Study On Potassium Mineral Transformation And Potassium Reduction Of Molybdenum Concentrate During Roasting Process

Molybdenum and its compounds are widely used.Molybdenum resources are low in the world,molybdenite is the main source of molybdenum products.Molybdenite is mainly composed of Mo S₂.Mo S₂ is oxidized and roasted in multi-bore furnace to form Mo O₂,Mo O₃ and other oxides.Then ammonium molybdate can be obtained by ammonia leaching.Ammonium molybdate is a raw material for many molybdenum products.The impurity content,especially potassium content,determines the quality and purity of subsequent molybdenum products.Therefore,removing impurity potassium as much as possible in ammonium molybdate production process is the key measure to produce low potassium and low potassium molybdenum products.In the past,the effect of removing potassium impurity by acid leaching method is very good,but because of its long process,large amount of water treatment,and acidic wastewater needs to be treated to discharge,which is very harmful to the environment.At present,due to the environmental protection policy pickling has been completely prohibited,the water washing of molybdenum calcine is the main means of removing potassium.Therefore,it is very important to study the morphology and soluble changes of potassium in the process of molybdenum concentrate treatment,which can help enterprises to take reasonable measures to transform potassium-bearing minerals insoluble in water into soluble potassium ions and then be washed away by water,which has important theoretical significance for the production of low potassium molybdenum products.The raw material used in this experiment is a molybdenum concentrate provided by a molybdenum company in Shaanxi Province.The main component of the ore is Mo S2.Based on the analysis of the transformation of potassium-bearing minerals and the mechanism of potassium release during roasting,washing and ammonia leaching of molybdenum concentrate,some potassium reduction schemes are tried.The following conclusions are drawn from the experimental study:（1）In the roasting process of molybdenum concentrate,the main potassium minerals in molybdenum concentrate are feldspar,mica,barium iron mica and illite.The influence order of potassium minerals in molybdenum concentrate on potassium in ammonium molybdate products is:feldspar>mica>barium iron mica>illite.After washing,most of the soluble potassium enters the washing solution.In the process of ammonia leaching,ammonia solution can promote the release of potassium from feldspar and mica,so that some potassium elements enter the ammonia solution,resulting in the increase of potassium content in molybdenum products.（2）Potassium-containing minerals such as mica and syenite are insoluble or insoluble in water,and the solubility of potassium in these insoluble potassium-containing minerals increases in ammonia or acidic conditions.In the process of water washing or ammonia leaching,the release potassium will increase with the extension of washing or ammonia leaching time.Reducing the content of mica and feldspar in molybdenum concentrate is an effective potassium reduction method.（3）Through the screening of molybdenum concentrate,the existence of potassium is mainly concentrated in the molybdenum concentrate with the content of potassium above 200 meshes,which is higher than that of less than 200 meshes.According to the classification of molybdenum concentrate according to particle size,molybdenum concentrate with low potassium content and molybdenum concentrate with high potassium content can be screened out,so as to obtain molybdenum products with lower potassium content.Molybdenum calcine with different potassium contents can also be separated by grading the screening particle size of molybdenum calcine,so as to obtain molybdenum products with lower potassium content.