Sedimentary Cobalt Manganese Ore Dressing And Smelting Process And Mechanism Studies

Cobalt plays a significant role in the development of national economy. As cobalt has a property of strong migration,90%of cobalt appears in dispersion state in the crust. At the same time, the cobalt has thiophilic and siderophile affinities, so most is generated with associated metal and a few independent or cobalt-based industrial ore deposits are formed. China is one of the countries lacking cobalt resources. Hanyuan cobalt-manganese ore (The Jiaodingshan mountain cobalt-manganese ore) is located in the north of the Hanyuan County in the south of Sichuan province, and this mineral deposit is a "high quality manganese-rich deposit", which is an important production base of manganese ore in Sichuan province.Hanyuan cobalt-manganese ore belongs to typical chemical depositional cobaltiferous rhodochrosite ore. Since cobalt ores are mainly distributed in the interlayer of rocks, and the ore bed is rather thin, they can only be mined with manganese ore. Cobalt-manganese ore is present in the form of uneven distributed dissenminated ore, which leads that the separation is difficult. Although cobalt is predominately present in siegenite, and manganese in rhodochrosite, only manganese is recovered for a long time, and cobalt is not recovered as it is difficult to separate cobalt. This results in serious waste of cobalt resources.For Hanyuan depositional manganese cobalt, a new and effective metallurgical process of "flotation-high intensity magnetic separation-chlorinated segregation-low intensity magnetic separation" is proposed in this study based on the study of process mineralogy of ore and relevant experiments. Meanwhile, an ideal technology index is obtained through the testwork, and comprehensive recovery of manganese and cobalt is realized. The new technology will have an important instructive significance for the development and utilization of cobalt-manganese, especially for the recovery of cobalt.First, a large number of minerals mineralogical studies have been conducted, and the results indicate that the crude ore with cobalt grade of0.23%, manganese grade of10.52%, nickel gradeof0.29%belongs to polymetallic ore which predominately appears as cobalt and manganese. Cobalt exists in the ore mainly in the form of siegenite and cobaltite, but most of cobalt is outputted in the form of solid solution together with pyrite, which is present as fine disseminated granularity, part of the granularity to2microns. It demonstrates the phenomenon of mutual symbiosis and serious mutual package.10.43%of cobalt minerals are distributed in rhodochrosite, dolomite, calcite, etc and in a form ofsuper-fine granularity. Manganese is mainly present as rhodochrosite, with disseminated granularity from0.005mm to0.1mm. Although cobalt and manganese are present independently in the depositional cobalt-manganese ore, it is difficult to recover cobalt and manganese due to such factors as fine disseminated granularity, output form of solid solution, serious mutual packaging, dissemination etc.On the basis of mineralogical study, the tests and studies on separation cobalt and manganese for the enrichment of cobalt have been performed. test results show that the method of high intensity magnetic separation can achieve great separation effect for manganese, and the method of gravity separation can improve the grade of cobalt, but ideal cobalt and manganese separation index can not obtained through both methods. Therefore, the testwork of flotation for pre-enrichment cobalt is conducted. The process flow of rough floating for one time and scavenging for two times is worked out through lots of tests under flotation process conditions, through which cobalt appears in the grade of0.84%with separation index of87.64%. It adopts high intensity magnetic separation process of roughing for one time and handpicking for one time to recover test flowsheet of to manganese from flotation tailings. The manganese separation index shows that manganese is in the grade of30.12with recovery rate of72.37%. In a word, it comes to the conclusion that it is difficult to further improve cobalt grade and the recovery rate through physical separation methods through such analysis as cobalt concentrate flotation of XRD diffraction analysis, sulfur content phase analysis, arsenic object is analysis and chemical composition analysis.In order to further improve the cobalt separation indexes, the tests of cobalt separation from flotation cobalt ore concentrate have been carried out through the method of sulfating roasting-leaching. The test results indicate that the impurities like CaO, MgO, SiO2, Al2O3are relatively high and cobalt minerals are present with the following embedded characters such as low leaching rate, large consumption