The latest development is reviewed of process and equipment in domestic tungsten smelting industry.The process development is oriented towards energy saving and environmental protection.Guided by the market and policy,the new process and equipment would be gradually applied to further improve environment-friendly production level in tungsten smelting industry.

The main indexes of Nb2O5 physical properties and their relationship are discussed.The key indexes to study Nb2O5 physical properties are determined.The main factors affecting Nb2O5 physical properties and their change rules during preparation are analyzed.And the latest development of Nb2O5 preparation technology is introduced.

Titanium was extracted from red mud by triple circulating acid leaching,and the influences of sulfuric acid concentration,leaching temperature and reaction time on titanium recovery were investigated.The reaction controlling step was determined based on kinetic analysis of the leaching experimental data.The results show that titanium recovery reaches 82% and acid consumption is reduced by 25% under the conditions of 3-stage leaching,6mol/L sulfuric acid concentration,5∶1liquid to solid ratio,90 ℃leaching temperature and 60 min reaction time.The apparent activation energy is 21.77kJ/mol during acid leaching and the reaction is controlled by internal diffusion with a linear correlation coefficient greater than 0.98.Both sulfuric acid concentration and leaching temperature are the key factors affecting titanium recovery.

Tellurium was recovered from SbTe-containing waste catalyst by 4hagitation leaching with 2.5mol/L NaOH solution as the leaching agent under room temperature,atmospheric pressure and solid to liquid ratio 1∶5.And the leaching rate of tellurium reaches 95%.The deposition rate of tellurium is above95% under 1.5~4.0Vcell voltage and 5hdeposition with steel plate as the anode and stainless steel plate as the cathode.Finally,56.76%tellurium enriched product is obtained.

Single rare earth oxides were produced from ion-absorbed rare earth ore by the patented technology of rare earth separation of non-ammonia nitrogen and magnesium saponification extraction and fuzzy extraction separation technology.The total rare earth recovery is 94.5%.All kinds of pollutants generated in the production process of rare earth oxides were treated with effective control measures to meet emission standards.

Copper and gold were recovered from electronic and electrical waste.The adopted processes are sulfuric acid stirring leaching-electrolysis and nitric acid treatment of copper leaching residue combined with cyanide plating off the board-zinc replacement-purification with aqua regia,respectively,including the process steps of leaching,replacement,electrodeposition and precipitation.

Thermal decomposition of ammonium paramolybdate in 30~600℃air was analyzed by TG-DSC.The results show that there are three stages during weight loss of ammonium paramolybdate at 30~600℃,and weight loss tends to finish when the temperature is higher than 340℃.XRD pattern shows that the end product of thermal decomposition is pure orthorhombic molybdenum trioxide.The mechanism of thermal decomposition of ammonium paramolybdate in the air was proposed and theoretical verification was carried out.It is considered that ammonium paramolybdate only loses four crystal water molecules in the first stage of its thermal decomposition,while NH3 and H2O are lost by the molar ratio of 2∶1in the other three stages.Otherwise,through enthalpy change values of decomposition reaction in the various stages,approximate molar formation enthalpy was estimated of ammonium paramolybdate and the related decomposition products under the experimental conditions.

The behavior of Fe impurity was studied during preparation of high purity titanium by CVD.The conditions of synthesis and decomposition of ferrous halide were analyzed based on thermodynamic calculation.The results show that the optimal halogenation temperature is 800~1 000 K,and the best pyrolysis deposition temperature is 1 400~1 650 K.In the above temperature range,not only can high purity titanium be effectively produced,but also the secondary pollution caused by Fe impurity can be effectively inhibited.

Study was made on the microstructure of AlFeCrCoCu high-entropy alloy fabricated by arc remelting and its high temperature oxidation resistance and hardness at 900℃,1 000℃,1 100℃and 1 200℃.The results show that the alloy is typical dendrite with serious composition segregation,and Cu is enriched in the interdendritic phase to form FCC phase.The melting point of the alloy is about 1 380 ℃,and the interdendritic Cu-rich phase begins to melt at about 1 050 ℃.The alloy has a strong resistance to high temperature oxidation and its mass is almost unchanged until heated to about 800℃.The results from oxidation experiments show that the alloy has a strong oxidation resistance below the melting point of the interdendritic Cu-rich phase,i.e.1 050 ℃,while above this temperature alloy surface oxidation is more serious.XRD and EDS results of alloy oxidated surface show that Al3O2 film is generated on alloy surface during high temperature oxidation to prevent its further oxidation.In addition,the alloy has a strong hardness.The hardness of the oxidated alloy at 1 100 ℃ and 1 200 ℃is higher than that of the as-cast alloy.

Three-way catalyst was prepared by isovolumetric impregnation with the scattered metal In,the transition metal Ag and the rare earth metal Ce as the active components andγ-Al2O3 as the carrier.The microstructure of the catalyst was characterized by XRD,BET,SEM and N2 adsorption technology.The influence of In content on catalyst performance was also investigated.The results show that the catalyst activity can be improved after In addition resulting in AgInO2 phase appearing in its XRD pattern.However,the catalyst activity gradually decreases with the increase of In content.The results from BET and SEM show that the increase of In content causes aggregation of the active ingredients to reduce their dispersion degree and decrease of the specific surface area of the catalyst to reduce its catalytic activity.In-Ag-Ce-O/γ-Al2O3 catalyst has the strongest three-way catalytic activity when its active ingredient In content is 2%.