GB/T 5120.3-1995 Chemical analysis methods for crude copper - Determination of gold and silver content
Some standard content:
National Standard of the People's Republic of China
Methods for chemical analysis of blister copper--Determination of gold and silver contentsSubject and scope of application
This standard specifies the method for determining the gold and silver content in blister copper. GB/T 5120.3.. 1995
Replaces GB 5120.2
This standard applies to the determination of gold and silver content in blister copper. Determination range: gold ≥ 0.5g/t silver 20g/t. 2 Reference standards
GB1.4 Guidelines for standardization work Provisions for the preparation of chemical analysis method standards GB1467 General principles and general provisions for chemical analysis method standards for metallurgical products 3 Summary of methods
The sample is dissolved in sulfuric acid, and the gold and silver precipitates obtained after filtering and removing copper are ashed, batched, and melted to obtain the desired lead buckle. The lead buckle is blown and the gold and silver content is determined by gravimetric method. The correction method is to add pure copper as the matrix and pure gold and pure silver together with the test sample, and make corrections according to the yield or ash dish and slag melting method.
4 Reagents
Soda: industrial pure, powder.
Lead oxide: industrial pure, powder (gold content ≤0.05ug/g: silver ≤5g/g). 4.2
4.3 Borax: powder.
Starch: industrial pure, powder.
Silicon dioxide: industrial pure, powder.
Sodium chloride: industrial pure, powder.
Pure gold: 99.99%.
Pure silver: 99.99%.
Pure copper: 99.95%.
Sulfuric acid (o1. 84 g/mI.).
Nitric acid (1+1).
Nitric acid (1+7)
Mercuric sulfate solution (23g/L).
Sodium chloride solution (10g/L).
Glacial acetic acid (1+3). Www.bzxZ.net
5 Instruments and equipment
5.1 Balance
Approved by the State Administration of Technical Supervision on October 17, 1995 and implemented on March 1, 1996
5.1.1 Ultra-micro balance: sensitivity 0.001mg. 5.1.2 Micro balance: sensitivity 0.01mg.
5.1.3 Analytical balance: sensitivity 10img.
5.1.4 Upper III balance: sensitivity 1g.
5.2 Assay furnace,
5.3 High temperature electric furnace plate,
5.4 Electric heating plate,
5.5 Ash III machine.
5.6 Porcelain glass: low type, 30ml
GB/T 5120.3—1995
5.7 Clay crucible: height 120mm, upper outer diameter 90mm, lower outer diameter 50mm5.8 Beaker: high type. 800ml.g
5.9 Ash III: height 30mm, upper inner diameter 35mm, lower outer diameter 40mm. Take out one part of horse, cattle or sheep ashes and one part of 425# cement with 1 spoon, add appropriate amount of water, stir and press on the ash dish machine, and keep it for three months. 6 Analysis steps
6.1 Test material
According to the mass ratio after screening, call it 20g sample (when the gold content is less than 10g/t, call it 40g sample), accurate to 0.01g, conduct two tests independently and take the average value. 6.2 Blank test
6.2.1 Blank test of lead oxide and pure copper used in correction by method A (i.e. "correction method with pure gold and pure silver"): weigh 20g of pure copper respectively, each part, accurate to 0.01g. The following is carried out according to 6.3.1 to 6.3.5 6.2.2 Blank test of lead oxide used in correction by method B (i.e., "ash III and slag melting correction method"): weigh 25g soda, 120g lead oxide, 10g borax, 25g silicon dioxide, and 3% starch in a clay pot. After stirring, cover with 10mm thick sodium chloride, and proceed as in 6.3.3 to 6.3.5.
6.3 Determination
6.3.1 Wet treatment
6.3.1.1 Place the sample (6.1) in a beaker, and according to the sample conditions listed in Table 1, add the corresponding co-solvent and solvent in order (each reagent must be mixed evenly). Table 1
Sample conditions
Au:10 g/t
Ai~ g/1
Aiding agent addition amount, ml
Acid (4.12)
Mercuric sulfate solution
Solvent addition amount.m!
6.3.1.2 Cover the beaker, steam on a high-temperature electric stove until it becomes a paste, remove it, and cool it to room temperature. Add 300ml of water (for samples with a gold content of less than 10g/, add 500ml of water) and 20ml of sodium fluoride solution, add a small amount of filter paper pulp, wash the beaker wall with water, boil for about 5 minutes, remove the shaking beaker, wash the beaker and the beaker wall with warm water, and filter it with medium-speed quantitative filter paper after it cools slightly. 6.3.1.3 Transfer all the precipitate to the filter paper. Wash the precipitate with warm water until there is no blue color. Put the filter paper on the glass rod and the cup wall together with 184
GB/T 5120.3-1995
Put the filter paper with the precipitate in a clay crucible and put it in the gold assay furnace. Raise the temperature from room temperature to about 500°C (for ash treatment until carbonization is complete. 6.3.2 Ingredients
Cool the clay crucible containing the ash to room temperature, add 20g soda, 60g lead oxide, 7g borax, 7g silicon dioxide, 3g starch stirring spoon, and cover slightly with 10mm thick sodium chloride.
