The reuse of abandoned Acquaresi mine voids for storage of the Masua flotation tailings

Often in abandoned mine sites are present both underground voids produced by mining and the tailings of treatment plant.An interesting solution for the rehabilitation of the sites would be to place the tailings of the process in the underground mining voids,thus obtaining the reclamation of surface areas and the stabilization of abandoned voids to prevent the dangerous phenomena of subsidence.However,these operations require inert waste,which must not be source of pollution,and the choice of a water/solid optimum to ensure good conditions of pumpability.

Preparation and properties of porous ceramics from spodumene flotation tailings by low-temperature sintering

Porous ceramics were prepared with spodumene flotation talings(SFT),kaolin and low-melting point glass(LPG)powder,whose pores were formed by the chemical reaction of hydrogen peroxide(H_(2)O_(2)).LPG was used to reduce the sintering temperature of porous ceramics and kaolin was used to realize the adsorption to methylene blue(MB)of porous ceramics.The average flexural strength,compressive strength,apparent porosity,water absorption and maximum MB adsorption capacity were 5.60 MPa,4.66 MPa,52.27%,44.32%and 0.7 mg/g,respectively.Moreover,the results of orthogonal experiments present that the sintering temperature and the dosage of H_(2)O_(2)had great influence on the mechanical properties and apparent porosity of porous ceramics,respectively.The main reason for the improvement of mechanical properties of porous ceramics was that LPG gradually became soft with increasing the sintering temperature,which made the mineral particles adhere to each other closely.Kaolinite was not completely converted into metakaolin at 550℃,which might be the main reason why porous ceramics had adsorption properties.

Adsorption behavior of Pb^(2+) and Cd^(2+) ions on bauxite flotation tailings

The adsorption behavior of Pb2+ and Cd2+ ions on bauxite flotation tailings was investigated to demonstrate the adsorptivity of the bauxite flotation tailings.The adsorption percentage of Pb2+ and Cd2+ ions as a function of adsorbent dosage,solution pH value and shaking time were determined by batch experiments.The maximum adsorption percentage of 99.93% for Pb2+ ions and 99.75% for Cd2+ ions were obtained by using bauxite flotation tailings as adsorbent.The methods,such as zeta potentials,specific surface area measurements and the analysis of adsorption kinetics,were introduced to analyze the adsorption mechanisms of the Pb2+ ions on bauxite flotation tailings.The isoelectric point of bauxite flotation tailings shifts from 3.6 to 5.6 in the presence of Pb2+ ions.The specific surface area of bauxite flotation tailings changes from 12.57 to 20.63 m2/g after the adsorption of Pb2+ ions.These results indicate that a specific adsorption of the cation species happens on the surface of bauxite flotation tailings.Adsorption data of Pb2+ ions on the surface of bauxite flotation tailings can be well described by Langmuir model,and the pseudo-second-order kinetic model provides the best correlation for the adsorption data of Pb2+ and Cd2+ ions on bauxite flotation tailings.

Recovery of zinc and lead from Yahyali non-sulphide flotation tailing by sequential acidic and sodium hydroxide leaching in the presence of potassium sodium tartrate

The recovery of zinc and lead from Yahyali non-sulphide flotation tailing using sulfuric acid followed by sodium hydroxide leaching in the presence of potassium sodium tartrate was experimentally investigated.In the acidic leaching stage,the effects of pH,solid-to-liquid ratio and temperature on the dissolution of zinc from the tailing were explored.82.3%Zn dissolution was achieved at a pH of 2,a temperature of 40°C,a solid-to-liquid ratio of 20%and a leaching time of 2 h,whereas the iron and lead dissolutions were determined to be less than 0.5%.The sulfuric acid consumption was found to be 110.6 kg/t(dry tailing).The leaching temperature had no beneficial effect on the dissolution of zinc from the tailing.The acidic leach solution was subjected to an electrowinning test.The cathode product consisted of 99.8%Zn and 0.15%Fe.In the alkaline leaching stage,the Pb dissolution increased slightly in the presence of potassium sodium tartrate.More than 60%of Pb was taken into the leach solution when the leaching temperature increased from 40 to 80°C.The final leach residue was analyzed by XRD and XRF.The XRD results indicated that the major peaks originated from the goethite and quartz while minor peaks stem from smithsonite and cerussite.The XRF analysis demonstrated that the residue contained 70.3%iron oxide.Based on the sequential leaching experiments,the zinc and lead were excellently depleted from the flotation tailing,leaving a considerable amount of iron in the final residue.