STUDY ON TREATMENT OF AMMONIA LEACHING SLAG IN THE METALLURGICAL PROCESS OF TUNGSTEN

ＳＴＵＤＹＯＮＴＲＥＡＴＭＥＮＴＯＦＡＭＭＯＮＩＡＬＥＡＣＨＩＮＧＳＬＡＧＩＮＴＨＥＭＥＴＡＬＬＵＲＧＩＣＡＬＰＲＯＣＥＳＳＯＦＴＵＮＧＳＴＥＮＳｕｎＰｅｉｍｅｎ；ＬｉＨｏｎｇｇｕｉ；ＬｉＹｕｎｊｉａｏ；ＬｉｕＭａｏｓｈｅｎｇ；ＳｕＰｅｎｇｔｕａｎ（...     

Decomposing scheelite and scheelite-wolframite mixed concentrate by caustic soda digestion

1　INTRODUCTIONWiththecontinualexploitationanddevelopmentoftungstenmaterials ,wolframitebecomeslessandless .Statisticaldatashowthattheproportionofwol framiteisonly32 .9%andthatofscheeliteis 4 5 .5 %intungstenresources ,therestisscheelite wolframitemixedconcentrateandmostofnewlyexploredtung stenisscheelite[1] .Therefore ,howtoeconomicallyexploitscheelitebecomessignificantlyimportantindevelopingtungstenindustriesinChina .Currently ,causticleachingisappliedtohandlewolframiteconcentrate ,andh…     

CAUSTIC DECOMPOSITION OF SCHEELITE AND SCHEELITE－WOLFRAMITE CONCENTRATES THROUGH MECHANICAL ACTIVATION

ＣＡＵＳＴＩＣＤＥＣＯＭＰＯＳＩＴＩＯＮＯＦＳＣＨＥＥＬＩＴＥＡＮＤＳＣＨＥＥＬＩＴＥ－ＷＯＬＦＲＡＭＩＴＥＣＯＮＣＥＮＴＲＡＴＥＳＴＨＲＯＵＧＨＭＥＣＨＡＮＩＣＡＬＡＣＴＩＶＡＴＩＯＮＬｉＨｏｎｇｇｕｉ；ＬｉｕＭａｏｓｈｅｎｇ；ＳｕｎＰｅｉｍｅｉ；...     

Free alkali recovery from NaOH leaching liquor of tungsten ore by electrolysis with ion-exchange membrane

Ｔｈｅｃａｕｓｔｉｃｓｏｄａｌｅａｃｈｉｎｇｌｉｑｕｏｒｏｆｔｕｎｇｓｔｅｎｏｒｅ（ｗｏｌｆｒａｍｉｔｅｏｒｓｃｈｅｅｌｉｔｅ）ａｌｗａｙｓｃｏｎｔａｉｎｓａｇｒｅａｔｄｅａｌｏｆｆｒｅｅａｌｋａｌｉｆｏｒｔｈｅｒｍｏｄｙｎａｍｉｃａｎｄｋｉ－ｎｅｔ...     

A new technology for production of high purity paratungstate ammonium from low grade tungsten concentrate

A new technological process for production of paratungstate ammonium from low grade tungsten concentrate with a high content of calcium and impurities has been studied. The experiments show that average tungsten leaching efficiency of more than 96.92% can be obtained with a low NaOH consumption by using the mechanical activating caustic decomposition, and the content of main impurities (P, As, Si) in Na₂WO₄ solution obtained is competitive with that from standard wolframite concentrate by traditional caustic decomposition. After recovering caustic soda by crystallization, impure Na₂WO₄ solution is changed to (NH₄)₂WO₄ solution by ion exchange method. Molybdenum may be removed from (NH₄)₂WO₄ solution by new ion exchange method. Finally, paratungstate ammonium of high purity is obtained. This technology has the advantages of short technological process, high recovery of tungsten, high economic and social benifits. Synopsis of the first author Sun Peimei, professor, born in 1945, specializing in rare metallurgy and hydrometallurgy.     

