CN103018191A

CN103018191A - Analytic method of trace gold contained in composition brass

Info

Publication number: CN103018191A
Application number: CN201210509682XA
Authority: CN
Inventors: 肖红新; 庄艾春; 唐维学; 赖心
Original assignee: Guangzhou Research Institute of Non Ferrous Metals
Current assignee: Guangzhou Research Institute of Non Ferrous Metals
Priority date: 2012-12-04
Filing date: 2012-12-04
Publication date: 2013-04-03

Abstract

The invention discloses an analytic method of trace gold contained in composition brass. The analytic method of the trace gold contained in the composition brass is characterized by comprising the following steps of: grinding a sample to be powdery, weighing 1-10 grams, placing into a beaker, and adding a nitric acid solution at the volume ratio of 50%; after reaction, heating, and boiling; dissolving during micro-boiling for about 10 minutes, and taking out for cooling; filtering through a quantitative low-speed filter paper, cleaning the beaker by using deionized water, and totally transferring cleaning liquid to a filter funnel; then cleaning depositions for three times by using the deionized water, and transferring the filter paper and filter residues together into the beaker used for originally dissolving the sample; adding aqua regia, and heating; dissolving during micro-boiling till the volume of the solution is about 5-10mL, and taking out for cooling; carrying out dry filtering by using a volumetric flask with the constant volume of 25-1000mL and a core funnel; measuring the light absorbance of filter liquor by using an air-acetylene flame atomic absorption spectrophotometer; and computing the mass concentration of the gold according to a standard working curve method. The method disclosed by the invention has the advantages of ideal separation effect, accurate analytic result, good reproducibility and easiness and fastness for operation; and compared with the traditional fire assay, the method has the advantages of cost conservation, equipment, namely a high-temperature furnace, a cupellation furnace, and the like, conservation, lead pollution prevention and environment friendliness.

Description

The analytical approach of trace gold in a kind of composition brass

Technical field

The present invention relates to a kind of chemical analysis method, particularly a kind of chemical analysis method of minute amount of noble metal elements.

Background technology

Composition brass is that copper-bearing waste material forms through pyrometallurgical smelting.Copper removal is outside the main body composition, also comprises a large amount of other metals, as: iron, lead, nickel, tin etc., also contain the noble metals such as trace gold, palladium, silver.Because noble metal is expensive, so gold is the important valuation element of composition brass trade, its analysis result also is one of foundation of estimating the metallurgical technology recovery, therefore it is significant to measure accurately and rapidly gold content.Measure at present classical way or the plumbous fire assaying of gold.National standard YS/T521.3-2006 is generally adopted in the detection of the gold in the blister copper, and its principle is exactly with metallurgical principles and the process application a kind of ancient and classical method to analytical chemistry.This method is to decompose sample and enriching noble metals by solid fluxing agent under the effect of high temperature, the molten lead that is reduced has good dissolubility to noble metal, owing to forming the plumbous button of alloy than sinking to crucible bottom under great, base metal and flux play chemical combination and form slag, slag proportion is little, float over above the crucible, thereby with the noble metal separation and concentration.Plumbous under hot conditions, easily be oxidized to massicot, easily permeate in the magnesia cupel, and noble metal not can, noble metal is separated with lead, obtain noble metal and close grain, select again proper method to measure respectively.Need to use so a lot of solid fluxing agents, and long flow path, the analysis cost expense is high, labour intensity is large, produces a large amount of lead steams when ash blows simultaneously, easily causes lead contamination.

Summary of the invention

For fear of using plumbous fiery Fire Assay Concentration gold, a kind of accuracy that can guarantee testing result is proposed, flow process is short, the analytical approach of saving cost, environmental protection and minimizing labour intensity.

Technical scheme of the present invention is that bits shape composition brass sample is ground into powder, and takes by weighing 1 ~ 10 and restrains in the 200mL beaker, slowly adds volume ratio 50% salpeter solution 50 ~ 100mL; Behind the question response, heating is boiled, and little boil-off 10min that terminates an agreement takes off cooling; With quantitative Filter paper filtering at a slow speed, use the washed with de-ionized water beaker, the washing lotion total transfer precipitates three times with washed with de-ionized water to pan again, and filter paper changes in the 200mL beaker of original dissolution sample together with filter residue, adding 20 ~ 40mL chloroazotic acid (hydrochloric acid: nitric acid=3:1), heating, little boiling is dissolved to liquor capacity approximately during 5 ~ 10mL, takes off cooling, constant volume 25 ~ 1000mL volumetric flask, sand core funnel are done and are filtered.With the absorbance of Air-acetylene Flame atomic absorption spectrometry filtrate, calculate the mass concentration of gold according to the standard working curve method.

The condition of atomic absorption spectrometry gold is: detect wavelength 242.8nm, and burning height 6mm, slit width 0.4nm, lamp current 3mA, acetylene flow 1.0L/min, air mass flow 7.0L/min, flame pattern are the oxidisability blue flame.

Standard working curve is drawn: get goldstandard stock solution 0,2.00,4.00,6.00,8.00,10.00mL in one group of 100mL volumetric flask, each adds 5mL hydrochloric acid, water constant volume, mixing, in instrument its absorbance of lower measurement that imposes a condition, by the computer drawing working curve.

Sample tests: sample solution is measured absorbance under the same instruments condition, check in gold concentration at working curve, gold content in the calculation sample.

