Papers by Author: Jin Lin Yang

Abstract: In this paper, sulfuric acid leaching was carried out to assess the effect of several parameters on metal extraction in a low grade complex gossan ore in which the grade of zinc and iron is 13% and 40.2%, respectively. Parameters, such as sulfuric acid concentration, liquid to solid ratio and leaching temperature, were studied. The results show that the zinc leaching rate is almost 80%, while the iron leaching rate is about 45% used strong acid with 200g/L. It can be seen from the results that sulfuric acid leaching could not effectively recover zinc from gossan ores studied in this paper because of iron dissolving greatly.

Abstract: In recent years, recovering zinc from zinc calcine with high iron has been a matter of discussion. In this paper, sulfuric acid leaching was carried out to assess the effect of several parameters on zinc and iron extraction in zinc calcine with high iron in which the grade of zinc and iron is 53.90% and 19.38%, respectively. Parameters, such as stirring speed, sulfuric acid concentration, liquid to solid ratio and leaching time, were investigated. The results show that leaching time has done nothing to the leaching rate, but has great influence on leaching efficiency. Liquid to solid ratio and sulfuric acid concentration have significant influence on leaching results, and stirring rate has not obvious influence on leaching results. Under the condition of 120g/L sulfuric acid, 6:1 liquid to solid ratio, 55°C leaching temperature and 120min leaching time, the recovery of zinc and iron is 82.24% and 9.64%, respectively. It is obvious that ZnO in zinc calcine is easy to dissolve in acidity solution, which shown in two aspects: high leaching rate and high leaching speed. ZnO can be dissolved entirely in sufficient sulfuric acid in 10min.

Abstract: Flotation tests for recovering zinc and iron from gossan ores was carried out in this paper. Flotation is the most commonly used method for beneficiation and pretreatment of oxidized zinc minerals. The effects of grinding fineness, amount of Na₂CO₃, amount of Na₂SiO₃, amount of Na₂S and amount of octadecylamine were investigated, respectively. The results show that the grade of zinc and iron increase slightly, and the best result is that the grade of zinc and iron are 13.12% and 41.15%, the recovery of zinc and iron are 76.83% and 77.95%. The results simply indicated that flotation could not effectively recover zinc and iron from gossan ores studied in this paper.

Abstract: In recent years, recovering zinc from low grade oxidized zinc ore has been a matter of discussion. In this paper, the investigation for recovering zinc and iron from gossan ores was carried out. In generally, the conventional physical separation methods, such as flotation, gravity separation and magnetic separation, were used to treat the low grade ore, and flotation is the most commonly used method for beneficiation and pretreatment of oxidized zinc minerals. However, gravity separation and magnetic separation are used to deal with the gossan ores because of the special zinc oxide ore bearing iron 40.2% in this study. The effects of grinding fineness and magnetic intensity were investigated, respectively. The results show that the grade of zinc and iron increase slightly, and the best result is that the grade of zinc and iron are 13.35% and 40.25%, the recovery of zinc and iron are 53.45% and 52.19%.

Abstract: In this paper, the conventional physical separation method such as flotation, gravity separation, magnetic separation, alkaline leaching and sulfuric acid leaching were studied. The effects of grinding fineness, amount of agent, magnetic intensity, roasting temperature, roasting time, the leaching agent and leaching time on the leaching of zinc were investigated, respectively. The results show that the leaching rate of zinc is below 50% in the conventional alkaline leaching, and the leaching rate of zinc is below 85% and the leaching rate of iron is above 35% in sulfuric acid leaching. Compared with XRD pattern of the raw ore, the different diffraction peaks of smithsonite is off in alkaline leaching products. In sulfuric acid leaching, the different diffraction peaks of smithsonite are off in the leaching products when sulfuric acid concentration is less than 60 g/L. After 60 g/L, the different diffraction peaks of smithsonite and siderite are off in the leaching products.

