WO2007029128A1 - Fire assay flux composition for the analysis of pgm and gold containing mineral samples - Google Patents
Fire assay flux composition for the analysis of pgm and gold containing mineral samples Download PDFInfo
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- WO2007029128A1 WO2007029128A1 PCT/IB2006/052844 IB2006052844W WO2007029128A1 WO 2007029128 A1 WO2007029128 A1 WO 2007029128A1 IB 2006052844 W IB2006052844 W IB 2006052844W WO 2007029128 A1 WO2007029128 A1 WO 2007029128A1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B11/00—Obtaining noble metals
- C22B11/02—Obtaining noble metals by dry processes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/20—Metals
Definitions
- This invention relates to a novel flux composition for use in a fire assay, and particularly for use in fire assay analysis of Platinum Group Metals and gold in low and medium-grade samples such as ores and flotation concentrate including furnace mattes and slags.
- fire assay is a method of analysing the quantity of precious metals in ores and metallurgical products.
- Fire assay analysis is commonly employed to collect Platinum Group Metals (hereafter "PGM”) and gold for analysis purposes in low-grade samples, such as ores, where the PGM concentration is too low to measure directly.
- PGM Platinum Group Metals
- PGM and gold fire assay typically involves fusing a finely ground ore sample with a suitable flux, which is generally a lead oxide (litharge) based flux, in the presence of a reductant and at high temperatures ( ⁇ 1200 0 C).
- a suitable flux which is generally a lead oxide (litharge) based flux
- a reductant ⁇ 1200 0 C
- a reaction occurs that liberates the PGM and separation of the precious metals from the gangue is facilitated. More particularly, the litharge in the flux is reduced to minute globules of lead that fall through the melting mass, collecting particles of precious metals, and coalescing as a lead alloy button at the bottom of a crucible. Barren material from the sample, such as chromite and silicate, are dissolved with other components in the flux to form a molten slag.
- chromite and silicate are dissolved with other components in the flux to form a molten slag.
- the lead button On cooling the slag and lead solidify and the lead button containing the precious metals is mechanically separated. The lead button is then analysed for its PGM or gold content through any one of a variety of methods.
- lead In traditional fire assays, lead is removed from the lead alloy button through oxidizing fusion (also known as cupellation) to isolate the precious metals from the lead alloy, after which the precious metals so isolated are analysed.
- oxidizing fusion also known as cupellation
- automated fire assays which are now being introduced, involve direct analytical measurements of the PGM in the lead alloy button through processes such as spark optical emission spectrometry. It is accordingly of utmost importance that the lead alloy button is free from any unwanted impurities that could interfere with the PGM measurements.
- the main constituents of fluxes for fire assay are sodium carbonate (Na 2 CO 3 ), sodium tetraborate (Na 2 B 4 O 7 ), silica (SiO 2 ) and litharge (PbO), together with some or other reductant. More particularly, traditional fluxes for PGM analysis comprise approximately 40% sodium carbonate, 15% sodium tetraborate, 10% silica and 22-28% litharge. The litharge is reduced by the reductant to form metallic lead, which serves as the PGM carrier, while the sodium carbonate, sodium tetraborate and silica are slag formers.
- the sodium carbonate, sodium tetraborate and silica form an oxide slag that dissolves silicates and chromites from the ore sample.
- sodium carbonate has proven to be problematic because of its slow kinetics, resulting in long fusion times.
- the decomposition of sodium carbonate produces carbon dioxide that is released upon reaction with the sample.
- the carbon dioxide gas causes spitting of the charge, which results in physical losses of the sample and slag. This is detrimental to the furnace, as the slag is corrosive. Also, the physical losses may impair the accuracy of the assay.
- PbO is a toxic powder.
- special extraction equipment is necessary in plant environments where PbO is used and operators are required to wear dust masks to prevent inhalation of the toxic dust.
