查看更多>>摘要：In this study,the role of(NH4)2SO4 during the sulfurization of azurite and its response to flotation were investigated.The flotation results showed that adding(NH4)2SO4 prior to sulfurization decreased the for-mation of colloid in flotation pulp,and the floatability of the suppressed azurite caused by excess sodium sulfide was restored.After adding(NH4)2SO4 prior to sulfurization,the formation of Cu(NH3)2n+interme-diate products changed the path of the sulfurization reaction,which slowed the direct impact of HS-on the azurite surface.The nucleation rate was reduced,and the growth of copper sulfide crystal was improved.Covellite(syn,CuS)with larger crystal grains was formed on the azurite surface,thereby enhancing the mechanical stability of copper sulfide products onto the mineral surface.Therefore,the generated copper sulfide colloid significantly reduced,ultimately promoting the effective adsorption of xanthate on the azurite surface.
查看更多>>摘要：In order to make the slag from desulphurization and slag skimming(SDSS)to be comprehensively recy-cled and utilized,a combined process of beneficiation and building materials preparation was proposed to recover iron from SDSS,meanwhile to apply the remaining slag tailings as cement admixture.From this process,three iron-rich products were recovered in stages by clean gravity-magnetic separation,slag tailings were left.Slag powder was prepared by ultrafine grinding of slag tailings.The stability,set-ting time and cement mortar strength of the slag tailings cements(STC)which were mixed with Portland cement and slag powder were studied respectively.The results showed that a proper overall performance still could be obtained at the slag powder content of 30％.Chemical composition analysis,X-ray diffrac-tion(XRD)analysis,metallographic microscope and scanning electron microscope(SEM)analysis were employed to assess the characteristics of the SDSS and the products obtained from the whole process.The results indicated that the three iron-rich products could be used as a raw material for steelmaking and ironmaking and the relatively large amount of calcium silicate(C2S)and tricalcium silicate(C3S)in the slag tailings make the addition of slag powder into the Portland cement feasible.
查看更多>>摘要：In this work,the stable layer structure of serpentine,which seriously restricts the extraction of magne-sium,was broken down,and a nearly 94％leaching efficiency of Mg was obtained by adding 5％fluorite powder.Compared with the system without fluorite,the Mg leaching efficiency increased by 36.42％.This result was achieved because the complexation of fluorinion(F-)with Si in serpentine promoted a dis-torted tetrahedral orientation,which led to a loose crystal structure of serpentine and contributed to exposing more Mg for a remarkable increase in Mg recovery.It is suggested that fluorite powder could replace expensive assisted reagents in the leaching process,which would markedly decreased the cost.Moreover,an energy-efficient"solvent displacement crystallization"(SDC)method was employed to effi-ciently recover magnesium(99.04％)from pregnant solutions.At the same time,the reuse of fluorine-containing solutions was explored.
查看更多>>摘要：Investigation on the mineral-water interactions is crucial for understanding the subsequent interfacial reactions.Currently,the hydration mechanisms of smithsonite are still obscure.In this paper,the adsorp-tion of H2O at different coverage rates on smithsonite(101)surface was innovatively investigated using density-functional theory(DFT)calculations and molecular dynamics(MD)simulations by analyzing adsorption model,interaction energy,atomic distance,density of state,electron density difference,con-centration profile,radial distribution function and self-diffusion coefficient.We found that single H2O preferred to be dissociated on smithsonite(101)surface via the interaction of surface Zn with the Ow of H2O and H-bond between Hw of H2O and surface Os.However,dissociation adsorption and molecular adsorption coexisted on the smithsonite surface at a high coverage rate of H2O,and dissociation adsorp-tion remained the main adsorption mechanism.Moreover,we found the interaction between smithsonite surface and H2O was weakened as a function of H2O coverage,which was because the presence of inter-layer H2O and different layers of H2O decreased the reactivity of the smithsonite surface.The H2O is mainly adsorbed on the smithsonite surface by forming three layers of H2O(about 10-15 Å),with the ordering degree gradually decreasing.
