Cogrinding Muscovite With Alkaline Metal Salts To Prepare Potassium-silicon Fertilizer And Heavy Metal Immobilizing Agent

Mica minerals are a general term for a class of typical potassium-rich layered silicate minerals.Muscovite is the most common and productive mica,which contains the highest potassium content.The excessive crushing of mica in the production and processing process generates a large number of abandoned broken mica.Therefore,recycling of these broken mica tailings is of great significance for a full use of mica resources.This study uses actual broken mica mines as raw materials.Through the process of mechanochemical activation and adding an alkaline metal salt as an activator,the dissolution rate of potassium and silicon are improved to serve as citric-soluble compound fertilizer.At the same time,the prepared samples have the function of fixing heavy metal ions.The main research contents are as follows:Mechanical forces activated single muscovite mineral.The experimental results showed that the mechanical force activation can destroy the structure of the muscovite sample.With the increase of the ball milling strength,the structure was gradually destroyed.At 300 rpm,the muscovite crystal structure changed from the original Muscovite-2M1 to Muscovite-1M.At this time,the slight destroy in structure was favorable for the dissolution of potassium in water.With the further increase of the rotation speed,the agglomeration of the sample particles hindered the water solubility of potassium.In 2% citric acid,the destruction of the muscovite structure greatly improved the solubility of potassium silicon,and the dissolution rates reached 81.39%and 16.06% under 600 rpm activation conditions,respectively.Adding alkaline metal salts as activators enhanced the dissolution of potassium and silicon.Calcium and magnesium salts were added as activators for co-milling activation.The test results showed that under the action of mechanical ball milling,the addition of calcium chloride and magnesium sulfate successfully achieved the ion exchange of Ca/K and Mg/K,thereby improving the water solubility of potassium.As the addition of calcium chloride and magnesium sulfate increased,in mixed grinding samples with Ca/K and Mg/K at 2/1,the proportion of water-soluble potassium was increased to 71.4% and 60.72%,respectively.At the same time,the addition of calcium and magnesium elements made the silicon in the sample with higher reactivity,so that the dissolution rate of citrus-soluble silicon was also increased to 47.33% and 46.54%,respectively.The activated samples with magnesium sulfate were used to fix heavy metal ions for soil remediation.For the cadmium ion solution,single-factor experiments were performed with several parameters examined: the amount of magnesium sulfate added,temperature,dosage,and initial p H.The test results showed that the fixation of cadmium ions by the sample mainly depended on the spontaneous exchange of fixed magnesium ions and cadmium ions.The mixed milled sample with Mg/K of 2/1 can reach removal rate of 87.79% for 100 m L of 100 mg/L Cd(Ⅱ)solution at an initial p H of 6 and a dosage of 5g/L.The removal rate increaseed with increasing temperature,and the removal rate of various heavy metal ions can still be maintained in a mixed heavy metal ion solution.This article starts from the treatment process to activate muscovite by mechanochemical method,and successfully increases the dissolution rate of potassium and silicon by adding alkaline metal salts as activators and the prepared sample has a good fixing effect on heavy metal ions.The processing technology is simple and efficient,and the production process is green and pollution-free,which is of great significance to the full use of broken muscovite resources.