- PbO comprises of fine particles that have poor flow character and tends to choke pipes and equipment in the plant. It is therefore usually necessary to add a binder to the flux composition to granulate the flux for improved handling purposes.
- Carbon reductant In fire assay analysis the reductant is typically carbon based and is commonly added in the form of finely powdered wood charcoal, maize meal or flour, and particularly constitutes between 1% - 2% of the flux composition. Carbon is a strong reductant that reduces litharge to metallic lead, with the evolution of carbon monoxide and/or carbon dioxide.
- iron nail assay A primary disadvantage of iron nail assay is that the process is generally not based on accurate mass-balanced chemical reactions, which results in a host of potential problems.
- Classical iron nail assay tends to use an excess of iron, commonly in the form of large six-inch iron nails, which are removed prior to casting. In some applications an excess of iron filings or several small one-inch nails are also used.
- iron filings or iron nails generally do not react completely, it leaves iron impurities in the lead, which cause spectrograph ⁇ problems in spark analysis. This problem is exacerbated when high chromite content ore samples are fused and accordingly iron nail assay is generally not applied to the analysis of high chromite samples.
- Iron nail analysis has proved satisfactory with some sulphides, but it is, however, not suitable for samples of high sulphide concentration. With such samples, it often happens that there is not enough iron in the reaction, which causes unacceptable levels of sulphur nevertheless to collect in the lead alloy button. Iron nail assay works reasonably well in traditional, non-automated fire assay, where there is enough time for reactions to occur, but the automation of fire assay analysis, where fusion time is shortened, has precipitated the need to have increasingly controlled pyrochemical conditions.
- Chromite samples It will be appreciated that particular challenges are encountered when it comes to analysing ore samples, which are high in chromite content, for their PGM content. Chromite is very refractory and does not fuse easily. Moreover, undissolved chromite retains lead in the slag and the physical loss will result in inaccurate analysis and low analytical bias.
- the applicant refers to the size of a particle by means of a mesh size.
- mesh herein refers to the classification of a collection of particles according to a range of sizes of such particles, and is derived from the sizes of the opening in standard or test sieves used for classifying such particles. For present purposes the United States standard, namely the Tyler designation, was used and all test screens were metric and the nearest equivalent mesh size was taken.
- Classification is to be understood as the process in which two or more sieves are used to separate specific cuts of particles that have sizes falling in a particular size range, from a body of particles having a larger size range.
- a fire assay flux composition for fire assay analysis of PGM and gold, the flux composition comprising a dispersant in the form of a source of phosphate.
- the composition may include between 0.1 % and 12% (m/m of total composition) phosphate, and preferably may include 1.0% (m/m of total composition) phosphate.
- the source of phosphate may be monopotassium phosphate, although the applicant anticipates that the source of phosphate may be selected from the group consisting of potassium phosphates, sodium phosphates, lithium phosphates, their poly phosphates and their hydrates.
- the potassium phosphates may be in the form of di-potassium and tri-potassium phosphates and indeed any potassium poly-phosphate such as potassium pyrophosphate.
- the invention particularly provides a fire assay flux composition for automated fire assay analysis of PGM and gold in low-grade samples with high chromite content, wherein the flux composition comprises a source of phosphate.
- the flux composition also may include iron powder with a particle size of 60 mesh or finer, and preferably with a particle size of 100 mesh, as a primary reductant.
- the flux composition may include between 0.5% (m/m of total composition) and 5% (m/m of total composition) iron powder, and preferably may include 2.2% (m/m of total composition) iron powder.
- the iron powder may be used in the presence of a basic fire assay slag.
- the iron powder is preferably of a high purity, typically being 99% pure and having less than 10ppb (ng.g "1 ) of impurities such as platinum, palladium, gold, rhodium, ruthenium and indium.
- the flux composition may include a secondary reductant selected from the group comprising carbon, magnesium, calcium, silicon and aluminum.
