GB/T 7739.1-2019Methods for chemical analysis of gold concentrates - Part 1: Determination of gold and silver contents (English PDF)

2.1 Principle

The sample was compounded and melted to obtain lead of precious metal with appropriate quality and fragile slag. In order to recover the gold remaining in the slag,

Silver, again test the slag. Gold, silver and lead buckle are separated by ash blowing to obtain gold-silver composite grains.

The amount of gold and silver was measured.

2.2 Reagents and materials

Unless otherwise stated, only reagents and distilled water of equivalent analytical purity and water of comparable purity were used in the analysis.

2.2.1 Sodium carbonate

industrially pure, powdery.

2.2.2 Lead oxide

industrially pure, powdery. The amount of gold is < 0.02g/t, and the amount of silver is < 0.5g/t.

2.2.3 Borax

industrially pure, powdery.

2.2.4 Glass powder

particle size <= 0.18mm.

2.2.5 silicon dioxide

industrially pure, powdery.

2.2.6 Potassium nitrate

industrially pure, powdery.

2.2.7

Pure silver (mass fraction >=99.99%).

2.2.8 Covering agent (2 1)

Mix two parts of sodium carbonate with one part of borax.

2.2.10

Lead foil (mass fraction >=99.99%). thickness is about 0.1mm, the amount of gold is < 0.02g/t, and the amount of silver is < 0.5g/t.

2.2.11

Nitric acid (rho = 1.42g/mL).

2.2.12

Glacial acetic acid (rho = 1.05g/mL).

2.2.16 silver nitrate solution (10g/L)

Weigh 5.000mg of pure silver (2.2.7), put it in a 300mL beaker, and add 20mL nitric acid (2.2.14), heat at low temperature to completely dissolve, cool to room temperature, transfer to a 500mL volumetric flask, wash the beaker with nitric acid (2.2.14), and wash the solution together.

Into the volumetric flask, dilute to the mark with water and mix well. 1 mL of this solution contained 10 mg of silver.