The Recycling Theory And Technological Exploration Of Spent Diamond Tools In Ammonia Leaching Process

With the rapid development of economy and society,at the same time the consumption of copper and zinc were growing rapidly,the demand for copper and zinc were becoming more and more difficult to be satisfied.In addition,as the copper and zinc resources were decreasing,the amount of concentrate was reducing continually,while the lean ore taste was relatively so low that it was difficult to be treated.Therefore,it is of great significance to find a feasible way to recycle the copper and zinc resources.The spent diamond tools contained a certain amount of copper and zinc,which was a kind of potential secondary resources.If these waste materials were not recycled comprehensively,not only would the environment be polluted,but also a huge waste of resources would appear.For this reason,to recover the copper and zinc in the spent diamond tools effectively and utilized separately was of grate practical significance,which was also helpful to the environmental protection,the sufficient resources utilization and the sustainable development of society.In the present dissertation,the spent diamond tool was chosen as the raw material.The content of copper in the material was 29.16%,the zinc was 28.71% and the ferrum was 13.27%.In the leaching process of ammonia system,the selective dissolution was obtained among Cu,Zn and Fe,so that the preliminary separation of copper and zinc from alloy was achieved and it showed a promising short process for spent diamond tools recycle.According to systematic experimental study,the conclusions which were made were as follows:?1?The exterior of the spent diamond tool was like a cuboid block,the surface of the tool that close to the matrix was jagged,and the cutting surface was smooth.While the matrix was doped with diamond particles,which made the tools so hard and difficult to be broken.By means of XRD and SEM analysis,the Cu,Zn,Fe and other elements mainly existed in the form of elementary substance or oxides in the spent diamond tools.What's more,the structure was so compact that it was difficult to be dissociated,which was not favorable for separation and fragmentation.?2?Through the thermodynamic analysis of the ammonia leaching process,the main reactions that occurred during the leaching process was determined so that the transforming relationship was ascertained as well.?3?In the NH₃·H₂O-?NH₄?₂SO₄ leaching system,the tests were conducted and the results indicated that copper and zinc leaching rates were 64.67% and 68.16% respectively under the conditions of 45?,3.0h leaching time,50:1?ml/g?liquid–solid ratio,3.0mol/L ammonia,1.0mol/L ammonium sulfate,0.2L/min air velocity and 200r/min stirring speed.Good leaching effects were obtained.?4?By the exploring process of single factor cycling test,the optimum operating parameters of the tests conducted in the NH₃·H₂O-?NH₄?₂CO₃-H₂O₂ leaching system were as follows: the leaching temperature was 25?,leaching time was 2.5h,liquid-solid ratio was 40:1?ml/g?,the ammonia concentration was 3.0mol/L,the concentration of Ammonium carbonate was 1.0mol/L,the volume of hydrogen peroxide was 24 mL,the stirring speed was 300r/min.Under these conditions,the copper and zinc leaching rate in the materials reached 55.23% and 51.46% respectively,the leaching effect was well.?5?Through the ways of Cyclic Voltammetry and controlling the parameters in the electrolysis process,the leaching process in ammonia system could be strengthened by means of electrolysis,the effect of electrolyzing voltage on the leaching rate during the electrolysis process was explored under the conditions of the optimum parameters in the conventional leaching process.And according to which the optimum electrolyzing voltage was determined;The leaching rate of two kinds of metals in electrolytic condition was greatly improved,and the effect was obvious.What's more,the effect of different ammonium salts on the copper and zinc leaching rate during the electrolytic process was explored.Thus the better ammonium salt system in the electrolytic leaching process was achieved.The target of the exploratory tests above was to provide a theoretical basis for comprehensive treatment and recycling of spent diamond tools.At the same time,the effective separation of partial metals was obtained according to the properties of copper and zinc in the ammonia leaching solution.This method could pave the way for the subsequent recovery process of spent diamond tools materials and be helpful to the further processing.All of these leaching processes were good for the comprehensive recovery of secondary resources and environmental protection,and had important practical significance for the sustainable development of economic society as well.