- the secondary reductant is carbon and more particularly powdered steam activated carbon having a particle size of 70 mesh or finer.
- the flux composition may include between 0.01% (m/m of total composition) and 1.0% (m/m of total composition) powdered steam activated carbon, and preferably may include 0.3% (m/m of total composition) powdered steam activated carbon.
- the flux composition may also include at least one basic flux as well as at least one acidic flux.
- the at least one basic flux may be selected from the group consisting of sodium carbonate, sodium hydroxide, potassium carbonate, potassium hydroxide, lime (calcium oxide), calcium carbonate, calcium hydroxide, bismuth oxide (Bi 2 O 3 ) and lead oxide (PbO).
- the at least one acidic flux may be selected from the group consisting of boric acid, sodium tetraborate, sodium metaborate, sodium and potassium phosphates, sodium and potassium sulphates, alumina, silica, calcium silicates and sodium metasilicate calcium/sodium silicate glasses.
- sodium carbonate and PbO may be included as the basic fluxes and all of boric acid, sodium tetraborate, silica and sodium metasilicate may also be included as the acidic fluxes.
- the flux composition may include boric acid as a partial substitute for traditionally used sodium tetraborate. More specifically, the composition may include between 0.1% (m/m of total composition) and 12% (m/m of total composition) boric acid, and preferably may include 0.9% boric acid. The flux composition may include between 5% (m/m of the total composition) and 20% (m/m of the total composition), and preferably may include only 13.4% (m/m of total composition) sodium tetraborate.
- the flux composition also may include sodium metasilicate as a substitute for traditionally used silica and sodium carbonate. More particularly, the composition may include between 5% (m/m of total composition) and 40% (m/m of total composition) sodium metasilicate, and preferably may include 16.8% (m/m of total composition) sodium metasilicate.
- the flux composition may be characterized therein that it includes an excess quantity of PbO of between 15% (m/m of total composition) and 80% (m/m of total composition) PbO, and particularly may include 27% (m/m of total composition) PbO.
- the flux composition also may additionally include between 5% (m/m of total composition) and 40% (m/m of total composition) and preferable approximately 18.5% (m/m of total composition) sodium carbonate.
- the primary and secondary reductants, together with the at least one basic oxide flux and the at least one acid oxide flux may be granulated to form a plurality of granules. At least 80% of the granules so formed have a particle size of between 12 mesh and 32 mesh.
- the dispersant in the form of a source of phosphate with the primary and secondary reductants as well as the at least one basic flux and the at least one acidic flux.
- the fire assay flux composition may be provided in the form of granules.
- the fire assay flux composition may comprise a granular portion and the components, which components are blended together with the granules. It will be appreciated that in alternate embodiments of the invention, the flux composition may be in powder form.
- the fire assay flux composition also may include one or more hydrates characterized therein that they have very low melting points, typically below 100 0 C, so as to dehydrate rapidly to form a barrier to gas movement in the charge, which hydrates may be selected from a group including, although not limited to, hydrated compounds of the various sodium, potassium and lithium silicates and/or borates; hydrated phosphate compounds, such as di-potassium hydrogen orthophosphate tri-hydrate (K 2 HPO 4 .3H 2 O); hydrated carbonates, such as sodium carbonate deca-hydrate (Na 2 CO 3 -IOH 2 O); and their derivatives.
- hydrates may be selected from a group including, although not limited to, hydrated compounds of the various sodium, potassium and lithium silicates and/or borates; hydrated phosphate compounds, such as di-potassium hydrogen orthophosphate tri-hydrate (K 2 HPO 4 .3H 2 O); hydrated carbonates, such as sodium carbonate deca-hydrate (Na 2 CO 3 -I
- the hydrates may have a particle size between 32 mesh and 150 mesh, and are preferably blended together with granules as herein before described.
- the fire assay flux composition may include sodium metaborate tetrahydrate and sodium perborate tetrahydrate, added in combination.
