CN1945273A

CN1945273A - Method for detecting high content gold by fire assaying

Info

Publication number: CN1945273A
Application number: CN 200610124667
Authority: CN
Inventors: 刘昌勇; 梁亚群; 罗智; 汪廷龙; 陈丽清; 邵海青; 张黎明
Original assignee: JIANGXI COPPER CORP GUIYE BRANCH
Current assignee: JIANGXI COPPER CORP GUIYE BRANCH
Priority date: 2006-09-28
Filing date: 2006-09-28
Publication date: 2007-04-11
Anticipated expiration: 2026-09-28
Also published as: CN100529723C

Abstract

The fire assaying method for detecting high content gold includes the following steps: rolling the sample into foil, adding 2.5 times Ag and Cu in 50 mg, wrapping in lead foil and forming into ball; setting the tested sample and the gold standard in cupel and cupelling; tapping to form oblate, rolling into sheet, winding into hollow reels and setting into parting basket; heating in water bath for parting for three times, stoving in a stove for 15 min, setting in ceramic crucible, annealing at 800 deg.c for 5 min, weighing and calculating. The fire assaying method of the present invention has high accuracy.

Description

A kind of method of detecting high content gold by fire assaying

Technical field

The present invention relates to the assay method of the main amount of gold in the ingot, especially a kind of method of detecting high content gold by fire assaying.

Background technology

The analytical approach of gold mainly contains three kinds in the current mensuration ingot: fire assaying, spectrum decrement determination method and chemical decrement determination method.Spectrum decrement determination method and chemical decrement determination method all only are applicable to measures the ingot contain Au＞99.95%, for Au＜99.95% because impurity content height, impurity element kind are measured not congruent reason, cause the accuracy variation of measurement result and inapplicable.And fire assaying is directly to measure main amount gold, be not subjected to the impurity quantitative limitation, fire assaying can be removed impurity element effectively because of it, thereby the accuracy of measurement result is higher, but the national standard method GB/T 15249-1994 of present fiery ensaying gravimetric determination gold amount, because of its to the analytic process and the reasons such as standard sample line purity is not enough that adopt, make its accuracy and precision all not reach optimum, stipulate in the method that Au＞99.5% franchise is 0.0002%, in fact be difficult to realize, with international most advanced level 99.5%＜Au＜99.95% franchise be 0.00015%, Au＞99.95% franchise is 0.00005%, and tangible gap is arranged.

Summary of the invention

Purpose of the present invention just provides a kind of method of detecting high content gold by fire assaying, and this method can improve the accuracy and the precision of measurement result.

The method of detecting high content gold by fire assaying of the present invention is:

1, sample surfaces is cleaned out, ground flakiness, replace weighing testing sample and goldstandard, put into ready lead foil, in every part of goldstandard and testing sample, add the fine silver and the 50mg fine copper of 2.5 times of gold amounts, sheet lead is rolled into sphere with balance;

2, cupel is put into 950 ± 10 ℃ cupel(lation) furnace preheating 30 minutes, then testing sample and goldstandard are put into cupel in order, close fire door, treat test portion all after the fusing, the blow-on door carries out ash and blows slightly, until grey blowing bundle;

3, close grain, rap and close a both sides, make it to be oblate, brush away attachment, in 800 ℃ of annealing 5 minutes, taking-up will be closed grain and be ground flakiness, gold and silver be closed a thin slice again and be rolled into two reverse coreless rolls, put into parting basket successively by the ash mode of blowing, and use hot wash;

4, carry out parting three times with water-bath heating, when nitric acid was heated to 80-85 ℃ in 1: 1, parting basket put into begins to carry out parting, parting 40 minutes takes out with after the hot wash; Put into 2: 1 nitric acid partings again 30 minutes, and took out with after the hot wash; Put into 2: 1 nitric acid partings again 30 minutes; Taking-up with hot wash after, parting basket is put into 105 ℃ baking oven baking 15 minutes, take out, with tweezers the gold volume is moved in the porcelain crucible, in 800 ℃ of annealing 5 minutes, take out cooling, on microbalance, weigh, calculate.

The calculating of analysis result and statement:

The percentage composition of gold is calculated as follows:

Au (%) = \frac{m_{1} - (m_{3} - m_{4} \cdot D)}{m_{2}} \times 100

In the formula: m ₁---measure test portion gold volume quality, g;

m ₂---the quality of test portion, g;

m ₃---measurement standard gold volume quality, g;

m ₄---the quality of standard, g;

D---the percentage composition of proof gold standard specimen gold

In said method, goldstandard is done standard with the High Purity Gold of gold content＞99.999% and is used, the fine copper that adds is blown over the fusing point that reduces gold in the journey at ash, prevents golden oxidation, can avoid gold and silver to close grain adsorbed gas in temperature-fall period and discharge too fast and occur splashing and make the gold loss.