of acid, and the difficulty of solid-liquid separation. These lead that, under such comprehensive process conditions as roasting temperature of600℃, roasting time of3h, leaching liquid-solid ratio of L/S=3, leaching time of3h, and leaching pH=1, cobalt leaching rate is only71.05%, and desulphurization rate is82.86%. Therefore, sulfating roasting-leaching separation cobalt is not workable.As sulfated roasting-leaching separation cobalt index is quite poor, the method of chlorinated segregation-low intensity magnetic separation mineralogical reconstruction is employed for further research of the separation of cobalt. In the process of chlorinated segregation, hematite is fed as activator for cobalt segregation. Meanwhile, thermodynamic analysis results have verified the activation function of hematite. Lime is used for adjustment the degree of silicate for separated materials, which promotes the reaction while making sulfur and arsenic fixed. Sulfur is mainly transformed into sulfate and arsenic mainly into arsenate during the process. The application of cuprous chloride as a catalyst can shorten the segregation time from75min to45min. Under the following conditions: segregation temperature of1100℃, segregation time of45min, coke dosage of7%, coke granularity of-0.5+0mm, calcium chloride dosage of11%, silicate degree of R4=0.70, hematite dosage of (including iron66.78%) of5%, cuprous chloride dosage of1%, and90%of-0.045mm grinding fineness, segregation cobalt concentrate separation indexes are obtained by cobalt separation process of chlorination separation-low intensity magnetic separation with magnetic separation degree of H=0.15T. The indexes appear that the outputted cobalt is in grade of4.18%with work recovery rate of96.14%. Preliminary recycled tests have been performed for the tail gas with main ingredient of hydrogen chloride gas which is produced in the process of chlorinated segregation. Test results indicate that:the recovery efficiency of Cl-is up to75.27%when limewater is employed to absorb tail gas; and regenerated calcium chloride can be recycled and used as as chlorinated agent; meanwhile, the obtained index of cobalt segregation is ideal.In order to survey beneficiation indexes of overall combined technique of processing and metallurgy for cobalt and manganese, tests have been conducted for the whole process of flotation-Strong magnetic separation-chlorination separation-low intensity magnetic separation. Based on previously achieved comprehensive process parameters, it comes to the results as follows:cobalt grade of4.18%, contained nickel of1.92%, and cobalt concentrate with cobalt recovery rate of82.64%; manganese grade of30.12%, contained nickel of0.18%, and manganese concentrate with manganese recovery rate of72.42%. Through the tests, the comprehensive utilization of cobalt and manganese has been realized for Hanyuan depositional cobalt-manganese ore.To find out the evolution mechanism of cobalt concentrate in the process of chlorination segregation and mineralogical roasting reconstruction, mineralogical phase of SEM and composition of EMPA analyses have been separately processed for flotated cobalt concentrate and segregated products. The results indicate that cobalt mineralogical phase, as linnaeite (siegenite and cobaltite) has been transformed into a new cobalt mineralogical phase——"cobaltiferous iron ore" which is predominately present as cobalt, nickel and iron. Under the current theory of generation of new phase, chlorinated segregation metallurgical kinetic model and conclusion of relevant analyses and researches,"gas-solid phased particles structure change model" has been proposed in the process of chlorination segregation and reconstruction of Mineralogical Phase, and mathiematical analyses also have been conducted for the dynamic model. It reaches a conclusion, based on the results, that iron, cobalt and nickel are mainly present as metal particles during the process of chloride segregation; finally new mineralogical phase of "cobaltiferous iron ore" has been formed actually due to the changes of solid particles structure; meanwhile, part of mineralogical phase of "cobalt pyrite" has been formed.In this thesis, testwork has been performed together with mechanism research for Hanyuan depositional cobalt-manganese ore by "the new combined technique of processing and metallurgy of "flotation-high intensity magnetic separation-chlorinated segregation-low intensity magnetic separation". The greatest achievement is that cobalt concentrate ore has been produced with cobalt grade of4.18%and cobalt comprehensive recovery of86.24%.This breaks the current situation that only manganese is recover, and establises an important test foundation and theoretical basis for comprehensive utilization of Hanyuan sedimentary cobalt-manganese ore.