- the particle size of the sodium metaborate tetrahydrate and sodium perborate tetrahydrate is between 32 mesh and 60 mesh. More particularly, the composition may include between 0.5% and 20% (m/m of the total composition) sodium metaborate tetrahydrate, and preferably 4.0% (m/m of the total composition); as well as between 0.5% and 5.0% sodium perborate tetrahydrate; and preferably 1.0% (m/m of the total composition).
- the fire assay flux composition may include sodium tetraborate decahydrate and sodium metasilicate pentahydrate, added in combination.
- the particle size of the sodium tetraborate decahydrate is between 48 mesh and 150 mesh, while the particle size for the sodium metasilicate pentahydrate is between 32 mesh and 60 mesh. At least 80% of the particles fall within the above mesh ranges.
- the composition may include between 0.5% and 20% (m/m of the total composition) sodium tetaborate decahydrate, and preferably 9.0% (m/m of the total composition); as well as between 0.5% and
- a fire assay flux composition for use in fire assay analysis of PGM and gold containing samples, the flux composition comprising high purity iron powder with a particle size of 60 mesh or finer, and preferably with a particle size of 100 mesh, as a primary reductant.
- the flux composition may include between 0.5% and 5% (m/m of total composition) iron powder, and preferably may include 2.3% (m/m of total composition) iron powder.
- the iron powder may be used in the presence of a basic fire assay slag.
- a fire assay flux composition for use in fire assay analysis of PGM and gold containing samples, the flux composition comprising between 0.1% (m/m of total composition) and 12% (m/m of total composition) boric acid, and preferably 0.9% (m/m of total composition) boric acid as a partial substitute for sodium tetraborate.
- the flux composition accordingly may include only approximately 13.4% (m/m of total composition) sodium tetraborate.
- the invention extends to the use of any one or more of a phosphate, and preferably monopotassium phosphate; high purity iron powder with a particle size of 60 mesh or finer, and preferably with a particle size of 100 mesh; powdered activated carbon with a particle size of 70 mesh or finer; boric acid; hydrates, as herein before described and/or sodium metasilicate in the preparation of a flux composition for fire assay analysis of PGM and gold containing samples, and particularly for automated fire assay analysis of PGM and gold in low grade samples.
- a phosphate and preferably monopotassium phosphate
- high purity iron powder with a particle size of 60 mesh or finer, and preferably with a particle size of 100 mesh
- powdered activated carbon with a particle size of 70 mesh or finer
- boric acid hydrates, as herein before described and/or sodium metasilicate in the preparation of a flux composition for fire assay analysis of PGM and gold containing samples, and particularly for automated fire assay analysis
- the invention also extends to the use of high purity iron powder with a particle size of 60 mesh or finer, and preferably with a particle size of 100 mesh as a primary reductant in a flux composition for fire assay analysis of PGM and gold of high chromite content samples.
- the invention also includes the use of between 0.1 % (m/m of total composition) and 12% (m/m of total composition) boric acid, and preferably 0.9% (m/m of total composition) boric acid, as a granulator in a flux composition for automated fire assay analysis of PGM and gold containing samples.
- Example 1 The applicant prepared a flux composition for fire assay analysis of PGM and gold according to the following formulation.
- the real test of a flux is the ability to get a known value on a reference sample. Often the preferred choice is SARM 7B, which is a Merensky Reef sample derived from the South African Bushveld Complex and which is a platinum bearing ore. The method to test the flux can affect the results and these parameters ideally need to be similar.
- this flux composition For the testing of this flux composition, the individual components were weighed out and blended together in a drum mixer. The powdered flux composition was then blended with approximately 6% by mass of water and mixed thoroughly to form small granules. The granules were screened through a 2mm screen and dried overnight in steel pans at 140 0 C, after which the dry granules were blended together. Boric acid was included in the flux composition so as to facilitate the granulation.