Adopted exclusive protective agent copper in the method for detecting high content gold by fire assaying of the present invention; and to all details of operation all in addition optimization and standard; can reach the pin-point accuracy high precision; franchise can be controlled the world level of advancing; 99.5%＜Au＜99.95% franchise is 0.00015%, and Au＞99.95% franchise is 0.00005%.

Embodiment

It is 99.85% that two ingot prediction gold contents are arranged.

Sample surfaces is cleaned out, grind flakiness again, replace weighing with balance and treat each four parts of test samples and five parts of goldstandards (Au＞99.999%), accurately to 0.0000001g, goldstandard sample amount is controlled in 0.5000000～0.5005000g, and testing sample sample amount is controlled in 0.5005000～0.5010000g, puts into ready lead foil, the lead foil general assembly (TW) is about in 11.6 ± 0.1g, finishes in 1 hour.Every part of goldstandard with treat to add in the test sample 1.250 ± 0.001g fine silver and 50mg fine copper, sheet lead is rolled into sphere.Cupel is put into 950 ± 10 ℃ of cupel(lation) furnace preheatings 30 minutes, will treat that then test sample and goldstandard put into cupel in order, close fire door, treat test portion all after the fusing, the blow-on door carries out ash and blows slightly, until grey blowing bundle.Take out gold and silver and close grain, rap and close a both sides, make it to be oblate, brush away attachment.800 ℃ of annealing 5 minutes, taking-up will be closed grain and be ground into the length and width of 0.12 ± 0.02mm, thick basically identical thin slice, annealed 5 minutes at 800 ℃, the gold and silver after the annealing is closed be rolled into two reverse coreless rolls after a thin slice cools off, put into parting basket successively by the ash mode of blowing.Parting three times, for the first time parting: parting basket put into be preheated to 85 ℃ 1: 1 nitric acid with water-bath and begin parting, parting 40 minutes takes out the parting basket hot wash; Parting for the second time: the parting basket after will wash was placed in the water-bath in enough long 2: 1 nitric acid of preheating parting 30 minutes, the hot wash of taking-up parting basket; Parting is from multiple operation for the second time for the third time.The baking oven that parting basket after washing is put into 105 ℃ dried by the fire 15 minutes, took out, and the gold volume is taken out from parting basket put into porcelain crucible successively, annealed 5 minutes in 800 ℃ cupel(lation) furnace then, weighed on microbalance and calculate in taking-up cooling back.

Claims

1, a kind of method of detecting high content gold by fire assaying, it is characterized in that: it may further comprise the steps:

(1), sample surfaces is cleaned out, grind flakiness, replace weighing testing sample and goldstandard, put into ready lead foil, in every part of goldstandard and testing sample, add fine silver and the 50mg fine copper that 2.5 times of gold are measured, sheet lead is rolled into sphere with balance;

(2), cupel is put into 950 ± 10 ℃ cupel(lation) furnace preheating 30 minutes, then testing sample and goldstandard are put into cupel in order, close fire door, treat test portion all after the fusing, the blow-on door carries out ash and blows slightly, until grey blowing bundle;

(3), close grain, rap and close a both sides, make it to be oblate, brush away attachment, in 800 ℃ of annealing 5 minutes, taking-up will be closed grain and be ground flakiness, again gold and silver is closed a thin slice and be rolled into two reverse coreless rolls, put into parting basket successively by the ash mode of blowing, and use hot wash;

(4), carry out parting three times, when nitric acid was heated to 80-85 ℃ in 1: 1, parting basket put into begins to carry out parting, parting 40 minutes takes out with after the hot wash with water-bath heating; Put into 2: 1 nitric acid partings again 30 minutes, and took out with after the hot wash; Put into 2: 1 nitric acid partings again 30 minutes; Taking-up with hot wash after, parting basket is put into 105 ℃ baking oven baking 15 minutes, take out, with tweezers the gold volume is moved in the porcelain crucible, in 800 ℃ of annealing 5 minutes, take out cooling, on microbalance, weigh.

2, the method for detecting high content gold by fire assaying according to claim 1 is characterized in that: described goldstandard is done standard with the High Purity Gold of gold content＞99.999%.