GB/T 8151.7-2012Methods for chemical analysis of zinc concentrates - Part 7: Determination of arsenic content - Hydride generation-atomic fluorescence spectrometry and the potassium bromate titrimetric method (English PDF)

2.1 Method summary

Sample with nitric acid, sulfuric acid dissolution. 10% hydrochloric acid medium with thiourea - ascorbic acid pre-reduced arsenic, as well as masking copper, iron, silver

And other impurities in the hydride generator, arsenic is reduced to potassium borohydride as hydride with argon gas into the quartz furnace atomizer, atomic fluorescence

VIS spectrometer to measure the fluorescence intensity.

2.2 Reagents

Unless otherwise indicated in the analysis using only recognized as analytical reagent and distilled or deionized water or equivalent purity.

2.2.1

Potassium Chlorate.

2.2.2

hydrochloric acid (rho1.19g/mL).

2.2.3

nitrate (rho1.42g/mL).

2.2.4

sulfuric acid (11).

2.2.5

sulfuric acid (14).

2.2.6

hydrochloric acid (19).

2.2.7

Potassium hydroxide (5g/L).

2.2.8

Potassium hydroxide (100g/L).

2.2.9

thiourea - ascorbic acid solution (50g/L), the day of preparation.

2.2.10 potassium borohydride solution (20g/L)

Weigh 10.0g of potassium borohydride were dissolved in 500mL of potassium hydroxide solution (2.2.7), the day

Formulated.

2.2.11 arsenic standard stock solution

Weigh 0.1320g sulfuric acid was dried in a dryer trioxide (wAs2O3>=99.99%)

In 300mL beaker, add 20mL of potassium hydroxide (2.2.8), dissolved by heating, added 5mL of sulfuric acid (2.2.4), sulfuric acid (2.2.5) diluted

To 1000mL. This solution 1mL containing 100µg arsenic.

2.2.12 arsenic standard solution

Pipette 5.00mL arsenic standard stock solution (2.2.11) in 500mL volumetric flask, was added 75mL of hydrochloric acid (2.2.2), dilute with water to volume, and mix. This solution 1mL containing 1µg of arsenic.

2.3 Instrument

Atomic fluorescence spectrometer, with a special high-strength arsenic hollow cathode lamp.