- a mass of 5Og sample material was weighed out and mixed with 25Og of the flux composition.
- the mixture was charged into a pre-heated fire clay crucible, which was closed with a ceramic lid and loaded into a bottom loading fusion furnace with a set temperature of 1200 0 C. The charge was allowed to fuse for 15 minutes after which the charge was cast and the liquids separated.
- a rapidly chilled lead disc was prepared in this fashion. The lead disc was weighed and its surface milled before it was analysed for its chemical content using spark optical emission spectrometry. From the PGM content of the lead disc and its mass, the content of the original sample was determined. In addition to the PGM content, the unwanted base metal impurities in the lead sample were also determined.
- the results for the reference material are summarised in the table below.
- the classical flux composition contained only carbon as a reductant.
- the classical flux composition 2 was fused in a similar manner to the new flux composition while the classical flux composition 1 was fused with the traditional method using cold crucibles in a large front-loading fire assay furnace at 1200 0 C for 60 minutes.
- the lowered sulphur content of the sample improved the homogeneity of the spark analysis as was depicted by the percentage relative standard deviation (%RSD) agreement between the spark analyses from different parts of the sample.
- the greater homogeneity ensures greater accuracy of the analysis.
- the fineness of the iron reductant was investigated with a controlled experiment to examine the effect of the iron impurity in the collector after a 15-minute fusion as explained above.
- a 100- mesh iron powder was found to be the most efficient reductant for the application as there were no unreacted iron impurities in the lead collector. While the finer iron powder tended to be carried away with the off gas yielding a slightly smaller lead mass, it was nevertheless efficient and the analysis was accurate. The most usable forms of iron appear to be 60 mesh or finer.
- the iron impurity in the lead collector is essential when analysing the lead collector using spark analysis for the PGM as it is a major source of analytical interference which, because of the poor solubility and inhomogeneity of iron in the lead collector, is difficult to correct for. This is the reason why iron nails or iron filings are not used for this application.
- the iron powder is the primary reductant because it is a good reductant for sulphides present in PGM ores: it selectively removes sulphur as iron sulphide (FeS), which dissolves in basic fire assay slags. This helps to remove the sulphur as an impurity in the lead collector phase, and also reduces copper and nickel impurities in the lead. Moreover, the selective removal of these impurities also reduces losses during cupellation because of less scoria formation (due to nickel removal), surface tension and absorption problems (associated with sulphur). However, an excess of iron powder will cause problems resulting from the formation of iron oxide such as heamatite and magnetite in the slag and usually increased iron oxide scoria formation during cupellation. It is therefore essential that a controlled percentage is added to the formulation.
- FeS iron sulphide
- the iron powder is used in the presence of a basic flux that reacts with the acidic portions of the flux composition to form a sodium-oxide slag.
- Sodium carbonate is the traditional choice as a sodium oxide source, but problems can arise from the excessively rapid carbon dioxide evolution at high temperatures. Therefore, the addition is kept as low as possible, and some of the sodium carbonate is substituted with sodium metasilicate to help control gas evolution while retaining slag basicity.
- a measure of sodium carbonate and carbon dioxide evolution is required for efficient mixing, but needs to be controlled to avoid spitting and frothing of the charge during fusion.
- monopotassium phosphate is particularly beneficial in the analysis of chromite samples, as it prevents adhesion of chromite grains in the slag that form agglomerates in the traditional methods. This prevents the losses of the lead collector to the slag, which is essential for accurate analysis.
- Monopotassium phosphate is the preferred choice due to its low meting point, but the applicant anticipates that di-potassium, tri-potassium phosphates, potassium poly-phosphates such as potassium pyrophosphate, their hydrates and their sodium and lithium phosphate variants could also work.
- the applicant has elected to add sodium metasilicate as a partial substitute for traditionally used silica, because it is not as acidic as silica and requires the use of less sodium carbonate.
