Study On The Synthesis, Surface Dissolution Of Scheelite, Calcite, Fluorite And Their Absorption Capacities Of Reagent

With the decrease of wolframite resource in China,the scheelite has accounted to more than 70% in total wolfram resource,thus the effective development and utilization of scheelite have become important topics within mineral separation field.As a common selection method,flotation method has the problem that the floatability of scheelite,gangue and fluorite with calcium,and calcite etc are similar,and it would be hard to gain a higher index for mineral separation.As a result,it is important to intensify the research for basic theory for scheelite floatation separation.Given the complex component of actual mineral and boundedness of research results,the thesis conducts research by using the adsorbability for agent and dissolution of surface of synthetic mineral,and the results are as follows:(1)Using a chemical co-precipitation method,the scheelite,calcite and fluorite were synthesized by adjusting the outer factors such as temperature,pH,concentration,reaction time and etc.It was found that: while synthesizing scheelite,increasing concentration and pH can gain product with bigger granular,and the temperature can influence the feature of product;While synthesizing calcium carbonate,increasing concentration,pH and decreasing temperature can facilitate the forming of calcite,otherwise will form product with aragonite or nepheline structure;While synthesizing fluorite,increasing the concentration can broaden the grain size of product,and increase temperature can also change the feature of product.In addition,The growth mechanism of minerals,crystal structure and surface properties were analyzed and it was indicated that Man-made mineral was similar to the natural mineral in their properties and flotation behaviors.(2)By the test of surface dissolution of minerals and the chemical analysis of flotation solution,it was found that the chemical reaction occurred between scheelite,calcite,fluorite and the anion in solution,causing inconsistent dissolution behaviors of the ions on the minerals,which also resulted in fragmental particles on the surface of dissolved minerals,changing the morphology and chemical compositions of the minerals,affecting the effect of the separating floatation.The dissolved content of Ca2+ from the three kinds of minerals changed with the habitats: calcite> Fluorite> scheelite.This result also proved that the surface dissolution of scheelite,calcite and fluorite were associated greatly with their floatability.(3)Ultraviolet specrophotometer was used to study the absorption of several collecting agents on the surface scheelite,calcite and fluorite.It was found that the sodium oleate maintained a larger value in the surface of minerals adsorption capacity when the solution pH was in the range of 8-9,and it closed to Langmuir type linear equations to achieve monolayer absorption;When the solution pH was in the range of 8-9,the BHA had a larger amount of surface absorption on scheelite,calcite and fluorite,it was closer to BET type linear equations,the saturated absorption capacity value became larger with increasing concentration.And when lauryl amine in solution pH values was less than 10,the amount of surface absorption capacity of minerals went up with increasing pH value,and the absorption was closer to Freundlich type linear equations,which was in line with the twostep absorption theory.Moreover,adopting infrared spectroscopic analysis and electrokinetic potential testing to verify that the sodium oleates are surface chemisorptions for the above three minerals,and benzohydroxamic acid and lauryl amine are surface chemisorptions for scheelite and calcite,while are surface physical absorptions for fluorite.