Review of tungsten resource reserves,tungsten concentrate production and tungsten beneficiation technology in China

Tungsten is a strategic metal that is widely used in various fields such as electron communication,aeronautics and astronautics,materials and chemical engineering,due to its special properties.China has the largest reserves of tungsten resources and the largest output of tungsten concentrate in the world,and plays a decisive role in the world tungsten market.In this work,firstly,the reserves and distribution characteristics of tungsten resources in China were summarized,and the production situation of tungsten concentrate in China was reviewed.Based on the gross domestic product per capita(GDP/capita),five different annual GDP growth rates were used to estimate China’s tungsten concentrate production in the future.The estimation results suggested that if China’s economy continues to grow at the current rate,the accumulative production of tungsten concentrate will exceed current reserves by approximately 2032.Then,from the aspects of process flow,beneficiation equipment and flotation reagents,the beneficiation technology development of different types of tungsten ore in China was also reviewed,including wolframite,scheelite and tungsten-bearing slime.Finally,taking several representative tungsten mines in China as examples,the classic beneficiation technology of different types of tungsten ores was elucidated in detail.Meanwhile,the development direction of tungsten beneficiation technology in the future was put forward,which was of great significance to maintain the superiority of tungsten resources in China.

Synergistic depression mechanism of zinc sulfate and sodium dimethyl dithiocarbamate on sphalerite in Pb−Zn flotation system

The depression mechanism of zinc sulfate(ZnSO4)and sodium dimethyl dithiocarbamate(DMDC)as the combined depressant on sphalerite was investigated by micro-flotation experiments,ion complexing tests,contact angle tests and X-ray photoelectron spectroscopy(XPS)analysis.The micro-flotation tests revealed that ZnSO4+DMDC had a better selective depression effect on sphalerite than using single ZnSO4 or DMDC.Ion complexing tests confirmed that DMDC had a strong complexing capacity with lead ions or hydroxy complexes.Contact angle tests illustrated that ZnSO4+DMDC makes the sphalerite surface more hydrophilic than ZnSO4 or DMDC.XPS analysis indicated that the combined depressant could prevent collector adsorbing on the Pb-activated sphalerite surface by a competitive adsorption method,while the combined depressant and collector were co-adsorbed on galena surface.

Selective depression of copper-activated sphalerite by polyaspartic acid during chalcopyrite flotation

Environmentally friendly flotation reagent,polyaspartic acid(PAPA),was tested as a potential selective depressant in the flotation separation of chalcopyrite and Cu-activated sphalerite.The depression mechanism of PAPA was revealed by contact angle measurements,Zeta potential measurements,Fourier transform infrared spectroscopy(FT-IR)analysis and inductively coupled plasma(ICP)measurement.The micro-flotation tests with single minerals showed that PAPA selectively depressed Cu-activated sphalerite,while chalcopyrite remained floatable.Moreover,a concentrate containing 31.40%Cu with a recovery of 92.43%was obtained in flotation tests of artificially mixed minerals.Results of contact angle measurements,Zeta potential measurements and FT-IR spectrum revealed that PAPA exerted a much stronger adsorption on Cu-activated sphalerite surface than on chalcopyrite surface,preventing the further adsorption of sodium diethyl dithiocarbamate(DDTC)on its surface.ICP measurements indicated that PAPA had an excellent complexing ability with Cu^(2+)in flotation pulp,weakening the activation of Cu species on sphalerite surface and producing selective depression.

Selective depression mechanism of combination of lime and sodium humate on arsenopyrite in flotation separation of Zn-As bulk concentrate

Lime(CaO)and sodium humate(NaHA)were used as the combined depressant for arsenopyrite pre-treated by CuSO_(4) and butyl xanthate.Micro-flotation tests show that the combined depressant CaO and NaHA achieved the selective depression of arsenopyrite.Closed-circuit lab-scale test results indicate that the synergistic effect of CaO+NaHA achieved a satisfactory flotation separation of sphalerite and arsenopyrite,for which the Zn grade and recovery of Zn concentrate were 51.21%and 92.21%,respectively.Contact angle measurements,adsorption amount measurements and X-ray photoelectron spectroscopy analysis indicate that the dissolved calcium species(mainly as Ca(2+))were adsorbed on the mineral surfaces,thereby promoting NaHA adsorption.Moreover,the surface of the arsenopyrite absorbed more amount of calcium species and NaHA than that of the sphalerite,thereby accounting for the strong hydrophilic surface of arsenopyrite.The adsorption of NaHA on arsenopyrite was mainly chemical adsorption through its carboxyl groups and Ca atoms,whereas that on sphalerite surface was relatively weak.