Objective: To investigate the effect of different processing methods on nano-Realgar for screening the best processing methods

with processed products yield

weight of the residue

particle size distribution and the contents of As2S2 and As2O3 as indicators. Method: Raw products of nano-Realgar were prepared by high-energy ball milling technology and processed by water

acid water and alkali water

then calculated the yield of processed products and the weight of residue.The average size and the morphology of particles were determined by laser scattering analyzer and scanning electron microscopy (SEM).And the contents of As2S2 and As2O3 in different samples were detected by direct iodine titration method and silver diethyl dithiocarbamate (Ag-DDC) method

respectively. Result: Yields of processed products by water

acid water and alkali water were 96.71%

95.86% and 79.08%

the weights of residue were 0.328

0.891

2.208 g.The average sizes of raw products and processed products by water

acid water and alkali water were (157.3±4.8)

(143.9±6.2)

(137.7±4.5)

(139.8±5.3) nm

contents of As2S2 of them were (94.26±1.33)%

(98.97±0.98)%

(99.58±1.45)% and (99.37±2.60)%

contents of As2O3 were (9.64±0.68)

(3.44±0.29)

(2.83±0.27)

(18.17±1.70) mg·g-1. Conclusion: These three kinds of processing methods can reduce the average particle size of raw products of nano-Realgar and improve the content of As2S2.In addition

the water and acid water method can both reduce the content of As2O3 in raw products of nano-Realgar.The acid water processing is the best.