| Based on the facts that the mineral resources in China is characterized by lean ore,refractory ore,bonanza,mineral intergrowth and difficult to separate,and economic development on the demand of mineral resources,it is urge and necessary to develop the methods and technologies for the effective processing and utilization of the mineral resources,especially in mineral flotation,new technology and other aspects of beneficiation reagent.In this thesis,our aim is to develop new technology for the mineral flotation and leaching for the complex and low grade minerals.1.According to the structure of the hematite ore in Tongdao Hunan,a disperse system was designed and developed to disperse the hematite ores,and the adsorption properties on the surface of quartz and iron oxide was also studied.Furthermore,the effects of different molecular weight dispersants,pH value,temperature of the solution,the size of pure silica on the adsorption performance were studied,as well as its adsorption mechanism.Compared with other dispersing agents,the dispersing agent system was applied in the selective desliming stage.Important factors which include the pH,the stirring rate,the stirring time and pulp density are explored to the dispersed system.Finally,the optimal dispersing technology is determined,which include the pulp concentration of 17.00%,pH = 9.5,stirring rate for 1200 r/min,stirring for 10 minutes.In the selective flocculation stage,it is found that the PVP selective flocculation effect is better than modified corn starch,and the water quality is little impact the flocculation-selective,breaking the traditional polymer flocculant sensitive to the water quality.Via a series of conditions processes,which include dry strong-magnetic,wet strong-magnetic,centrifugal mineral processing,selective dispersion and flocculation process and contra-flotation stage process,the optimal conditions were selected for the various stages,and proposed four different joint processes.Ultimately,the joint process of'stage of grinding-dry strong-magnetic-wet strong-magnetic-selective desliming-contra-flotation" is adopted.This process can abtained TFe of the extract above 62%,ferrous metals recovery rate of nearly 70%.So show how to explore and use the mineral in Tongdao.The research results have a significant guiding on the rational exploitation and comprehensive use of the hematite ore in Tongdao.2.The flotation process for hemimorphite ore in Shizhu Chongqing was studied by using a-nitroso-?-naphthol as activtor,octadecylamine and benzohydroxanic acid as collectors.Based on the single factor experiment,the effect of pH,the dosage of collector,activator and dispersants on the flotation process were discussed.When octadecylamine was used as the collector,the grade of zinc was up to 38.26%and recovery to 87.90%under the following optical conditions:pH:9.5,a-nitroso-?-naphthol:2×10-5 mol·L-1,octadecylamine:1200 g·t-1 and calcium lignosulphonate:1200 g·t-1.As benzohydroxanic acid,the optimal conditions were as follows:pH:9.0,?-nitroso-?-naphthol:2×10-5 mol·L-1,benzohydroxanic acid:800 g·t-1 and sodium hexametaphosphate:1000 g·t-1.The grade of zinc was 40.36%and recovery to 61.20%.This technology process was much more effective with low consumption,furthermore,increased the selectivity.The dispersion performance of the four kinds of dispersant(sodium hexametaphosphate,sodium silicate,composite dispersant and calcium lignosulphonate)was also studied.Finally,the mechanism of the reaction between the flotation reagents and the surface of mineral was explored by FTIR.The results showed thata-nitroso-?-naphthol have been adsorbed on the surface of oxidized zinc ore,and a five-ring chelate have been formed by the reaction of nitrogen and oxygen atoms in the molecular of the a-nitroso-p-naphthoi with Zn2+ on the mineral surface,which made the mineral surface hydrophobic to some extent and consequently promoted adsorption of collectors on the mineral surface.3.For the difficult smelting for ZnO,the defects and shortcomings of the acid and alkali extraction method for the extraction of Zn from hemimorphite ores,the lean hemimorphite ore was selected for the extraction of Zn.Firstly,the extraction of Zn hemimorphite ores obtained from Shizhu Chongqing was carried out by the acid and alkali extraction method,the effects of alkalinity,liquid-solid ratio,temperature and time in the process of extraction on the Zn leaching rate were studied.Based on the results,Ca(OH)2 was added into the leaching system to help the extraction of Zn from hemimorphite ores.It was founded that the addition of Ca(OH)2 was helped for the extraction of Zn from hemimorphite ores,and reduced the amount of NaOH.The optimal extraction technology by the aiddtion of Ca(OH)2 is determined.Secondly,the effects of acidity,liquid-solid ratio,temperature and time in the process of extraction on the Zn leaching rate were evaluated.The high effective Zn leaching rate was accomplished by the gradual concentration difference method,which prevent the produce of the silica sol,and accelerated the filtration time.Finally,Pilot scale test was carried out at a factory in Shizhu Chongqing,a new production line was designed and developed for the extraction of Zn from hemimorphite ores,which the process of production capacity will reach 75 tons/day,and the final products is basic zinc carbonate and zinc electrolyte. |
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