Abstract:

The aims are to study the production of microelement fertilizer using zinc ash waste from hot dipped galvanizing plant from the perspective of solid waste resource utilization, to change waste into valuables and to develop the recycle economy. The zinc ash waste from hot dipped galvanizing plant was used as material in this study. Inorganic acid and a mixture of inorganic acid and organic acid were used to extract zinc from zinc ash to prepare liquid organic zinc fertilizer. ICP-OES was used to determine zinc concentration of the liquid. The results showed that relatively small sample weighing error was found under large sample weighing amount and high concentration of acid, and good result was obtained when the sample weighing amount of zinc was 5-10 g. Better effect was achieved with the mixture of inorganic acid and organic acid compare to that of single acid. The best dissolving effect of zinc ash was gained by the mixture of inorganic acid and organic acid. The extract of zinc ash by mixing acids was used to treat seeds of peanut, soybean and purple maize. The germinating rate of seeds was increased at low concentration of zinc (1.5 mg/L), while high concentration of zinc (6.5 mg/L) inhibited the germinating rate and all seeds did not germinate at the concentration of 45 mg/L. The low concentration of zinc extract could promote seedlings’ growth but high concentration had an inhibition effect. When the concentration of zinc was 85 mg/L, there was a reduction of purple maize biomass of 80% compared to that of the control, but the effect on soybean growth was small. It is concluded that a mixture of inorganic acid and organic acid can be used to make liquid organic zinc fertilizer which can solve the problems of environmental pollution caused by zinc ash waste and soil zinc deficiency, and promote crop growth.

Key words: hot dipped galvanizing zinc, zinc ash, organic zinc fertilizer, liquid fertilizer, soybean