Isotope systematics and metallogenetic age of Zhuanghe gold deposit, Liaoning province, China

Based on the metallogenetic geology conditions, the H, O, C and S isotopic compositions were measured by MAT-251 mass spectrometer, and Pb isotope and Rb-Sr dating were carried with MAT-261 multi-acceptor mass spectrometer. The results show that the δ18O values of gold-bearing vein quartz from different levels are 1.19%-1.42%. The calculated δ18O values of ore fluids are 0.55%-0.78%, and δD values are from –8.64% to –6.66%. The calculated values of δ 34 SH2Sby the δ34Spy values in quartz veins display sulfur isotope compositions from -0.053% to 0.413%. Carbon isotope compositions of carbonates are from -0.612% to 0.140%. The mole ratios of 206Pb to 204Pb, 207Pb to 204Pb and 208Pb to 204Pb in auriferous quartz vein are 16.987-17.545, 15.342-15.623, and 38.254-38.744, respectively. The age of the Zhuanghe gold deposit determined by Rb-Sr isochron of the fluid inclusions in quartzes is (143.0±5.8) Ma. These isotopic data suggest that the metallogenetic fluids are generated from magmatic hydrotherm and the origin of ore-forming matters is related to the deep-derived magmatic activities. Meanwhile, the metallogenetic epoch of the Zhuanghe gold deposit is in Yanshanian period.     

Seismic ultimate bearing capacity of strip footings on slope

The influence of earthquake forces on ultimate bearing capacity of foundations on sloping ground was studied. A solution to seismic ultimate bearing capacity of strip footings on slope was obtained by utilizing pseudo-static analysis method and taking the effect of intermediate principal stress into consideration. Based on limit equilibrium theory, the formulae for computing static bearing capacity factors, Nq, Nc, Nγ, and dynamic bearing capacity factors, Nqd, Ncd, Nγd, which are associated with surcharge, cohesion and self-weight of soils respectively, were presented. A great number of analysis calculations were carried out to obtain the relationship curves of the static and dynamic bearing capacity factors versus various calculation parameters. The curves can serve as the practical engineering design. The calculation results also show that when the values of horizontal and vertical seismic coefficients are 0.2, the dynamic bearing capacity factors Nqd, Ncd and Nγd, in which the effects of intermediate principal stress are taken into consideration, increase by 4%?42%, 3%?27% and 34%?57%, respectively.     

Long-term Performance of Moderate Heat Portland Cement with Double-expansive Sources

The long-term performance of moderate heat Portland cement with double-expansive sources （DE cement） in the system of high MgO clinker and gypsum was studied by XRD, SEM/EDAX and test methods for strength and expansion of cement. Results indicate that the periclase particle, whose size was 5-7.5μm in DE cement clinker containing 4.8 % MgO, existed individually. The periclase hydration in hardened DE cement paste started at about 60 days and completed up to 2 000 days, and ettringite in the paste was stable from 3 days to 2 000 days. Under the conditions of 4.5%-5.0 % MgO in clinker and 2.8%-3.4 %SO3 in cement, ettringite expansion and brucite expansion in DE cement paste had a continuity, entirety and stability. At the ages of 90, 365,730 and 2 000 days the expansion of the paste reached 0.07%-0.11%, 0.16%-0.21%, 0.21%-0.27 %, and 0.29%-0.38%, respectively. The results suggest that by using this cement in mass concrete it may compensate its temperature shrinkage and autogenous shrinkage to some extent.     

Effects of water phase concentration on the emulsion polymerization of polyaniline

Ｄｕｒｉｎｇｒｅｃｅｎｔｙｅａｒｓｐｏｌｙａｎｉｌｉｎｅ(ＰＡＮ)ｈａｓｂｅｃｏｍｅｏｎｅｏｆｔｈｅｍｏｓｔｐｒｏｍｉｓｉｎｇｃｏｎｄｕｃｔｉｖｅｐｏｌｙ ｍｅｒｓｆｏｒｐｒａｃｔｉｃａｌａｐｐｌｉｃａｔｉｏｎｄｕｅｔｏｉｔｓｈｉｇｈｅｎｖｉ ｒｏｎｍｅｎｔａｌｓｔａｂｉｌｉｔｙａｎｄｈｉｇｈｃｏｎｄｕｃｔｉｖｉｔｙ[1 3] .ＰＡＮｃａｎｂｅｓｙｎｔｈｅｓｉｚｅｄｂｙｃｈｅｍｉｃａｌｏｘｉｄａｔｉｏｎａｎｄｅｌｅｃｔｒｏｃｈｅｍｉｃａｌｐｏｌｙｍｅｒｉｚａｔｉｏｎ[4 6 ] .Ｈｏｗｅｖｅｒ,ｔｈｅｃｏｎｊｕ…     

Flotation de-silicating from diasporic-bauxite with cetyl trimethylammonium bromide

