes were7.50%and15.21%, respectively. This indicated that most of thepotassium was still inherent in the lattice bondage. To analyze by using gray relationalgrade, effective specific surface area was a key factor in the decision to potassium releasefrom potassium rocks.4. Sand culture experiment results showed that microcrystalline grinding improved thebioavailability of the insoluble potassium rocks. Compared with non-potassium nutrientsolution treatment, the use of the insoluble potassium rocks promoted plant growth andnutrients absorption, and with the extension of the milling time, the above trend was moreobvious. Under the same processing conditions, the bioavailability of muscovite rocks washighter than K-feldspar rocks. In comparison with full potassium nutrient solution treatment,the bioavailability of the insoluble potassium rocks was lower.5. Pot culture experiment results showed that application of potassium promoted plantgrowth, nutrients absorption and utilization, but also enhance the quality of grain amaranth.Among the potassium treatments, the result of activated potassium rocks was better than theordinary potassium rocks, and the effect of the muscovite rocks was highter than thecorresponding K-feldspar rocks. When increasing the amount of potassium rocks or combinedapplication of potassium rocks and potassium chloride, the promotive effect was better.Therefore, rational application of potassium rocks could promote the growth of plant andthese were of the constructive significance for relieving the potassium crisis.6. Pot culture experiment results also showed that application of potassium rocksincreased the soil potassium and improved the value of soil electrical conductivity and soilpH, which were of the positive significance for the soil potassium maintenance and acidic soilimprovement. In general, the result of activated potassium rocks was better than the ordinarypotassium rocks, and increasing the amount of potassium rocks or combined application ofpotassium rocks and potassium chloride was found to be much better than the others,especially increasing potassium rocks exhibited in soil improvement. It is an urgentlyquestion that how to scientifically apply potassium rocks and potassium chloride according toa certain proportion, which not only suiting crops growth but to solving water-solublepotassium leaching and soil acidification.