- Sodium metasilicate facilitates control of the fusion when charging into a preheated crucible for automation, and also accelerates the fusion process.
- Boric acid which is an acidic fire assay flux, has been used because of its low melting point and because it acts as a coagulant in the early part of the fusion, especially when charging into a hot crucible for automation. It also acts as a binding agent and is useful for granulation purposes.
- powdered activated carbon of 70 mesh or finer was added as a secondary reductant to ensure a consistent button size.
- Powdered activated carbon is preferred to more classical reductants such as flour and maize meal, but it should be borne in mind that the carbon could be substituted by one or more of the elements selected from a group including magnesium, calcium, silicon and aluminum.
- hydrates of the various sodium, potassium and lithium silicates as well as any number of the hydrated compounds of the sodium, potassium and lithium borates.
- hydrated phosphate compounds such as di-potassium hydrogen orthophosphate tri-hydrate (K 2 HPO 4 .3H 2 O)
- carbonates such as sodium carbonate deca-hydrate (Na 2 CO 3 -IOH 2 O)
- the key is that the compound should have a very low melting point due to its water of crystallization, which will dehydrate rapidly forming a barrier to gas movement in the charge.
- the two compounds that have been identified to be best suited to this application are the sodium metaborate tetrahydrate and sodium perborate added in combination.
- the sodium perborate tetrahydrate is very similar in behaviour to the sodium metaborate tetrahydrate, but it is a mild oxidant and adds additional selectivity in the base metal impurity removal from the lead during the fusion.
- Sodium metaborate (NaBO 2 ) once it is dehydrated, has very favourable thermodynamic properties, as its heat capacity is low. Therefore, it may promote conduction of heat into the charge. This is illustrated in the graph below:
- Example 1 To facilitate the change in the flux composition, the composition as set out in Example 1 was modified slightly to accommodate the addition of sodium metaborate tetrahydrate and sodium perborate tetrahydrate. Some of the sodium carbonate and sodium tetraborate were substituted with these compounds. However the final slag composition after the fusion was unchanged by this modification.
- the bulk of the flux components were weighed and blended together, wetted with water and thoroughly mixed to form granules.
- the wet granules were forced through a 2mm wedge wire screen and the resulting granules were dried. Thereafter the powdered sodium metaborate and sodium perborate were blended with the granules.
- Addition of the powdered flux was a total of 10% of the flux mass, while additions of up to 20% of the total flux mass are feasible, although conceivably this could be as high as 64% with only the lead and reductant components along with the boric acid being granulated.
- a mass of 25Og of the flux composition as described above was weighed out and blended with 4Og of sample material. This mixture was added to a pre-heated pot and fused for 15 minutes at a set temperature of 1200 0 C. The molten material was cast into an iron mould and cooled. The lead was mechanically separated from the glass slag and the remaining slag was leached off the lead using dilute hydrochloric acid. The lead was washed with water and dried.
- a disc was formed by pressing the lead in a die with a hydraulic press. The disc was subsequently milled and analyzed, using spark optical emission spectrometry. The grade of the ore was calculated from the lead mass, concentration of PGM in the lead and the sample mass.
- the results from the UG2 reference materials SARM 65 and 72 were compared to the consensus values and showed excellent agreement.
- the Merensky sample SARM 7B was also analyzed and showed superb agreement, satisfying the requirements as a universal flux composition for the analysis of both UG2 (chromite) and Merensky (silicate) samples.
- a further example of a flux composition according to the invention is set out below.
- the bulk of the components above were weighed and blended together, wetted with water and thoroughly mixed to form granules. More particularly it is preferable to sandwich the lead oxide, iron powder and activated carbon between the other components for efficient mixing of the more dense components.
- the components were added to a mixer, which is to be sealed after addition in order to prevent loss of any of the components, in the following order: sodium carbonate, sodium tetraborate, lead oxide, activated carbon, iron powder, sodium silicate, potassium phosphate and boric acid.
