Dan Liu

Process Optimization and Reaction Mechanism of Removing Copper From an Fe-Rich Pyrite Cinder Using Chlorination Roasting

The aim is to remove copper from a pyrite cinder by optimzing the chlorination roasting process using response surface methodology (RSM) and the reaction mechanism of chlorination roasting based on thermodynamic calculation was discussed. A quadratic model was suggested by RSM to correlate the key parameters, namely, dosage of chlorinating agent, roasting temperature and roasting time to the copper volatilization ratio. The results indicate that the model is well consistent with the experimental data at a correlation coefficient (R2) of 0.95, and the dosage of chlorinating agent and roasting temperature both have significant effects on the copper volatilization ratio. However, a roasting temperature exceeding 1170 °C decreases the volatilization ratio. The optimum condtions for removing copper from the cinder were identified as chlorinating agent dosage at 5%, roasting temperature at 1155.10 °C and roasting time of 10 min; under such a condition, a copper volatilization ratio of 95.16% was achieved from the cinder. Thermodynamic calculation shows that SiO2 in the pellet plays a key role in the chlorine release from calcium chloride, and the chlorine release reactions cannot occur without it.

Investigation on Beneficiation Strategy for Collophane

Phosphate being one of the three major nutrients required for agricultural plant growth usually presents as collophane in China. Since fine phosphate and other gauge minerals associate with each other and form intergrowth, the beneficiation of collophane is extremely difficult. In this paper, the flotation strategy for a low grade collophane ore from Guizhou province in China was studied in detail. Direct, reverse and direct-reverse combined flotation sheets were employed to collophane flotation. The results reveal that direct-reverse flotation is a suitable flotation flow sheet for this collophane ore. With direct-reverse flotation sheet, the grade of P2O5 in concentrate is 33%, which is improved by 3% comparing direct flotation and P2O5 recovery could achieve 80%. In addition, content of MgO decreased to 0.9%, which satisfied the requirement of wet-process phosphoric acid.

Efficient Utilization of Copper Sulfide Ore in Chile by Flotation

The valuable minerals of a copper sulfide ore in Chile, mainly consist of chalcopyrite and chalcocite as well as contain small amounts of cuprite. Gangue minerals are mainly chlorite, quartz, calcite, arsenopyrite, etc. Most are coarse-grained disseminated minerals, while some are fine-grained disseminated minerals. Flotation has been used for processing these ores. The grinding fineness, lime dosage, collector type and dosage all have influences on flotation results. In the present work, the best condition of grinding fineness, lime, and collector dosage was used to separate the copper sulfide and other minerals in the ores. The results showed that, in the grinding fineness of −74 μm accounting for 80%, the vast majority of copper minerals were to monomer dissociation. The flowsheet of one stage roughing, two stage scavenging, and two stage cleaning was adopted. The ideal results of 27.58% and 96.89% for the copper concentrate grade and copper recovery, respectively, were obtained.

Leaching characteristics and mechanism of copper flotation tailings in sulfuric acid solution

The copper deposit in Yangla zone of China is large, and its recovery is low only using flotation process. Therefore, the copper in the flotation tailings is leached by sulfuric acid can improve copper recovery. The factors affecting leaching process and the leaching mechanism were investigated in this study. Copper is leached at a rate of 53.8% when initial H2SO4 concentration is 0.428 mol/L, leaching temperature is 348 K, liquid-to-solid ratio is 3: 1, stirring speed is 300 r/min and leaching time is 60 min. Through combine the acid leaching process of tailings with the flotation process of raw ore, copper comprehensive recovery has been improved. Kinetics results show that the leaching process is controlled by internal diffusion with an activation energy of 9.796 kJ/mol. To characterize the mechanism of acid leaching, chemical analysis, X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy were used. The results indicate that the fine size of copper minerals and CaSO4 precipitation which generated during acid leaching process affected the leaching of copper minerals.

Beneficiation Experiment Study on Iron Ore in Yunnan Province

In order to provide essential information for enterprises to exploit the iron ore of Yunnan province in China, properties of the ore were analyzed. Experiments of the best grinding fineness analysis and magnetic separation current were conducted. The result show that the ore is martite; when the grinding fineness content below 74um is 95%, and magnetic separation current is 10A (0.8T), iron concentrate with a grade of 65.40% and a recovery of 90.49% can be obtained. Sulfur and phosphorus content in the iron concentrate is 0.057% and 0.011%, respectively.

Recovery Copper from a Complex Copper Sulfide Ore of Yunnan by Using Flotation

Copper ore is the main mineral for the large deposits. Copper minerals are mostly consisting of chalcopyrite, secondly consisting of bornite, there are traces of processing copper blue and malachite, the mineral is disseminated by coarse granularity. This mineral is easy to processing. Production process was using by the process of grinding-flotation. After grinding fineness, lime dosage, sodium sulfide dosage, collector and frother dosage, were determined by the open test. Closed circuit experiment was conducted by those optimal conditions identified in the above test, the recovery of copper concentrate is 88.38% and the grade of copper concentrate is 14.37%.

Theoretical Calculation of Dissolution Equilibrium for Galena in Pulp Solution

The dissolution equilibrium of galena within the entire pH range was theoretically calculated, which was based on coordination chemistry, thermodynamics and the mass balance principle of Pb2+ and S2- in pulp solution. The calculation result showed that the total lead concentration (CPbT) of galena decreased significantly with increasing pH below 7 or so; however, at pH of about 10, a reverse trend of CPbT may be observed. Within the pH range from 7 to 10, the CPbT of galena remained close and presents a minimum value of around 10-10 mol/L. This paper may provide a theoretical basis for the dissolution process of galena and its conditioning stage before benefication by adopting flotation method.

Research on Reducing Direct Current Consumption of Copper Electrical Product

The main cost in the production of copper with leaching - extraction - electrical product method come from raw ore, electricity consumption and H2SO4 consumption. In this paper, methods of reducing direct current consumption of copper electrical product were determined. With high standard anode plate, Shorten appropriately hemimorphic spacing, controlling suitable current density and electric fluid temperature, fluid composition control reasonable electricity, short circuit and earth leakage was avoided and copper electrical product power consumption effect was highly reduced.

Internal Geometric and Electronic Structures of Natural Bornite Crystal

The geometric and electronic structures of bornite (Cu5FeS4) were studied using the first-principle calculation based on density function theory. By analyzing the results, a mixed bonding state is found in bornite, which is a strong covalent bond with much weaker ionic bonds. The interaction between S and Fe is stronger than that between S and Cu. The main bonding orbitals are as follows: Cu: 3d104s1, S: 3s23p4, and Fe: 3d64s2. Fe center is to be reduced receiving electrons in its 3d orbitals and the S center is mostly to be oxidized.

Recovery of Copper from Flotation Tailings by Leaching

A technology route of Reverse flotation of acid-consuming gangue mineralsAcid leaching for copperExtractingElectrodepositing is proposed for recovery copper from a tailings with high content of calcium oxide and magnesium oxide and high content of combined copper oxide. The effect of H2SO4 concentration, leaching time and stirring speed on copper leaching was investigated. The leaching solution obtained under the optimal copper leaching conditions, was used to be proceeded for extracting and electrodepositing test. The best leaching conditions are stirring speed of 30 m/min, H2SO4 concentration of 150 Kg/t ore, leaching time of 30 minutes. Under the best conditions, the acid leaching test presented that the production of per ton copper consumes sulfuric acid of 17.31 t, and Cu leaching rate is 84.70%.