Yue Xin Han

Fundamental Research in Utilization of an Oolitic Hematite by Deep Reduction

Oolitic hematite is an important iron ore resource. Because of its special feature，it can not be effectively separated by conventional beneficiation method. A new reduction and separation processe was used to treated an oolitic hematite in This study. The main factors influencing reduction was determined in the test. The main performance indexes of the product from this process were described as follows: iron grade>85%; metallization rate>97%; iron recovery>92%.

Toughening of Polypropylene with Calcium Sulfate Whiskers Treated by Coupling Agents

Calcium sulfate whiskers are modified by three kinds of coupling agents. The modified calcium sulfate whiskers are then introduced into polypropylene to prepare calcium sulfate whiskers/PP composites. Mechanical strength tests show that notched izod impact of polypropylene increases dramatically by adding calcium sulfate whiskers. When a silicane coupling agent KH-570 is adopted to modify calcium sulfate whiskers at 30 % (w/w) of whiskers, the notched izod impact of composites can increase by nearly 60 %. SEM is utilized to observe the impact fracture surface morphology of the composites and the distribution of calcium sulfate whiskers in the PP matrix. The results indicate that the surface treatment can promote uniform distribution of calcium sulfate whiskers in the PP matrix, and improve the notched izod impact and toughness of composites. Coupling agents play a role in toughening for the calcium sulfate whiskers/PP composites.

Cubic-Shaped Nano-MgO Powder and its Infrared Absorption Properties

A precipitation-pyrolysis process was used for the synthesis of cubic nano-MgO powder. The main effect factors on the size and shape of nano-MgO powder such as mechanical stirring rate, organic reagent, and calcinations of the process were investigated. XRD and TEM were used to study on composition, morphology and size of nano-MgO powder. The results indicate that at the condition of mechanical stirring rate 510 rmp, glycol as organic crystal controller, calcination time 3 h, cubic nano-MgO powder was prepared with average size of 35 nm. FTIR results show that cubic nano-MgO powder has abnormal infrared absorption behaviors compared with that of micron scale.

Preparation of Nano- MgO and Investigation of its Infrared Absorption Properties

A precipitation-pyrolysis process was developed for the synthesis of MgO nano-particles with diameter of 20~100 nm by using organic reagent, glycol, n-butanol and N,N-Dimethylacetamide, as shape and size controller. XRD and TEM were used to study on composition, morphology and size of the as prepared MgO nanoparticles. The results indicate that organic crystal controller is one of the key factors affecting the sizes and shapes of the nano MgO particles. When using glycol as a crystal controller, the dispersion of nano MgO particles is better and olive-shaped particles with sizes of 20~40 nm are prepared. When nano MgO particles are synthesized by MgCl2 and Mg(NO3)2, their particle sizes are smaller and their particles with olive shape. During chemical reaction process, Mg(OH)2 particles are already formed to be nano scale. Calcination process at the temperature of 650°C can change the crystal shape slightly. FTIR results show that nano MgO particles have abnormal infrared absorption behaviors compared with that of micron scale.

Pilot Beneficiation about Deoxidized Samples of Bayan Obo Oxidized Iron Ore

The composition of Deoxidized Samples of Bayan Obo Oxidized Iron Ore is complex with high content of residual reducing C, Fe phase in the RDP is ferrous metal what is hard and malleable resulting in pessimistic grindability. Gravity-magnetic separation process flow is adopted with C pre-rejecting, stage grinding (-0.074mm -57.18%, -0.074mm -85.66%) and coarse-fine fraction separate treatment base on RDP process characteristic. The final concentrate has 92.02% Fe with 93.27% Fe recovery, 94.18% Fe metallization which may utilize as rough materials for steelmaking and the final tailings has 15.10% REO with 97.15% REO recovery which may utilize as rough materials for REO concentration.

Research on the Reaction Behavior of Rare Earth Elements in Reduction

Occurrence state of rare earth elements in the different deoxidization stages and the behavior of rare earth elements in the process of depth reduction were studied by analyzing XRD and SEM images of Bayan Obo oxide ore in different deoxidization time. The results showed that deoxidization time had a great effect on the occurrence state of rare earth elements. With the increase of deoxidization time, rare earth minerals gradually translated from bastnaesite and urdite into (CaO•2Ce2O3•3SiO2).This phase was white with a small size. It was columnar or massive in most cases and could be easily separated from the iron phase. 97.18% of the rare earth elements, which could be recovered by flotation, gravity separation and magnetic separation, entered the iron tailings.

Research on Performance of the Modified Asphalt by Diatomite-Cellulose Composite

The diatomite-cellulose composite (DCC) was used to modified asphalt for pavement in the study, and then the high temperature performance, low temperature performance and temperature susceptibility of asphalt were studied. The results showed that these performances of asphalt were all improved after modified by DCC, and the performance of modified asphalt significantly associated with the ash content of DCC, and H-3 DCC was the best. The performance of modified asphalt by DCC was obviously better than using diatomite and cellulose directly. The improving properties of modified asphalt by DCC were caused by synergistic effect of diatomite and cellulose.

Experimental Study on Extracting Humic Acid from Lignite

Humic acid has been extensively used in the fields like industry, agriculture, medicine, environment protection, etc. As a kind of potential organic resources that being developed and utilized, humic acid is drawing more and more attention from the world. China is abundant in coal resource; the lignite of China contains a lot of humic acid. Extraction humic acid from lignite creates favorable conditions for the development of coal industry and agriculture industry, has broad utilization prospect. By combining the method of nitric acid preoxidation and the method of alkali solution and acid eduction, the humic acid was extracted from the lignite. The orthogonal experimental method and FTIR were integrated in this study. The influences of nitrate concentrations, acid-coal proportion, oxidized temperature, oxidation time, extraction liquid concentration, liquid-solid ratio, extraction temperature and extraction time etc. on the process of extracting humic acid were examined. The results indicate the optimal processing condition can achieved when using sodium pyrophosphate and sodium hydroxide solution as the extraction agents, the rate of humic acid production can reach to 39.25%. And the total content of humic acid production can reach to 46.14%.

The Research on the Performance of Asphalt Mastics Modified by Mineral Fillers

For a long time, the mineral additive was regarded as inert filler which had no reaction with the asphalt, so does the concrete mix. But some research conducted in the recent year proved that was not the case. In this study, four types of mineral materials (diatomite, kaolin (China Clay), Na-bentonite and Ca-bentonite) were selected out to investigate their effect on the asphalt mastics. The high temperature performance, low temperature performance and the temperature susceptibility of the asphalt mastics were evaluated. The result showed the diatomite rank first of the four minerals. The porous structure, huge specific area, mineralogical surface characteristic and the irregularity might be the reason for its positive effect. The bentonite, especially Na-bentonite is unfavorable to the asphalt modification.

Study on Flotation Mechanism of Separation of Potassium Feldspar from Quartz with Anion and Cation Mixed Collector

Potassium feldspar and quartz are all silicate minerals with frame structure,and have the similar crystal structure and physicochemical properties. Therefore, flotation has become the main method to separate potassium feldspar from quartz. The separation of potassium feldspar from quartz with anion and cation mixed collector was studied in the paper. The sodium oleate and sodium dodecyl benzene sulfonate were respectively used as collector agents in potassium feldspar and quartz single mineral flotation tests. The analysis of the variation of the surface properties of potash feldspar and quartz after using the collectors was conducted with infrared spectra and electrokinetic potential, followed by the mechanism of separation of potassium feldspar from quartz with anion and cation mixed collector.