Objective:

2

Ammonium alum is a common counterfeit of Alumen

and the processed product of ammonium alum is a common counterfeits of calcined Alumen. This paper aims to establish a method for identifying Alumen

calcined Alumen

ammonium alum and their processed products.

Method:

2

The samples were analyzed by scanning electron microscope (SEM) and X ray diffraction (XRD) in this paper.

Result:

2

Ammonium alum and Alumen showed obvious changes in morphology after processing. Both Alumen and ammonium alum showed obvious differences in morphology at ×250 and ×1 000 times microscope. Alumen presented irregular fragments

clear edge corners

smooth surface

scattered irregular small particles

occasional holes and longitudinal edges. Ammonium alum presented irregular clumps

blunt edges

not obvious edges and corners

uneven surface

scattered smaller and round-like particles. The difference in morphology was not obvious at ×250 times microscope between Alumen and ammonium alum processed products. While at ×1 000 times

the surface of calcined Alumen was uneven with coarse particles; the surface of counterfeit calcined Alumen was flat

and the coarse particle characteristics were not obvious. XRD can be used to rapidly and accurately identify the primary phase of Alumen

calcined Alumen

ammonium alum and ammonium alum processed products: KAl(SO

4

)

2

·12H

2

O

NH

4

Al(SO

4

)

2

·12H

2

O

KAl(SO

4

)

2

and NH

4

Al(SO

4

)

2

respectively

with 2

θ

angle characteristic value of 23

12

22 and 5 respectively for XRD peak.

Conclusion:

2

SEM and XRD techniques can be used for the identification of Alumen

calcined Alumen

ammonium alum and their counterfeit products.