- the above components were then dry blended until a homogeneous powdered mixture was formed, after which about 8% to 11% water by mass was added to form the desired granules.
- Preferably the water is to be added as a fine mist.
- the granules were then screened through a screen having a mesh size of 2mm and then subsequently dried until the moisture content thereof was reduced to less than 1% of water by mass.
- the drying was effected by convection heating the granules at a temperature of from 100 0 C to 140 0 C, and typically at 105 0 C for a period of 2 hours. It is important that the granules be checked so that at least 80% of the granules so formed have a particle size of between 32 mesh and 12 mesh.
- the granules so formed are then blended with the following components to provide the fire assay flux composition:
- the sodium tetraborate decahydrate and sodium metasilicate pentahydrate were screened through a 0.5mm screen to remove or break up lumps or agglomerates. It is important that at least 80% of the particles of the sodium tetraborate decahydrate have a particle size of between 48 mesh and 150 mesh. It is further important that at least 80% of the particles of the sodium metasilicate pentahydrate have a particle size of between 32 mesh and 60 mesh.
- the sodium tetraborate decahydrate, sodium metasilicate pentahydrate and silica were added on top of the dry granules in a mixer and blended to ensure a uniform distribution so as to provide the fire assay flux composition having a granular portion and the additional components being blended therewith.
- the flux material prepared above was used in an automated fire assay laboratory to test the compatibility of the material with the flux dosing systems and general handling. The trials that were carried out also tested for the accuracy of the system as certified reference materials were analysed.
- the reference materials were SARM 72 (South African Reference Material), a UG2 ore sample from the Bushveld Complex.
- AMIS 5 and 10 African Mineral Standard
- AMIS 7 an ore sample from the Merensky reef of the Bushveld Complex.
- the robotic system comprised a sample fluxing machine, fusion furnace, a molten slag/collector separator with a water cooled mould. Samples were introduced into the system and the analysis was fully automated with sample manipulation being performed with an articulated robot. An automated spark optical emission spectrometer was used at the end of the system to analyse the lead disc from the fusion circuit in the automated laboratory.
- a mass of 300 grams of flux composition was dosed with the fluxing machine.
- the system added 2 doses of sample (30-50 grams) and the sample/flux composition mixture were mixed for 60 seconds.
- the system discharged the flux composition/sample mixture into a preheated alumina silicate crucible.
- the flux composition/sample mixture was fused in an automated bottom loading furnace for 16 minutes with a temperature of 1260 0 C.
- the molten mixture was then cast into an automated separator device which physically separated the molten glass slag and the metallic lead collector.
- the lead was received in a water cooled mould and rapidly quenched.
- the solid lead disc so formed was then transported with a belt to a spark optical emission spectrometer.
- the lead disc was weighed, milled and then analysed using spark optical emission spectrometry.
- the grade of the sample was calculated from the concentration measured in the lead specimen, the sample mass and the mass of the lead disc.
