STUDY ON MECHANISM OF MIXED COLLECTORS IN SEPARATION OF FELDSPAR AND QUARTZ

Acidless and fluoless flotation is a new method for sepa-rating feldspar from quartz at the natural pH value of tap water in the ab-sence of any acid and fluoride and other inorganic reagents.The paperdiscusses the mechanism of mixed collectors in separation of feldspar andquartz by means of mono-mineral flotation experiment,determination ofsurface-tension,analisis of fluorescence,infrared spectrum,Auger electron sepectrum,and quantum chemistry calculation.     

STUDY ON STRUCTURE AND PROPERTY OF Nb-DOPED TiC CERAMIC WITH QUANTUM CHEMISTRY CALCULATIONS

Nb-doped TiC ceramic,or (Nb_yTi_(1-y)) C_x, inwhich amount of Nb element added is increased from zero to40Wt.%, synthisized with self propagating high temperaturesynthesis, is studicd with SCF-Xa-DV,a quantum chemistry cal-culating method. The chemical bonding is studied to discuss therelation between structrues and properties. Several classes ofmodels in which there is no vacancy,one vacancy or two vacan-cies have been calculated. From the calculated results of bond or-der, a measure of covalent bond strength, and molecule orbitalcontotr map, it is concluded that when Nb element added in-creases, the vacancies increase correspondinigly, the covalent com-ponent of chemical bonds of the samples decreases while the met-al-bonding component increases, so the hardness and resistanceof the samples decrease.     

STUDY ON SOLUTION CHEMISTRY BETWEEN TANNIC ACID AND THE FLOTATION PULP OF WOLLASTONITE AND DIOPSIDE

The mechanisms of interaction betweentannic acid and calcium ions either addedexternally to or inherently present in the volution(dissociated from mineral surface),arestudied by the use of Inductively Coupled PlasmaAtomic Emission Spectroscopy(ICP-AES),Ultraviolet Spectroscopy(UV).It is found thatwollastonite has a high solubility in theconcentration of calcium ions,calcium ions areable to interact with tannic acid.     

STUDY ON CORROSION BETWEEN FLEXIBLE GRAPHITE AND METAL AND ITS PROCTECTION

In this paper,the mechanism of corrosion betweenflexible graphite which is used as a sealing material and metal is in-vestigated,the anticorrosive measures are introduced,and somemordern measures which should be paid attention are provided.     

GRADIENT VARIATION OF COMPOSITION AND QUANTUM CHEMISTRY CALCULATION OF(Ti-Nb)C-Ni COMPOSITE

(Ti,Nb)C Ni composite is prepared.Theanalyses of SEM,EPMA and TEM/EDAX show that (Ti,Nb)C-Ni consists of three phases,which are called interior,transitional and Ni phases respectively.Several models arecalculated by self-consistent-field variational Xa(SCF-DV-Xa)me thod,one of the quantum chemistry calculatingmethods.The calculated results show that when Ni elementincreases,the bond orders(measures of strength of covalentbonding)of Ti-C and Ni-C in the models decrease corre-spondingly,which is to say that there is a gradient variation of the covalent bond in the transitional phase which is compat-ible with both the interior and Ni phases.It is beneficial for improving the mechanical properties of the materials.     

STUDY AND APPLICATION OF SILLIMANITE FLOTATION AGENTS

Abstract:This paper,starting from the study on the surface elec-the-property differences between sillimanite in some chinese mine and itsmain intergrown silicates,detailedly inquires into the mixing function offatty acids and hydrocarbon sulfonic acids collecting agents on sillimaniteand based on this finds the optimum agent-blending system,so that it ispossible to realize the efficient effparation of sillmanite,mica and quartz.Through the single flotation closed-circuit experiment of hard-to-be-sepa-rated ores with hair-like corpuscles embedded,the authors have successivelyseparated out the sillimanite concentration (Al_2O_3 56. 31%;Fe_2O_3 1.07%;TiO_2 1.0%;alkalis 0.2% )from the raw ores (sillimanite 15%;Al_2O_319.92%;Fe_2O_3 1.90%;TiO_2 3%;alkalis 0.2%) and obtained the silli-manite flotation recovery as high as 70%.     