1　INTRODUCTIONTheZetapotentialsofkaolinite ,illiteandchlo riteweremeasuredforthecoalflotation ,allthesethreeclaymineralswerenegativelychargedinthepHrangeof 2 .5 11.0 [1] .Theadsorptionofsodiumdode cylsulfateanddodecyltrimethylammoniumchlorideontokaolinitewasstudiedintheabsenceandpresenceofsodiumhexametaphosphate .Itwasfoundthatthepresenceofthelongchainphosphatedecreasedad sorptionoftheanionicsurfactantbutincreasedthead sorptionofthecationicsurfactant[2 ] .Acommercialmonoetheramineandac…     

Thermodynamic assessment of Au-Zr system

1　INTRODUCTIONChemicalvapordeposition (CVD)diamondholdsgreatpromiseinsolvingthermalmanagementprobleminhigh performancemulti chipmodules (MCMs) .However ,thismaterialdoespresentsometechnologi calchallenges ,onebeingthedevelopmentofreliablemetallizationsystems[1] .Thedesirablecharacteristicsofametallizationsystemare goodadhesiontothesubstrate ,lowstress ,goodelectricalconductivityandminimalreactionsatsubsequentprocessingtempera tures (upto 4 0 0℃ ) [2 ] .Goldisusuallychosenasthemetalfor…     

Fabrication and characterization of nano silver powder prepared by spray pyrolysis

Silver powder was fabricated by spray pyrolysis, using 2%–20% AgNO₃ solution, 336–500 mL/h flux of AgNO₃ solution, 0.28–0.32 MPa flux of carrier gas and in the 620–820 °C temperature range. The effects of furnace set temperature, concentration of AgNO₃ aqueous solution, flux of AgNO₃ aqueous solution as well as carrier gas on the morphology and particle size distribution of silver powder, were investigated. The experimental results showed that with the high concentration of AgNO₃ aqueous solution, the average grain size of silver decreased with the increasing of furnace set temperature. But the gain size distribution was not homogenous, the discontinuous grain growth occurred. With the low concentration of AgNO₃ aqueous solution, the higher furnace set temperature made the nano sliver grains sintered together to grow. Nano silver powder about 100 nm was fabricated by spray pyrolysis, using 2wt% AgNO₃ solutions, 336 mL/h flux of AgNO₃ aqueous solution, 0.32 MPa flux of carrier gas at 720 °C furnace set temperature.     

Forming regularity and relation between composition and property of B2O3-BaO-ZnO glass

B2O3-BaO-ZnO glass was prepared by using conventional melt quenching technology. The forming regularity and the relationship between the composition and the property of B2O3-BaO-ZnO glass were investigated. The results show that the composition range for forming B2O3-BaO-ZnO glass is very wide, but the content of B2O3 has a limit within mole fraction of 25%-75%. When the content of B2O3 is over the limit, the melt will be divided into two phases with different compositions and structures, whereas too low content of B2O3 will result in the crystallization of the melt during the cooling process. The thermal expansion coefficient, the transition temperature and the resistivity of the glass at room temperature are (5-10)×10-6 ℃-1, 480-620 ℃ and (1.5-3.0)×1010 Ω·m, respectively.     

SYNTHESIS，PROPERTY AND HEAT STABILITY FO RPOLYVINYLCHLORIDSOFANTIMONYTRIS（MERCAPTOACIDESTER）

ＳＹＮＴＨＥＳＩＳ，ＰＲＯＰＥＲＴＹＡＮＤＨＥＡＴＳＴＡＢＩＬＩＴＹＦＯＲＰＯＬＹＶＩＮＹＬＣＨＬＯＲＩＤＳＯＦＡＮＴＩＭＯＮＹＴＲＩＳ（ＭＥＲＣＡＰＴＯＡＣＩＤＥＳＴＥＲ）ＳＹＮＴＨＥＳＩＳ，ＰＲＯＰＥＲＴＹＡＮＤＨＥＡＴＳＴＡＢＩＬＩＴＹＦＯＲＰ...     