Abstract: Zinc ferrite is usually formed during the roasting of zinc sulfide concentrate with high content of iron and reduces zinc recovery during the leaching of zinc calcine. Because it is difficult to find pure zinc ferrite in nature ore resources or in chemicals market, which impedes the investigation of the reaction characteristics of zinc ferrite and the seek of new technologies for zinc ferrite dissolution, so it is of significance to obtain relatively pure zinc ferrite for further research on zinc calcine leaching. This article investigated the preparation process of zinc ferrite based on the dissolution characteristics of a zinc calcine with 19.38% iron and put forward a method to judge the reaction end point during the leaching of zinc calcine to produce zinc ferrite. The results show that the product of zinc ferrite could be prepared through recovering the leaching residue during leaching the zinc calcine under the initial H₂SO₄ concentration equal to or larger than 160g/L, and that the leaching end point can be judged by comparing the experimental curve of Zn leaching with the zinc theoretical dissolvability curve.

Abstract: Flotation is a conventional way for treating low grade metal oxide ore which has some advantages such as high efficiency and low cost. In order to recover the zinc from a low grade complex zinc oxide ore in which the grade of Zn is 13 wt.%, this paper presents a preliminary investigation of this type of ore by flotation method. In the experiments, the effects of different parameters such as grinding fineness, amount of Na₂SiO₃, amount of Na₂S and amount of octadecylamine were investigated in relation to the metal contents of concentrates. The results show that about 35% of initial Zn content was obtained with 70% -200 mesh grinding fineness, 1000g/t Na₂SiO₃, 2000g/t Na₂S and 500g/t octadecylamine. It is clear that the preliminary flotation tests with the ore sample indicated that there was no selectivity in terms of zinc recovery. Almost 65% zinc remained in the tailings and could not be recovered by flotation due to its complicated mineralogical structure. Therefore, application of metallurgical processes is proposed for zinc recovery from the tailings in the following investigations.

Abstract: Al3+/clay ratio is one of the important factors influencing microstructure of Al-pillared montmorillonite. Microstructure variation laws of Al-pillared montmorillonite prepared under the condition of different Al3+/clay ratio are systematically studied by XRD, FTIR, specific surface area and pore size analysis. The results show that the interlayer spacing and BET specific surface area of Al-pillared montmorillonite are remarkably affected by the Al3+/clay ratio. The interlayer spacing d(001) value and BET specific surface area of Al-pillared montmorillonite increase firstly and then decrease with the increases of the Al3+/clay ratio, and they reach to maximum when the Al3+/clay ratio is 10mmol/g. Besides, the BJH porous volume distribution of Al-pillared montmorillonite is the most probable distribution, and the most probable pore size is about 2 nm, which is attributed to mesopore. The porous structure of hydroxy-Al pillared montmorillonite is characterized as parallel plate slit or “house-of-cards” wedge-shaped pore which is formed by novel meso-microporous delaminated structure and fragments. With the increase of the Al3+/clay ratio, BJH total porous volume and mesoporous volume of hydroxy-Al pillared montmorillonite decreases, while the proportion of microporous volume in the total porous volume increases. The proportion of microporous specific surface area of all the hydroxy-Al pillared montmorillonite samples is about 62% and is much larger than that of Na-M and those of mesopore and macropore, indicating the main action of intercalation of hydroxy-Al pillaring solution into montmorillonite interlayer is to increase the micropore amount.

Abstract: In this research, a leaching study was carried out to assess the effect of several parameters on zinc extraction in a low grade complex zinc oxide ore in which the grade of Zn is 13 wt.%, and 52.8% of Zn is contained in siderite, 34.63% in limonite and 11.55% in smithsonite. The influencing parameters investigated include sulfuric acid concentration, reaction temperature, reaction time and liquid to solid ratio (L/S). The results show that over 90% of Zn can be extracted from the low grade complex zinc oxide ore when the leaching process is operated in 2M sulfuric acid at 60°C for 2.5h with a liquid to solid ratio of 6:1.

Abstract: The microwave pretreatment of a typically refractory flotation gold concentrate was investigated. The results demonstrated that a maximum gold recovery of 97% was achieved, and that gold recoveries of the refractory gold concentrate quickly increased to the maximum with microwave heating time. Adding additives during microwave heating process was helpful to improve the leaching rate of gold, and the effect of microwave heating with single NaOH on the leaching rate of gold is not better than that of NaOH combined with other additives.