Embodiment

Below in conjunction with example the present invention is further elaborated.The sample of implementing is composition brass, forms copper ingot by all kinds of copper scraps by pyrometallurgical smelting, and copper ingot is made copper scale by mechanical sampling, and copper scale grinds by mechanical sample grinding machine and makes copper powder, and copper powder sieves through division and makes composition brass sample to be analyzed.Choose two different samples, be respectively No. 1 sample and No. 2 samples, each embodiment measures two samples respectively once according to identical method.

Embodiment 1: take by weighing approximately 1 gram sample slowly adds volume ratio 50% salpeter solution 50mL in the 200mL beaker.Behind vigorous reaction, place to heat on the low temp. electric hot plate and boil, little boil-off 10min that terminates an agreement takes off cooling.With quantitative Filter paper filtering at a slow speed, use the washed with de-ionized water beaker, the washing lotion total transfer precipitates three times with washed with de-ionized water to pan again, after having filtered, filter paper changes in the original molten sample beaker together with precipitation, adds the 20mL chloroazotic acid, continues to be placed on the low temp. electric hot plate and heats, little boiling is dissolved to liquor capacity approximately during 5 ~ 10mL, take off cooling, constant volume 100mL volumetric flask, sand core funnel are done and are filtered.Filtrate with its absorbance of Air-acetylene Flame atomic absorption spectrometry, is calculated the mass concentration of gold as detecting liquid according to the standard working curve method.

Embodiment 2: take by weighing approximately 5 gram samples slowly add volume ratio 50% salpeter solution 80mL in the 200mL beaker.Behind vigorous reaction, place to heat on the low temp. electric hot plate and boil, little boil-off 10min that terminates an agreement takes off cooling.With quantitative Filter paper filtering at a slow speed, use the washed with de-ionized water beaker, the washing lotion total transfer precipitates three times with washed with de-ionized water to pan again, filter complete, filter paper changes in the original molten sample beaker together with precipitation, adds the 30mL chloroazotic acid, continues to be placed on the low temp. electric hot plate and heats, little boiling is dissolved to liquor capacity approximately during 5 ~ 10mL, take off cooling, constant volume 100mL volumetric flask, sand core funnel are done and are filtered.Filtrate is calculated golden mass concentration as detecting liquid with its absorbance of Air-acetylene Flame atomic absorption spectrometry according to the standard working curve method.

Embodiment 3: take by weighing approximately 10 gram samples slowly add volume ratio 50% salpeter solution 100mL in the 200mL beaker.Behind vigorous reaction, place to heat on the low temp. electric hot plate and boil, little boil-off 10min that terminates an agreement takes off cooling.With quantitative Filter paper filtering at a slow speed, use the washed with de-ionized water beaker, the washing lotion total transfer precipitates three times with washed with de-ionized water to pan again, after having filtered, filter paper changes in the original molten sample beaker together with precipitation, adds the 40mL chloroazotic acid, continues to be placed on the low temp. electric hot plate and heats, little boiling is dissolved to liquor capacity approximately during 5 ~ 10mL, take off cooling, constant volume 100mL volumetric flask, sand core funnel are done and are filtered.Filtrate is calculated golden mass concentration as detecting liquid with its absorbance of Air-acetylene Flame atomic absorption spectrometry according to the standard working curve method.

Table 1 is to use industry standard YS/T521.3-2006 and method of the present invention to detect result's contrast of gold in the composition brass, as can be seen from Table 1, uses the result of method mensuration gold of the present invention basically identical with the result of industry standard, within the permissible error scope.

Table 1 industry standard and the contrast of the inventive method measurement result

Figure 201210509682X100002DEST_PATH_IMAGE002

Table 2 is the precipitations after separating with volume ratio 50% salpeter solution, and with aqua regia dissolution, to its plasma emission spectrum qualitative analysis, residual each element detects data.Can be found out by table 2 data, matrix copper and other metal, as: iron etc. are most of the separation all, and separating effect is desirable.

Precipitation qualitative test result after table 2 separates

Element

Sn

Fe

Cu

As

Sb

Ni

Pb

Bi

Content/(g/L)

~10

0.1~1

~20

1~10

Table 3 is Precision test result of same sample replicate determination 10 times.Can be found out by table 3 data, this method measurement result is stable, and relative standard deviation is 0.50%.Comprehensive above data can be found out, method of the present invention, and separating effect is desirable, and analysis result is accurate, and favorable reproducibility is simple to operate quick, and saves cost than traditional fiery ensaying, saves the equipment such as high temperature furnace, cupel(lation) furnace, avoids lead contamination, more environmental protection.

Table 3 Precision test result

Figure 201210509682X100002DEST_PATH_IMAGE004

Claims

1. the analytical approach of trace gold in the composition brass is characterized in that bits shape composition brass sample is ground into powder, and takes by weighing 1 ~ 10 and restrains in the 200mL beaker, slowly adds volume ratio 50% salpeter solution 50 ~ 100mL; Behind the question response, heating is boiled, and little boil-off 10min that terminates an agreement takes off cooling; With quantitative Filter paper filtering at a slow speed, use the washed with de-ionized water beaker, the washing lotion total transfer is to pan, precipitate three times with washed with de-ionized water again, filter paper changes in the 200mL beaker of original dissolution sample together with filter residue, add 20 ~ 40mL chloroazotic acid, heating, little boiling is dissolved to liquor capacity approximately during 5 ~ 10mL, take off cooling, constant volume 25 ~ 1000mL volumetric flask, sand core funnel are done and are filtered, with the absorbance of Air-acetylene Flame atomic absorption spectrometry filtrate, calculate the mass concentration of gold according to the standard working curve method.