AU2007216909B2 - Copper X-ray flux composition - Google Patents

Abstract

Abstract In the x-ray fluorescence analysis of minerals, ores and other materials, chemicals containing lithium and boron are melted together at high temperatures 5 to produce a borate of lithium which is then cooled and reduced in size to a powder or coarse material. Such material is known as x-ray flux and is usually represented or specified in the final commercial product as ratios of lithium tetraborate to lithium metaborate. The x-ray flux is melted with materials to be analyzed and cast into discs which 10 are then analyzed by an x-ray fluorescence spectrograph. In this invention, tantalum or tantalum compounds have been added, mixed and melted with the x-ray flux such as to function as an internal standard for the quantitative analysis of copper in copper containing substances, copper ores or copper concentrates, when such flux is mixed and melted with the copper 15 containing samples to be analyzed.

Description

Specification for Patent Application Title: "Copper X-Ray Flux Composition" Applicant: X-Ray Flux Pty Ltd 88 Guthrie St., Osborne Park, West Australia 6017 Country: Australia Type: Standard Number: Date: 18 September 1007 Title "COPPER X-RAY FLUX COMPOSITION" 5 Specification The following statement is a full description of this invention, including the best method of performing it known to me: 10 Field of the Invention This invention relates to the analysis of materials, and in particular to an x-ray flux composition for the x-ray fluorescence spectroscopy analysis of copper 15 containing substances, copper ores or copper concentrates. Description Throughout the description, unless the context requires otherwise, the word 20 "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not to the exclusion of any other integer or group of integers. 25 Background X-ray flux is produced by fusing at high temperatures (approximately 1100 degrees C.) in platinum or platinum alloy crucibles, chemicals containing lithium and boron. 30 The molten material is then cooled and reduced in size to a powder or coarse material. The resultant material is x-ray flux and is usually represented or specified in the final commercial product as ratios of lithium tetraborate to lithium metaborate. The x-ray flux as above, is then mixed with samples to be analyzed such as 35 copper containing substances, copper ores or copper concentrates and melted in a platinum or platinum alloy mold. Alternatively, the mixture is melted in a platinum or platinum alloy crucible and subsequently poured into a platinum or platinum alloy mold. The mold is cooled and the result is a glass like disc which is then placed into an x-ray fluorescence spectrograph machine for analysis. 40 Previous difficulties Difficulties exist with the calibration of the x-ray fluorescence spectrograph to get accurate concentration of the target analyte copper in the disc with confidence. 45 In practice, external standards containing known amounts of copper are used to calibrate the spectrograph. Such standards have in turn had to be analyzed by 1 classical wet chemistry techniques which involve hazardous chemicals and which are labour intensive. Such chemical analysis is not generally used for routine analysis because of time constraints. As copper has increased in price over recent years, any increase in accuracy for 5 routine analysis of copper and decrease in time for analysis would mean significant economic advantages for copper producers. Inventive Idea 10 The inventor has found that the element tantalum, a specific transition metal element belonging to group 5 of the periodic table of elements has hitherto unsuspected x-ray fluorescence properties such that when fused together with lithium and boron compounds to form x-ray flux, it is useful as an internal 15 standard for the accurate quantitative determination of copper in copper containing substances, copper ores or copper concentrates when such substances, ores or concentrates are fused with the x-ray flux. Thus in accordance with this aspect of the invention there is presented a copper x-ray fluorescence flux composition for the accurate quantitative determination of 20 copper in copper containing substances, copper ores or copper concentrates, having an ionic moiety of tantalum. It has been found that tantalum has an x-ray fluorescence wavelength close to copper, such that the matrix or interference effect is effectively the same as for copper. 25 Further, the tantalum spectral lines are similarly affected by the other elements usually present in samples of copper containing substances, copper ores or copper concentrates. Consequently, by examining the ratios of the intensity of the wavelength of tantalum to copper, the amount of copper in the fused disc and subsequently in the sample, can be easily and accurately determined 30 mathematically. In addition, the copper x-ray flux composition provides a failsafe analytical technique, in that should the spectral lines for tantalum not be present, the analysis can be considered to have failed, also if the tantalum spectral lines are not present at the known intensity then the x-ray spectrograph could be 35 considered to have been subject to electronic instability and/or drift and therefore not able to give accurate results until realigned or repaired. Best Mode(s) for Carrying Out the Invention 40 The embodiment involves the addition of tantalum or tantalum containing compounds to the lithium and boron containing chemicals before fusing to make the copper x-ray flux composition. The addition of tantalum or tantalum compounds is added such that the 45 percentage of tantalum in the finished copper x-ray flux composition is 0.01 to 60% by weight. 2 Sodium nitrate, lithium nitrate, or other oxidizing compounds, can also be also added to the lithium, boron and tantalum containing compounds after fusing to give a percentage of sodium nitrate, lithium nitrate, or other oxidizing compounds, 5 in the finished copper x-ray flux composition of 1 to 25% by weight. Sodium nitrate, lithium nitrate, or other oxidizing compounds are added if required, to oxidize sulphides when they are present in the copper containing substances, copper ores or copper concentrates, so that such sulphides can be analysed. Release agents such as chemical bromides or iodides can also be added in 10 varying amounts to the flux before or during fusion to aid in the release of the molten material when pouring into molds. A batch of copper x-ray flux is made up by adding to 99.0 grams of lithium tetraborate and lithium metaborate in the proportion of 1.2 parts to 2.2 parts 15 respectively or to a mixture of chemicals which when fused gives the equivalent of fusing the directly aforementioned mixture, 1.0 grams of tantalum oxide (Ta 2 0 3 ). Alternatively a batch of copper x-ray flux composition is made up by adding to 98 or 95 grams of lithium tetraborate and lithium metaborate in the proportion of 1.2 parts to 2.2 parts respectively or to a mixture of chemicals which 20 when fused gives the equivalent of fusing the directly aforesaid mixture, 2.0 or 5.0 grams of tantalum oxide (Ta 2 03) respectively. These ingredients are combined and mixed, and placed in a platinum or platinum alloy crucible and are fused at 1100 degrees C. The fused mix, which forms a liquid glass, is allowed to cool and reduced in size to a coarse material or a powder to produce the finished 25 copper x-ray flux composition. In use, a known quantity of copper containing substances, copper ores or copper concentrates is combined with a known quantity of the finished copper x-ray flux composition, such that the amount of copper containing substances, copper ores 30 or copper concentrates relative to the amount of elemental tantalum present in the copper x-ray flux composition is known. This mixture is melted at high temperature. Typically from 1:1 to 1:30 by weight ratio copper containing substances, copper ores or copper concentrates to copper x-ray flux is usually satisfactory, depending upon the copper containing substances, copper ores or 35 copper concentrates, type and grade. For typical copper containing substances, copper ores or copper concentrates in Australia, 1 gram of material is added to approximately 8 grams of copper x-ray flux composition containing a percentage of sodium nitrate, and melted in a platinum or platinum alloy mold. Alternatively, the copper containing substances, copper ores or copper concentrates and 40 copper x-ray flux composition plus sodium nitrate is melted in a platinum or platinum alloy crucible and poured into a mold. The mold is cooled, the contents forming a glass-like disc which is then placed into an x-ray fluorescence spectrograph machine for analysis. The amount of copper present is determined by analysis of the spectral lines and comparison with the spectral lines of 45 tantalum. 3