Antibiotic properties of Al2O3 doping silver

The preparation technique and properties of Ag-type inorganic antibiotic material carried by Al₂O₃ were studied. The results show that the material has good antibiotic and safety properties, the acute toxicity taken by stomata is LD ₅₀>8 000 mg/kg (little and big white rats), and the normal quantity in subacute toxicity test is 80 mg/(kg · d). The better mass fraction of doping Ag₂O in antibiotic material carried by Al₂O₃ is 4%–8%, and the optimal sintering temperature is from 1 000 °C to 1 100 °C. Foundation item: Project (2002AA327090) supported by National High Technology Research and Development Program of China     

Degradation of polyvinyl-alcohol wastewater by Fenton＇s reagent： Condition optimization and enhanced biodegradability

The pretreatment of refractory polyvinyl-alcohol (PVA) wastewater with low value of COD_Cr by Fenton’s reagent was investigated to enhance the biodegradability. The effects of operating conditions such as pH of the solution, Fe²⁺ dosage, H₂O₂ dosage, reaction time and initial PVA concentration on the removal efficiency of COD_Cr were discussed. It is demonstrated that the optimum value of pH for removal of COD_Cr is 5 and the most suitable dosages of H₂O₂ (2%) and FeSO₄ (10 mg/L) are 5% and 8.0%, respectively. When the initial COD_Cr value of the PVA water is 760 mg/L, the favorable reaction time is 110 min. Under these optimum conditions, the removal ratio of COD_Cr is 58.6%–61.4%, and the value of biodegradability (COD_B/COD_Cr) increases markedly from 8.9%–9.7% to 62.6%–68.3%.     

PROPERTY AND METALLOGENIC CHARACTERISTICS OF ALKALI-RICH PORPHYRY IN WESTERN MARGIN OF YANGTZE PLATFORM

Ａｌｋａｌｉ－ｒｉｃｈｐｏｒｐｈｙｒｉｅｓｏｆｔｈｅｗｅｓｔｅｒｎｍａｒｇｉｎｏｆＹａｎｇｔｚｅＰｌａｔｆｏｒｍｓｐｒｅａｄａｌｏｎｇＡｉｌａｏｓｈａｎ－Ｊｉｎ－ｓｈａｊｉａｎｇｆｒｏｍｗｅｓｔｔｏｎｏｒｔｈ；ｔｈｅｉｒａｇｅ，ｔｈｅｒｏｃｋｔｙｐｅ...     

Cemented backfill technology based on phosphorous gypsum

Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craftwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage (the mass ratio of cement to fly ash to gypsum) is 1:1:6–1:1:8 with mass fraction of solid materials 60%–63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7×10⁶ yuan (RMB), only 1/10 of that of traditional paste backfill system. Foundation item: Project (2006BAB02A03) supported by the National Key Technology Research and Development Program; Project (08MX16) supported by Mittal Scientific and Technological Innovation Projects of Central South University during 2008     

Pozzolanic Activity of Burned Coal Gangue and Its Effects on Structure of Cement Mortar

The pozzolanic activity of coal gangue burned at different burning temperatures was investigated. The burned coal gangue was mixed with portland cement in different proportions （ 20% - 60% ）. The pozzolanic activity of coal gangue burned and the hydration products were examined, the compressive strengths of the pastes of the mixtures were tested, and the mechanism of the reaction was discussed. The experimental results slum, that the coal gangue burned at 750 ℃ has the optimum pozzolanic activity, and the burned coal ganguc with SiO2 and Al2 O3 is in an active form. When the coal gangue burned at 750℃ is mixed into portland cement, the content of calcium hydroxide in paste is significantly reduced, while the contents of hydrated calcium silk.ate and hydrated calcium aluminate are increased accordingly, hence resulting in the improvement of the microstructure of mortar. The compressive strength of cement paste decreases with increasing the content of burncd coal gangue. The decease in strength is small in the range of 20% - 30% coal gangue substitution and significant in 30%- 60% substitution.     

Preparation, characterization and photocatalytic behavior of WO3-TiO2/Nb2O5 catalysts

TiO2/Nb2O5 photocatalyst loaded with WO3 (WO3-TiO2/Nb2O5) was prepared by a modified hydrolysis process, and characterized by X-ray diffractometry, transmission electron microscopy, Raman spectra and UV-Vis diffuse refraction spectroscopy. The photocatalytic activity of WO3-TiO2/Nb2O5 was investigated by employing splitting of water for O2 evolution. The results indicate that WO3 loading can pronouncedly improve the photocatalytic activity of TiO2/Nb2O5 by using Fe3 as an electron acceptor under UV irradiation. The optimum molar fraction of the loaded WO3 is 2%, and the largest speed of O2 evolution for 2% WO3-TiO2/Nb2O5 catalyst is 151.8 μmol/(L·h).