Advanced Materials Research Vol. 868

Abstract: In this study, an iron ore was investigated with high content of phosphorus and sulphur about 1.09% and 1.4%, respectively. The grade of Fe is about 30%, which is mainly composed of siderite, about 23.40% of iron is existed in the form of silicate, such as chlorite, canbyite, and a small amount of pyrite, magnetite. The phosphorous mainly occurred as apatite, which is close united with the phase of iron, and the sulphur mainly comes from pyrite. According to the mineralogy analysis of run-of-mine, acid leaching and reduction roasting with sodium carbonate is used for the high efficiently dephosphorization and desulfurization. Magnetic tube experiment after reduction roasting with sodium carbonate, an iron concentrate with 84.5%, Fe was produced with 69.7% relative recovery as a result of magnetic tube experiment carried out with 3A electric current.

Abstract: Microwave drying characteristics of Xilingol lignite were investigated with microwave drying testing equipment at 2450 MHz. Effects of particle size has been carefully studied. Mass losses of the samples were measured during drying. Drying rates were then obtained through the trends of drying curves. Results show the 0.6-1mm sample has low drying rate. Changing the stacking superficial area and size composition has been tested and resulted that only mixed with fine coal can increase the drying rate of 0.6-1mm. But classification experiment shows sieving 0-6mm sample into fine sample and coarse sample cannot advance the drying rate obviously.

Abstract: Properties of the ore were studied by chemical analysis, X-ray diffraction analysis and optical microscopy analysis. Research results show that the ore contains 479.5 g/t of silver and 0.54% of copper. Silver minerals are mainly argentite, copper minerals are mainly chalcopyrite and digenite, and gangue minerals are mainly quartz and dolomite. Based on the properties of the ore, flotation feasibility study was conducted. Results show that concentrate with excellent test indexes that a Ag grade of 4787.31 g/t with a Ag recovery of 87.97% and a Cu grade of 6.01% with a Cu recovery of 87.92% were obtained under the used process and reagent system conditions.

Abstract: Single flotation collector can not effectively extract the various valuable minerals from the complex ores simultaneously. Combined use of many collectors is one of the best ways to solve the problem, because the synergistic effect induced by the multifunctional composite chemical reagents will exert positive effect to the flotation and increase the recovery. The synergy is related with the reagent types, characteristics, and component contents in the mixture, and it is critical to choose and design the combination of various reagents. The maximal effect from synergy can be obtained easily by confecting the blended reagents. So the use of mixed collectors on the flotation of minerals has both benefits of reducing the costs and increasing the flotation efficiency.

Abstract: The leaching kinetics of high-phosphorus iron ores in HCl solution was investigated. The effects of temperature ranging from 27°C to 50°C, particle size from 0.18-1.25 mm and HCl concentration from 0.5 to 3.5 mol·L^-1 on the leaching efficiency of phosphorus were determined. The dissolution rates are significantly influenced by the temperature and concentration of acid solutions. The experimental results have been analyzed using the shrinking core model for diffusion control. The calculated apparent activation energy of the process is about 43.48 kJ·mol^-1, and a reaction order with respect to HCl is 0.64.

Abstract: Adsorption of silver ions by Thiourea (T) and Formaldehyde (F) resins in aqueous solution was investigated, where the TF resins were prepared by a one-step reaction catalyzed with acid or by a two-step one with base and acid, respectively. Effects of the reaction factors, such as the synthesis method, the monomer molar ratio and the amount of acid, on the TF resin adsorption performance were examined. According to Langmuir monolayer adsorption theory, experiments and theoretical calculations were designed to acquire the maximum adsorption capacity of silver ions.

Abstract: In this paper, considering on the real threshold pressure gradient (TPG), the mathematical model for low velocity non-Darcy unstable gas flow was established for the tight gas reservoir. Based on the low velocity non-Darcy unstable gas flow model, the gas flow model in heterogeneity formation was developed, and the analytical solution was obtained on the condition of constant production for inner boundary. Then we calculated the model numerically by Matlab programming. Its analyzed that the pressure distribution and the influencing factors such as production rate, producing time, reservoir thickness and the threshold pressure gradient. We compared the heterogeneity formation with the homogeneous formation by the heterogeneity low velocity non-Darcy unstable gas flow model, which shows great difference and illustrate the significance of research on heterogeneity.

Abstract: Five kinds of new tracers of high temperature and high salinity resistant were screened in order to meet tracer monitoring requirements in Tarapoa block at Dorine oilfield, these tracers were evaluated according to the tracer selection criteria, the optimal detection method was also studied in this paper. It showed that new tracers can adapt to high temperature, high salinity of the formation conditions, so as to meet adjacent multi-well groups monitoring requirements. Tracer monitoring can provide basis for the next step implementation of the program and the adjustment of measures, of a bright application future.

Abstract: MG-solid gas source is mainly composed of PH (phenols) and NI (nitrate) two kinds of solid components, in the presence of catalyst, which will start to react and produce CO₂, N₂ and RNH₂(R: methyl or H) mixed gas at 50°C ~ 380°C (adjustable) called MG for short. Its profile control, heavy oil viscosity reduction and cleanup functions can be widely used in heavy oil thermal recovery, better than the N₂ gas.

Abstract: A numerical model is established to simulate gas injection with high pressure for CBM cave completion. The model is used with the discrete element simulation software UDEC and considers two kinds of fracture morphology exiting in coal bed face cleat and butt cleat. The effective stress of coal matrix, fluid pressure and vector distribution of calculation nodal displacement under the influence of crustal stress is studied as bottom-hole pressure increases. Results show that the model considering cleat system can simulate reservoir fluid migration and matrix deformation more accurately in the process of pressure buildup of cavity completion; the different fluid velocities caused by different directions of face cleat and butt cleat will induce shear fractures for coal bed; the development of coal reservoir extensional fractures can be known by calculating the vector distribution of nodal displacement; the anisotropic formation stresses will make the break and collapse of coal bed more easily.