沉积型钴锰矿选冶新工艺及机理研究

【作者】 肖军辉；

【导师】 文书明；

【作者基本信息】 昆明理工大学 ， 矿物加工工程， 2012， 博士

【摘要】 钴作为一种重要的战略物资金属,在国民经济和社会经济发展中具有重要意义。由于钴具有较强的迁移能力,在地壳中90%呈分散状态。同时,钴具有亲硫亲铁双重性,所以多以伴生金属产出,很少形成独立的或以钻为主的工业矿床。中国也是钴资源缺乏的国家之一,汉源钴锰矿(轿顶山钴锰矿)地处四川南部的汉源县北部,该矿床是“优质富锰矿床”是四川省重要的锰矿石生产基地。汉源钴锰矿属于典型的化学沉积型含钻菱锰矿石,由于该钴矿石主要分布于岩石的夹层中,并且矿层较薄,只能与锰矿石混采,钴锰矿石为不均匀浸染状矿石,分选难度很大。虽然矿石中钴以硫镍钴矿为主,锰以菱锰矿为主,但是长期以来仅仅对锰进行回收,由于钴的分选难度较大,没有对钻进行回收利用,导致钴资源的严重浪费。本研究针对汉源沉积型钴锰在进行了大量的矿石工艺矿物学研究和试验研究工作的基础上,创造性地提出“浮选—强磁选—氯化离析—弱磁选”的高效选冶新工艺,并得到了理想的技术指标,实现了钴锰的综合回收。该选冶新工艺技术将对汉源钴锰的开发利用,尤其是对钴的回收具有重要的指导意义。首先,对矿石进行了大量的工艺矿物学研究,研究结果得出原矿含钴0.23%、含锰10.52%、含镍0.29%属于以钴锰为主的多金属矿石。矿石中钴主要以硫镍钴矿和辉砷钴形式存在,但大部分钴矿物与黄铁矿呈固溶体形式产出,嵌布粒度细,部分粒度细至2微米,相互共生,包裹现象严重；有10.43%的钴矿物分布于菱锰矿、白云石、方解石等脉石中且粒度很细。锰主要以菱锰矿形式产出,嵌布粒度为0.005～0.1mm。沉积型钴锰中虽然钴锰均以独立矿物存在,但由于嵌布粒度细、呈固溶体形式产出、互相包裹、浸染现象严重等因素,给钴锰综合回收带来了相当大的难度。在矿石工艺矿物学研究的基础上,进行了钴锰分选富集钻试验研究。试验结果表明,强磁选对锰能实现较好的分选效果,重选能够提高钻的品位,但均存在不能得到理想钴锰分选指标的问题。为此,进行了浮选预先富集钴试验,通过大量的浮选工艺条件试验得出一次粗选两次扫选的浮选工艺流程,得到了钴品位为0.84%,钻回收率为87.64%钴分选指标；浮选尾矿采用一次粗选一次精选的强磁选工艺流程得到了锰品位为30.12%,锰回收率为72.37%的锰分选指标。结合浮选钴精矿的XRD衍射分析、硫物相分析、砷物相分析及化学成分分析结果得出,浮选钴精矿要通过物理的分选方法进一步提高钴品位及回收率是很困难的。为进一步提高钴的分选指标,对浮选钴精矿采用硫酸化焙烧—浸出进行了分离钴试验研究。试验结果表明,由于浮选钴精矿中CaO、MgO、SiO2、Al2O3等杂质含量较高及钴矿物的嵌布特征,呈现钴的浸出率低、耗酸量大、固液分离困难等问题。导致在焙烧温度为600℃、焙烧时间为3h、浸出液固比L/S=3、浸出时间为3h、浸出pH=1的综合工艺条件下,钻的浸出率仅为71.05%,脱硫率为82.86%。因此,硫酸焙烧—浸出工艺分离钴不可行。由于硫酸化焙烧—浸出分离钴指标较差,因此,采用氯化离析—弱磁选矿相重构法进行了深入的分离钻试验研究,在氯化离析过程中添加赤铁矿作为钴离析的活化剂,热力学分析结果也验证了赤铁矿的活化作用；添加石灰调整离析物料硅酸度,促进反应进行的同时使硫砷得到了固定,硫主要形成硫酸盐,砷主要形成砷酸盐；添加氯化亚铜作为催化剂,使离析时间从75min缩短至45min。在离析温度为1100℃、离析时间为45min、焦炭用量为7%、焦炭粒度为-0.5+Omm、氯化钙用量为11%、硅酸度R4=0.70、赤铁矿(含铁66.78%)用量为5%、氯化亚铜用量为1%、磨矿细度-0.045mm占90%、弱磁选磁场强度H=0.15T的氯化离析—弱磁选分离钻工艺条件下,得到了钴品位为4.18%,钴作业回收率为96.14%的离析钴精矿分选指标。对氯化离析过程产生以氯化氢气体为主的尾气进行了初步再生利用试验,试验结果得出采用石灰水吸收尾气可使Cl-的吸收效率达到75.27%,再生氯化钙可作为氯化剂返回使用,且钴的离析指标也比较理想。为考查钴锰选冶联合全工艺流程选别指标,进行了浮选—强磁选—氯化离析—弱磁选全工艺流程试验。在前面所取得的综合工艺参数条件下,得到了钴品位为4.18%,含镍1.92%,钴回收率为82.64%的钴精矿；锰品位为30.12%,含镍0.18%,锰回收率为72.42%的锰精矿,实现了汉源沉积型钴锰矿钻锰的综合利用。为揭示浮选钴精矿在氯化离析焙烧矿相重构过程中的演变机理,为此分别对浮选钴精矿和离析产品进行SEM矿相与EMPA成分分析,分析结果显示钴矿相从硫钴矿(硫镍钻矿、辉砷钴矿)转变成为以铁钴镍为主的新矿相—钴铁矿。依据现有新相生成理论、氯化离析冶金动力学模型及分析研究结论,提出氯化离析矿相重构过程中的“气—固相颗粒结构变化模型”,并对动力学模型进行了数学分析,分析结果得出在氯化离析过程铁钴镍主要以金属粒子形式存在,正是由于固体粒子结构发生了变化,最终新成了新的“钴铁矿”矿相,同时也形成了部分“钴黄铁矿”矿相。本论文针对汉源沉积型钴锰矿,采用“浮选—强磁选—氯化离析—弱磁选的选冶联合新工艺”进行试验及机理研究,尤其是获得了钴品位为4.18%,钴综合回收率为86.24%的钴精矿,打破了目前仅仅对锰进行回收的局面,对汉源沉型钴锰矿石的综合利用奠定了重要的试验基础与理论依据。更多还原

【Abstract】 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.更多还原