查看更多>>摘要：In this work,a novel process consisting of calcining-slaking followed by gravity separation for the enrich-ment of niobium(Nb)and titanium(Ti)from carbonatite pyrochlore ore was proposed,validated and compared with the current mainstream flotation method.During calcining of the pyrochlore ore,within which the carbonates were transformed into lime.Subsequently,when the calcined ore was slaked,lime was transformed into hydroxide with fine particles which were amenable to gravity separation.After cal-cining at 900℃for 60 min,slaking at 90℃for 10 min with a liquid-solid ratio of 3∶1(mL/g),approxi-mately 40％of tailings can be removed by gravity separation,the recoveries of Nb and Ti were 94.7％and 91.0％,and the enrichment ratios of Nb and Ti were 1.61 and 1.43,respectively.The new approach exhibits high separation efficiency of carbonate gangue minerals and valuable minerals,satisfactory recoveries of niobium as well as titanium can be achieved.
查看更多>>摘要：Large amounts of solid wastes and flue gases are generated in iron and steel production process,probably leading to serious environmental pollution without duly handle.An innovative and green process of simultaneous reduction of zinc-bearing dusts and activation of low-rank coal was developed and its mechanism was clarified in this paper.Under the optimal conditions,the reduced zinc-bearing dusts con-taining low harmful elements(0.02％Zn,0.015％K and 0.03％Na)could be made as high-quality burden for blast furnace while the low-rank coal was transferred into K,Na-embedded activated carbon,which can be used as effective adsorbent for purification of SO2 and NO-containing flue gases.The solid wastes were successfully utilized to treat the flue gases through the process.The synergetic activation and reduc-tion mechanism in the process was revealed.The coupling effect between reduction reactions of metal oxides in the dusts and activation reaction of carbon in the coal promoted the simultaneous reduction and activation process.In the meanwhile,part of the potassium and sodium from the zinc-bearing dusts could be adsorbed by the activated carbon and played a catalytic role in the activation process.
查看更多>>摘要：Chlorite,as the most representative gangue mineral associated with specularite,of which the separation of these two minerals is difficult.This paper investigated the depression effect of taurine on specularite/chlorite separation via flotation experiments,adsorption tests,contact angle measurements,Zeta poten-tial detection,FT-IR measurements,and XPS analyses.The results of single mineral flotation indicated that chlorite could be depressed selectively by taurine with the recovery of less than 30％,but the floata-bility of specularite remains high with recovery rate of 81.77％at pH 10.The artificial mixed mineral flota-tion results confirmed the effectiveness of taurine as a depressant.Surface adsorption,contact angle,and Zeta potential detection revealed taurine primarily adsorbs on the chlorite surface,which hampered the DDA's subsequent adsorption and results in the chlorite's poor floatability.The FT-IR spectra and XPS analyses provided further proof that taurine adsorbed on chlorite surface as an electron donor,and part of the electrons transferred from the sulfonic acid group of taurine to metal ions during the adsorption process.In addition,the hydrogen bond between amino-group of taurine and O ions in chlorite surface was also formed in the adsorption process.Finally,optimized adsorption configurations of taurine on chlorite surfaces were proposed.
Lucas PereiraMax FrenzelMarkus BuchmannMarius Kern...
645-655页
查看更多>>摘要：Physical separation processes are best understood in terms of the behaviour of individual ore particles.Yet,while different empirical particle-based separation modelling approaches have been developed,their predictive performance has never been tested under variable process conditions.Here,we investigated the predictive performance of a state-of-the-art particle-based separation model under variable feed composition for a laboratory-scale magnetic separation of a skarn ore.Two scenarios were investigated:one in which the mass flow of the different processing streams could be measured and one in which it had to be estimated from data.In both scenarios,the predictive models were sufficiently general to pre-dict the process outcomes of new samples of variable composition.Nevertheless,the scenario in which mass flow could be measured was～4％more precise in predicting mass balances.The process behaviour of minerals present at concentrations above 0.1％by weight could be accurately predicted.Our findings indicate the potential use of this method to minimize the costs of metallurgical testwork while providing in-depth understanding of the recovery behaviour of individual ore particles.Moreover,the method may be used to establish powerful tools to forecast mineral recoveries for partly new ore types at a running mining operation.
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