The rice industry in Wuchang City has the advantages of improved varieties,well-known brands,technology management practices,and also the disadvantages of low coverage of farmer associations,single product variety,low...The rice industry in Wuchang City has the advantages of improved varieties,well-known brands,technology management practices,and also the disadvantages of low coverage of farmer associations,single product variety,low level of deep processing and inefficient quality control.In this article,we analyze the current situation of the rice industry in Wuchang City,and point out some problems in the circulation system of Wuchang rice.Finally,we put forth the following recommendations:supporting the building of farmer associations and strengthening the farmers'bargaining power and status in the market;supporting the leading enterprises to develop many rice product varieties and improve the deep processing capacity;further improving the support service system.展开更多
The leaching efficiency(LE) of ion adsorption rare earth(IARE) by the sulfate and chloride of ammonium,magnesium and aluminum were comparatively determined using column leaching method. It is found that at equal equiv...The leaching efficiency(LE) of ion adsorption rare earth(IARE) by the sulfate and chloride of ammonium,magnesium and aluminum were comparatively determined using column leaching method. It is found that at equal equivalent concentration of cation, the LE of IARE by aluminum sulfate is the highest, and the zeta potential of clay mineral particles in the tailing is near to zero, which means a lower risk of landslide and pollutant emission. Furthermore, the optimum concentration of aluminum sulfate is determined to be0.02 mol/L, which is much lower than that of ammonium sulfate and magnesium sulfate. To reduce the production cost and environmental impact, we proposed a multi-stage leaching process, which was firstly leaching with ammonium sulfate and then with aluminum sulfate, following by water washing and lime neutralizing. With the ratio of ammonium sulfate to aluminum sulfate varying from 1:0 to 0.5:0.5, the residual ammonium in tailing decreases from 11.2% to 0.6%, however, the LE of RE shows an optimum value at 0.8:0.2. By neutralizing the pH of tailing with lime water to over 6, the ion concentration in water rinsing solution can meet the requirement for water discharge. At the same time, the zeta potential of clay particles is found to be around-5 mV, means a relatively lower risk of landslide. These facts indicate that the LE of IARE can be increased and the danger caused by tailings landslides and pollutant emissions can be reduced by replacing ammonium sulfate with aluminum sulfate as leaching reagent.展开更多
文摘The rice industry in Wuchang City has the advantages of improved varieties,well-known brands,technology management practices,and also the disadvantages of low coverage of farmer associations,single product variety,low level of deep processing and inefficient quality control.In this article,we analyze the current situation of the rice industry in Wuchang City,and point out some problems in the circulation system of Wuchang rice.Finally,we put forth the following recommendations:supporting the building of farmer associations and strengthening the farmers'bargaining power and status in the market;supporting the leading enterprises to develop many rice product varieties and improve the deep processing capacity;further improving the support service system.
基金supported by the National Natural Science Foundation of China(51864033,21161014,51274123)the National Key Basic Research Development Program of China(2012CBA01204)
文摘The leaching efficiency(LE) of ion adsorption rare earth(IARE) by the sulfate and chloride of ammonium,magnesium and aluminum were comparatively determined using column leaching method. It is found that at equal equivalent concentration of cation, the LE of IARE by aluminum sulfate is the highest, and the zeta potential of clay mineral particles in the tailing is near to zero, which means a lower risk of landslide and pollutant emission. Furthermore, the optimum concentration of aluminum sulfate is determined to be0.02 mol/L, which is much lower than that of ammonium sulfate and magnesium sulfate. To reduce the production cost and environmental impact, we proposed a multi-stage leaching process, which was firstly leaching with ammonium sulfate and then with aluminum sulfate, following by water washing and lime neutralizing. With the ratio of ammonium sulfate to aluminum sulfate varying from 1:0 to 0.5:0.5, the residual ammonium in tailing decreases from 11.2% to 0.6%, however, the LE of RE shows an optimum value at 0.8:0.2. By neutralizing the pH of tailing with lime water to over 6, the ion concentration in water rinsing solution can meet the requirement for water discharge. At the same time, the zeta potential of clay particles is found to be around-5 mV, means a relatively lower risk of landslide. These facts indicate that the LE of IARE can be increased and the danger caused by tailings landslides and pollutant emissions can be reduced by replacing ammonium sulfate with aluminum sulfate as leaching reagent.