6.3.3 Melting
Put the prepared clay crucible in a gold assay furnace at 800°C and heat it at 30-4 Heat to 1100℃ within 0min (keep warm for (min (melting time is 45～55min) and take out of the furnace. Pour the molten material into the preheated and oiled cast iron mold. After cooling, hammer the lead III into a square shape and collect the slag into the original crucible for standby use.
6.3.4 Ash blowing
6.3.4.1 Place the lead in the ash stream preheated for 20min in the assay furnace at 900℃, close the furnace door, and open the furnace door slightly after the luster film on the surface of the lead liquid disappears (shelling), so that the furnace temperature drops to 840～860℃ (for ash blowing. When the composite particles appear to flash, the carbon blowing is over, move the mass to the furnace door, and put it into the ash tray after cooling slightly. 6.3.4.2 Use tweezers to remove the gold test particles from the ash, place them in a porcelain crucible, add 10-15 ml of glacial acetic acid, boil 3-5 ml on a hot plate, remove them, wash them three times with warm water, and remove the washing liquid. Dry the gold and silver particles retained in the porcelain crucible on a high-temperature electric furnace, remove them, cool them to room temperature and weigh them (accurate to 0.01 mg). 6.3.5 Gold Separation
Pound the weighed gold and silver particles into thin slices on a small steel anvil, put them in a porcelain crucible, add 5-7 ml of hot nitric acid (4.12), and place them on a low-temperature electric hot plate to warm the gold separation. When the volume evaporates to 1-2 ml, add another 5-7 ml of hot nitric acid (4.11). Evaporate to about 2 ml, remove them, cool them and wash them three times with hot water. Place the porcelain crucible containing the gold particles on a dry high-temperature electric furnace plate to dry and burn them for 5 minutes, remove them, cool them to a low temperature, and weigh them (accurate to 0.001 mg).
6.3.6 Correction
6.3.6.1 Correction method
Method A: Weigh the same amount of pure copper as the sample, and add the same amount of pure gold and pure silver as contained in the sample. The following is carried out according to 6.3.1-6.3.5, calculate the same yield of pure gold and pure silver and make corrections. Method B: After crushing the reserved ash dish and slag, put them in the original clay pot, add 20g soda, 30g lead oxide, 20g borax, 10g catalytic dioxide, 4g starch, stir, and cover with 10mm thick sodium chloride. The following is carried out according to 6.3.3~6.3.5, 6.3.6.2 Correction range
When the gold amount measured is greater than or equal to 3.0g/t or the silver amount is greater than or equal to 50/t, start correction. If the measured gold content is equal to 50g/t or the silver content is equal to 1000g/t, the B method needs to be corrected twice. 7 Expression of analysis results
7.1 When the A method is used for correction, the gold and silver contents are calculated according to formulas (1) and (2) respectively: Au(g/t) =\)m × 100
Ag(g/t) --
formula; m—-the amount of gold measured without correction, mg; - m=㎡s × 10%
m2·the blank amount of gold in the lead oxide used for batching without correction, mg; the blank amount of silver in the lead oxide used for batching without correction, mg; ms
m.--the total amount of gold and silver particles measured when corrected. mg; m.
Quality test of sample:
Recovery rate of gold, %;
k——Recovery rate of silver, %.
hk is calculated according to formula (3) and (4) respectively:
GB/T 5120.3---1995
m- ms × 100
(%)
ka(%) mm=me × 100
Wherein: ms--blank amount of gold in lead oxide and pure copper used in recovery test, mg; me--blank amount of silver in lead oxide and pure copper used in recovery test, mg; amount of gold measured in recovery test, mg; amount of gold added in recovery test, mg; amount of gold-silver particles measured in recovery test, mg; amount of silver added in recovery test, mg. 7.2 When using method B for correction, calculate the gold and silver contents according to formulas (5) and (6) respectively: m+m+mz=m×103
Au(g/t)=
Ag(g/t) =
Where: ml
m) + (m15.- m1) + (m1s = mz) m14 × 103...mn
Amount of gold measured before correction, mg;
Amount of gold measured at the first correction, mg;Amount of gold measured at the second correction, mg;Blank amount of gold in the total amount of lead oxide used in the batching before correction and correction, mg;The total amount of gold and silver particles measured before correction, mg;The total amount of gold and silver particles measured at the first correction, mg:The total amount of gold and silver particles measured at the second correction, mg;m-Blank amount of silver in the total amount of lead oxide used in the batching before correction and correction, mg;m
Mass of the sample, name.
The amount of gold obtained is expressed to the first decimal place; the amount of silver is expressed to the integer place8Allowable difference
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0. 5~~1. 2
1. 2~5. 0
50~~100
(5)
(6)
>5. 0~10. 0
> 10. 0~~15. 0
~ 15. 0~20. 0
20. 0-~ 30. 0
230. 0~40. 0
>40. 0~80. 0
280. 0~~ 120. 0
>120. 0~180. 0
Additional instructions:
GB/T 5120. 3 --
：1995
Continued Table 2
This standard is proposed by China National Nonferrous Metals Industry Corporation. This standard is revised by Dazhi Nonferrous Metals Corporation. This standard is revised by Dazhi Nonferrous Metals Corporation. The main editors of this standard are Chen Tianshui and Feng Congxin. Silver
100～350
350～500
>500～700
≥700~-1 000
1 000~1 500
>1 500~2 000
>2 000~3 000
>3 000~4 000
>1 000
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