Claims (16)

1. A copper x-ray flux composition comprising lithium values and boron values as a borate of lithium, together with tantalum such that the ionic moiety of tantalum is present in proportion of at least 0.01% by weight of boron values in said composition and such flux being specifically used for 10 the quantitative determination of copper in copper containing substances, copper ores or copper concentrates by x-ray fluorescence spectrography.

2. The copper x-ray flux composition of claim 1 where the ionic moiety of tantalum is present in proportion of at least 0.1% by weight of boron 15 values in the said composition.

3. The copper x-ray flux composition of claim 1 where the ionic moiety of tantalum is present in proportion of at least 1.0% by weight of boron values in the said composition. 20

4. The copper x-ray flux composition of claim 1 where the ionic moiety of tantalum is present in proportion of at least 5.0% by weight of boron values in the said composition. 25

5. The copper x-ray flux composition of claim 1 where the ionic moiety of tantalum is present in proportion of at least 10.0% by weight of boron values in the said composition.

6. The copper x-ray flux composition of claim 1 where the ionic moiety of 30 tantalum is present in proportion of at least 20.0% by weight of boron values in the said composition.

7. The copper x-ray flux composition of claim 1 where the ionic moiety of tantalum is present in proportion of up to 60.0% by weight of boron values 35 in the said composition.

8. The copper x-ray flux composition of claim 1 where the ionic moiety of tantalum is present in proportion of 0.01% to 60.0% by weight of boron values in the said composition. 40

9. The copper x-ray flux composition of claim 1 where the ionic moiety of tantalum is present in proportion of about 7% by weight of boron values in the said composition. 45

10. The copper x-ray flux composition of claim 1 where the borate of lithium may be entirely lithium tetraborate. 4

11. The copper x-ray flux composition of claim 1 where the borate of lithium may be entirely lithium meta-borate. 5

12. The copper x-ray flux composition of claim 1 where the borate of lithium comprises a mixture of lithium tetraborate and lithium meta-borate in a range of proportions from 1:10 to 10:1.

13. The copper x-ray flux composition of claim 1 where the borate of lithium 10 comprises a mixture of lithium tetraborate and lithium meta-borate in the proportion of 1.2:2.2 respectively.

14. The copper x-ray flux composition of claim 1 where the lithium may be provided from any lithium containing compound and the boron may be 15 provided from any boron containing compound.

15. The copper x-ray flux composition of claim 1 where the tantalum may be provided from any tantalum containing compound. 20

16. The copper x-ray flux composition of claim 1 where the finished product comprises coarse or finely divided particles of a fusion of compounds of any one of the claims 1 to 15. 25 5