STUDY ON RELATIONSHIP BETWEEN MICROSTRU-CTURE AND PROPERTY OF MODIFIED BITUMEN

In this paper morphology of APP modified bitu-men(APP MB)and SBS modified bitumen(SBS MB)wasstudied by scanning elecron microscopy(SEM) and the mor-phology property relationship of these two modified bitumen(MB)was discussed.The results indicate that the APP MBsystem is in a homogeneous phase structure and the SBS MBsystem is in a heterogeneous phase structure.Improvement ofbituminous physical properties by APP and SBS is closely re-lated with the microstructure of APP and SBS MB.     

QUANTUM CHEMISTRY STUDIES ON THE STRENGTH PERFORMANCE OF ETTRINGITE

Ettringite is a main hydrate of cement,and theSr-bearing ettringite is a main hydrate of Sr-bearing calciumsuplhoaluminate.In this paper the two hydrates are studiedby a quantum chemistry method,the self-consistent-field dis-crete variation X_α.method (SCC-DV-X_α).The results show:their bond order of Al and covalent bond order of Al-O bondare alike;that the bond order of Sr and the covalent bond or-der of Sr-O in Sr-bearing ettringite are higher than these ofettringite is the main reason,that the strength of Sr-bearingettringite is higher than that of ettringite.     

STUDY ON STRENGTH AND PETROGRAPHIC STRUCTURE OF CLINKER BY LOW-TEMPERATURE BURNING

In this paper,the strength and petrographicstructure of clinker by low-temperature burning are studied.The results show that both the calcining temperature of Ca-CO_3,and sintering temperature clinker decreases by 150℃com-pared with those in traditional rotary kiln,the rate of f-CaOin the clinker sintered at 1300℃ is 0.29%～2.81%,thestrength of the clinker is 62.5MPa with maxium 69.4MPa ata specific area of 2900～3400cm~2/g.The results also showthat the types of petrographic structure of the clinker can beclassified as:homogeneous structure,inlaid or edged struc-ture,stain-melting structure and porous strncture.The clinkersintered at 1300±15℃ temperature and with enough reten-tion period is mainly in homogeneous structure.     

THE STUDY ON COLOURING MECHANISM OF THE COLOUR-TRANSITION GLAZE

The colour-transition glazed brick has beenmade under suitable conditions and the expectedresult has been-obtained.The chemical compositionsof the glaze have been given.The structures of Na_2O(K_2O)-CaO(MgO)-Al_2O_3-SiO_2 system,parent glaze and colour-transitionglaze have been invesitigated by SME,Visible spec-trum,IR spectrum and Raman spectrum.A brief exp-lanation to colouring mechanism of colour-transi-tion glaze was given in accordance with theory ofoptical absorption and scattering.For all specimens,liquid phase separationstructures were observed generally be SEM andacomparison between parent glaze and colour-transi-tion glaze was made by Visible specta.Hence aninference can be drawn from these results that theliquid phase droplets contain Nd~(3 ),Pr~(3 ) ions,which cause coloration selective absorbing andscattering of incident light waves.     

几种常用捕收剂与红柱石作用机理的量子化学研究

运用量子化学中RHF（Hartree-Fock-Roothaan）方法,利用STO-3G基组,研究红柱石晶体中各离子电荷分布及4种捕收剂与红柱石作用的键级与能量变化。经对红柱石与捕收剂成键机理分析表明,十二烷基磺酸钠为化学吸附,十二胺为物理吸附,油酸钠和羟肟酸为物理吸附与化学吸附共存。4种捕收剂按捕收能力从强到弱的排序为：十二烷基磺酸钠〉十二胺〉羟肟酸〉油酸钠。该排序结果与浮选试验结果一致。