- AMIS 0010 2.144 1.379 0.441 2.050 ⁇ 0.29 1.330 ⁇ 0.15 0.410 ⁇ 0.08
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Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
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DE112006002407T DE112006002407T5 (en) | 2005-09-06 | 2006-08-17 | Fire sample hot melt composition for the analysis of PGM and gold containing mineral samples |
CA002620863A CA2620863A1 (en) | 2005-09-06 | 2006-08-17 | Fire assay flux composition for the analysis of pgm and gold containing mineral samples |
GB0803393A GB2443139A (en) | 2005-09-06 | 2006-08-17 | Fire assay flux composition for the analysis of PGM and gold containing mineral samples |
AU2006288786A AU2006288786B2 (en) | 2005-09-06 | 2006-08-17 | Fire assay flux composition for the analysis of PGM and gold containing mineral samples |
US11/991,452 US20090071291A1 (en) | 2005-09-06 | 2006-08-17 | Fire Assay Flux Composition for the Analysis of Pgm and gold Containing Mineral Samples |
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ZA200507157 | 2005-09-06 | ||
ZA2005/07157 | 2005-09-06 |
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WO2007029128A1 true WO2007029128A1 (en) | 2007-03-15 |
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AU (1) | AU2006288786B2 (en) |
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CN101905950A (en) * | 2010-07-22 | 2010-12-08 | 刘阳生 | Novel chromium slag innocent treatment method |
CN103575731A (en) * | 2013-11-07 | 2014-02-12 | 广州有色金属研究院 | Measuring method of palladium content in palladium carbon |
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JP5362785B2 (en) * | 2011-07-28 | 2013-12-11 | Jx日鉱日石金属株式会社 | Lead button processing apparatus and lead button processing method |
CN108169216A (en) * | 2017-12-29 | 2018-06-15 | 清远先导材料有限公司 | The assay method of platinum family element in metallurgical material |
CN111812045A (en) * | 2020-06-30 | 2020-10-23 | 新兴铸管股份有限公司 | Method for measuring phosphorus content in high-carbon ferrochrome |
CN112147298B (en) * | 2020-09-27 | 2022-10-25 | 长春黄金研究院有限公司 | Automatic operation method for mixing, melting and blowing fire test gold |
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SU592548A1 (en) * | 1976-08-09 | 1978-02-15 | Киевский Филиал Всесоюзного Научно-Исследовательского И Проектноконструкторского Института Ювелирной Промышленности | Flux for soldering noble metals and threir alloys |
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US6686202B2 (en) * | 2001-08-08 | 2004-02-03 | Placer Dome, Inc. | Methods for detecting and extracting gold |
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2006
- 2006-08-17 GB GB0803393A patent/GB2443139A/en not_active Withdrawn
- 2006-08-17 CA CA002620863A patent/CA2620863A1/en not_active Abandoned
- 2006-08-17 AU AU2006288786A patent/AU2006288786B2/en not_active Ceased
- 2006-08-17 DE DE112006002407T patent/DE112006002407T5/en not_active Withdrawn
- 2006-08-17 US US11/991,452 patent/US20090071291A1/en not_active Abandoned
- 2006-08-17 WO PCT/IB2006/052844 patent/WO2007029128A1/en active Application Filing
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2008
- 2008-02-18 ZA ZA200801583A patent/ZA200801583B/en unknown
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SU592548A1 (en) * | 1976-08-09 | 1978-02-15 | Киевский Филиал Всесоюзного Научно-Исследовательского И Проектноконструкторского Института Ювелирной Промышленности | Flux for soldering noble metals and threir alloys |
US5279644A (en) * | 1993-02-18 | 1994-01-18 | Asarco Incorporated | Fire refining precious metals asay method |
WO2002004919A2 (en) * | 2000-07-12 | 2002-01-17 | Innovative Met Products (Pty) Limited | Method and apparatus for the assay of precious metals |
RU2232825C1 (en) * | 2002-10-23 | 2004-07-20 | Швецов Владимир Алексеевич | Precious metal determination method |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101905950A (en) * | 2010-07-22 | 2010-12-08 | 刘阳生 | Novel chromium slag innocent treatment method |
CN103575731A (en) * | 2013-11-07 | 2014-02-12 | 广州有色金属研究院 | Measuring method of palladium content in palladium carbon |
Also Published As
Publication number | Publication date |
---|---|
DE112006002407T5 (en) | 2008-07-17 |
AU2006288786A1 (en) | 2007-03-15 |
GB2443139A (en) | 2008-04-23 |
GB0803393D0 (en) | 2008-04-02 |
AU2006288786B2 (en) | 2010-12-23 |
US20090071291A1 (en) | 2009-03-19 |
CA2620863A1 (en) | 2007-03-15 |
ZA200801583B (en) | 2010-07-28 |
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