Papers by Author: Xian Jun Lu

Abstract: According to XRD, DTA and SEM detections, the hydration products of blast furnace slag based cementing material SL, SLG. were studied in different age periods. The XRD analysis of cementing material SL hydration products showed the composition of hydration products were mainly amorphous substances, few crystalline substances. Characteristic peak of ettringite, such as AFt, hadn’t been found in the spectral line of DTA, and it hadn’t been found in the figures of SEM, either, which was accordant with the conclusion that the cementing performance of SL mainly coming from gel of hydrated calcium silicate (CSH) and hydrated calcium aluminate. But the cementing performance of SLG mainly coming from Aft, CSH and AFm from hydration products analysis of different age periods.

Abstract: Adsorption Characteristics and controlling methods of long-chain alkyl ammonium cations in montmorillonite interlayer space are theoretic evidence of the montmorillonite/alkylammonium complexes in the process of preparation. This paper summarizes the advances in research on adsorption characteristics of alkyl ammonium in montmorillonite inter-layer space.

Abstract: The blast-furnace slag （BFS）has been characterized by chemical and phase composition to evaluate its hydration reactivity. It has high potential activity for its glassy structure, so its use to prepare new filling cementation material is possible. New backfilling cementation material composition has been formulated and optimized by activation of BFS. The optimal formula of new backfilling cementation material SL(Slag activated by lime) and SLC(Slag activated by lime and calcium chloride) was 87% BFS ,13% lime and 86.84% BFS, 13.02% lime, 0.14% calcium chloride respectively. Finally, the feature of cementing properties was analyzed through comparison between new cementation material and ordinary Portland cement with compressive strength, water requirement of normal consistence, setting time, bleeding water and slump. The result showed that material SL and SLC have superior performance to ordinary Portland cement used to mining cemented filling.

Abstract: In this article we collected bentonite samples from cities including Weifang, Laiyang and Laixi in Shandong province of China and tested their cation exchange capacity (CEC) . Orthogonal tests were designed to optimize the process parameters on acid activation. There are three quality indexes including activation degree(AD), bleaching capacity(BC) and decolorization ratio(DR) in the tests. Correlation between CEC and three quality indexes, CEC and activation strength were studied, as well as the correlation among the three quality indexes. The results show that AD and DR decrease with CEC’s diminution, while BC has no regular change with CEC’s decrease. In order to get large value of the three quality indexes, the activation strength needs increase along with the CEC’s diminution.We also find that the correlation among the three quality indexes vary with CEC. Judging by CEC, their correlation and the least energy consuming, activated clay of the best property and the various application can be prepared.

Abstract: The research has conducted a experimental research on the issues in modifier of flotation process in a molybdenum ore concentrating mill in Inner Mongolia. The results show that: when the raw ore is grinded into 61% -200 meshes, which is the same to the site production ore, the sorting index is optimum in neutral magma condition; and for dispersing agent, the sorting effect of sodium silicate is better than sodium hexametaphosphate, and the confirmed sufficient quality of sodium silicate is 300g/t.

Abstract: In order to research the colloidal and thixotropic performance of the inorganic gel prepared by high purity montmorillonite, this study uses the moderate grade bentonite ores from Weifang (China) as raw material. Two-stage hydrocyclone classification was applied to obtain the high purity montmorillonite with its content of 94.8 per cent. In contrast to other methods of montmorillonite purification, two-stage purification by hydroclone has the advantages of larger throughput and easily achieving auto-control in industry, and products with different montmorillonite content can be obtained by this method. And then the inorganic gel was prepared by the prepared high purity montmorillonite , its colloidal and thixotropic performances were further studies. Research results show that the inorganic gel belongs to plastic body liquidity, the viscosity decreases with the increase of the shear rate, the static and dynamic shearing stress values are 33.98 Pa and 91.89 Pa respectively, and the thixotropic value is 95.2 dyne·s/cm², which indicates that it has preferable colloidal and thixotropic performance. Montmorillonite inorganic gel prepared by bentonite with high montmorillonite content and low- layer charge has better gel performance. The application result of inorganic gel in dentifrice and medicine shows that it has excellent effect.

Abstract: Al-pillared montmorillonite (Al-PILM) prepared with Keggin ions was studied by means of XRD, SEM-EDS and N₂ adsorption-desorption isotherms.The rusults show that, compared to unpillared Na-montmorillonite (Na-M), the interlayer spacing d₍₀₀₁₎ value, BET specific surface area, surface fractal dimension and the proportion of microporous specific surface area of Al-PILM are larger and the surface is relatively rough. The BJH porous volume distribution of Al-PILM is the most probable distribution, and the most probable pore size is about 2 nm, belonging to mesopore. The porous structure of Al-PILM is characterized as parallel plate slit or “house-of-cards” wedge-shaped pore which is formed by novel meso-microporous delaminated structure and fragments. Besides, the results of elemental distribution show that the ions exchange action between Na⁺ and hydroxy-Al cations in pillaring solution occurs in the formation of Al-PILM.

Abstract: In order to study the stability of Montmorillonite / Octadecyl trimethyl ammonium complexes in engineering application, the influences of the organic modifier dosage, oscillation intensity, oscillation time, temperature, pH, sodium salt concentration, calcium salt concentration on the stability of Montmorillonite / Octadecyl trimethyl ammonium complexes were systematically investigated. Research results show that the stability of Montmorillonite / Octadecyl trimethyl ammonium complexes slightly reduces with the increases of oscillation intensity, oscillation time and temperature, but the impact isn’t obvious. The more the organic modifier dosage is, the more unstable the Montmorillonite / Octadecyl trimethyl ammonium complexes are. The stability of the Montmorillonite / Octadecyl trimethyl ammonium complexes decreases significantly under the medium conditions of lower or higher pH. The higher the concentration of sodium salts is, the more stable the Montmorillonite / Octadecyl trimethyl ammonium complexes are, but calcium salts are on the contrary.

Abstract: In order to study the phase of Fe and Ti in a beach placer , different methods such as the X-ray diffraction analysis, chemical analysis, scanning electron microscopic , electron probe microanalysis are used to study the characteristics of the beach placer . The research results show the major metallic mineral in the beach placer is titanic magnetite, EDS and energy spectrum map features of which indicate that the vast majority of titanic magnetite contain a certain amount of Ti , the two elements of Fe and Ti take on closely symbiosis and distribute more evenly in titanic magnetite. The Ti exists in the Magnetite lattice in form of isomorphism. The theoretical highest grade of Fe and Ti in the separated Magnetic concentrate are 66.02per cent and 4.86 per cent respectively. In addition, the beach placer contains a small quantity of Ilmenite which is hysterogenic and exists in the form of fine solid solution separation structure in the titanic magnetite

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.