GB2092618A - recovery of precious metals from association with ceramics - Google Patents
recovery of precious metals from association with ceramics Download PDFInfo
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- GB2092618A GB2092618A GB8202341A GB8202341A GB2092618A GB 2092618 A GB2092618 A GB 2092618A GB 8202341 A GB8202341 A GB 8202341A GB 8202341 A GB8202341 A GB 8202341A GB 2092618 A GB2092618 A GB 2092618A
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- charge
- process according
- collector
- metal
- flux
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- 239000010970 precious metal Substances 0.000 title claims abstract description 33
- 238000011084 recovery Methods 0.000 title claims abstract description 15
- 239000000919 ceramic Substances 0.000 title claims abstract description 7
- 229910052751 metal Inorganic materials 0.000 claims abstract description 31
- 239000002184 metal Substances 0.000 claims abstract description 31
- 239000002893 slag Substances 0.000 claims abstract description 24
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 20
- 230000004907 flux Effects 0.000 claims abstract description 18
- 229910052709 silver Inorganic materials 0.000 claims abstract description 13
- 229910010293 ceramic material Inorganic materials 0.000 claims abstract description 11
- 239000000203 mixture Substances 0.000 claims abstract description 10
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 10
- 239000011214 refractory ceramic Substances 0.000 claims abstract description 9
- 239000004332 silver Substances 0.000 claims abstract description 9
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims abstract description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910052802 copper Inorganic materials 0.000 claims abstract description 5
- 239000010949 copper Substances 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 24
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 13
- 229910052757 nitrogen Inorganic materials 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 8
- 239000003570 air Substances 0.000 claims description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 4
- 239000008188 pellet Substances 0.000 claims description 3
- 229910052786 argon Inorganic materials 0.000 claims description 2
- 239000011230 binding agent Substances 0.000 claims description 2
- 239000001307 helium Substances 0.000 claims description 2
- 229910052734 helium Inorganic materials 0.000 claims description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 2
- 238000010923 batch production Methods 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 claims 1
- 239000011819 refractory material Substances 0.000 claims 1
- 229910052681 coesite Inorganic materials 0.000 abstract description 7
- 229910052906 cristobalite Inorganic materials 0.000 abstract description 7
- 235000012239 silicon dioxide Nutrition 0.000 abstract description 7
- 229910052682 stishovite Inorganic materials 0.000 abstract description 7
- 229910052905 tridymite Inorganic materials 0.000 abstract description 7
- 150000002739 metals Chemical class 0.000 abstract description 3
- 229910002113 barium titanate Inorganic materials 0.000 description 26
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 description 14
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 12
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 10
- 239000000758 substrate Substances 0.000 description 8
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 7
- 238000003556 assay Methods 0.000 description 7
- 238000002844 melting Methods 0.000 description 7
- 230000008018 melting Effects 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 239000010439 graphite Substances 0.000 description 6
- 229910002804 graphite Inorganic materials 0.000 description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 229910052763 palladium Inorganic materials 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- 229910052697 platinum Inorganic materials 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 229910000519 Ferrosilicon Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 229910052797 bismuth Inorganic materials 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000010891 electric arc Methods 0.000 description 2
- 239000010792 electronic scrap Substances 0.000 description 2
- 238000011067 equilibration Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- -1 platinum group metals Chemical class 0.000 description 2
- 238000010408 sweeping Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 241000511343 Chondrostoma nasus Species 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 229910018619 Si-Fe Inorganic materials 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 229910008289 Si—Fe Inorganic materials 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 1
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 1
- 238000004581 coalescence Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000012776 electronic material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 230000009931 harmful effect Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910003465 moissanite Inorganic materials 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- SWELZOZIOHGSPA-UHFFFAOYSA-N palladium silver Chemical compound [Pd].[Ag] SWELZOZIOHGSPA-UHFFFAOYSA-N 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Classifications
-
- 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
- C22B11/021—Recovery of noble metals from waste materials
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention relates to the recovery of precious metal deposited upon or contained in refractory ceramic materials by preparing in divided form a charge containing the said refractory ceramic materials bearing precious metal, optionally a flux and optionally a metallic collector such that at least 2% by weight of precious metal plus collector metal (if included) is present. The charge is subjected to a temperature of at least 1400 DEG C to produce a molten metallic phase containing a substantial proportion of the said precious metal=and collector metal (if included) and a slag phase containing ceramic residues and the remainder of the metal and separating the two phases. The flux may be SiO2 or a mixture of SiO2 and Fe2O3 in the weight ratio of 1:1.5. Preferred collector metals are copper or silver.
Description
SPECIFICATION
Recovery of precious metals
This invention relates to the recovery of precious metals which may be present in or associated with ceramic materials, that is to say the secondary refining or recovery of such metals rather than the primary refining of the ore containing them.
At the present time large quantities of ceramic materials, particularly refactory ceramic materials such as barium titanate, titanium dioxide, alumina, zirconia, ceria, calcium oxide and silica are scrapped by the electronics and related industries and their users. Such scrap frequently contains significant quantities of precious metals such as platinum, iridium, palladium silver and gold. Smaller quantities of ruthenium and rhodium may also be present. However, the high melting point of refractory based ceramic substrates such as barium titanate presents a slag problem when attempts are made to recover the precious metal using conventional pyrometallurgical techniques.
Blast and reverberatory furnaces normally operate at temperatures in the range 1250-1 3500C which is considerably below 1 61 20C, the melting point of barium titanate. At these higher temperatures conventional prior art techniques would require inclusion in the charge of a substantial proportion of slag material such as Woliastonite or Olivine in order to dissolve the refractory. However, this renders the process economically less viable because of the increased loss of precious metal in the slag. One object of the present invention is to recover a larger proportion of the said precious metal than that obtainable by use of prior art processes.
According to the present invention a process for the recovery of precious metal deposited upon or contained in refractory ceramic materials, for example, substrates comprises preparing in divided form a charge containing the said refractory ceramic substrate bearing precious metal, optionally a flux and optionally a metallic collector, such that at least 2% by weight of precious metal plus collector metal (if included) is present, subjecting the charge to a temperature of at least 1 4000C to produce a molten metallic phase containing a substantial proportion of the said precious metal and collector metal (if included) and a slag phase containing ceramic residues and the remainder of the metal and separating the two phases.
A collector metal need not be present because if not less than 2% by weight of precious metal is included it will act as its own collector. Preferably, a higher proportion of precious metal should be present in the charge. We prefer to use 25% by weight, but considerably more precious metal may be included without any harmful effects. Suitable collector metals if needed are silver or copper in divided form. The presence of a flux is not essential but a SiO2 containing flux is preferred if one is used. If used, the flux is preferably present in the range 710% by weight in the charge and it is useful in lowering the melting point and the viscosity of the slag phase. An alternative flux which can be used is a mixture of SiO2 and Fe203 in the weight ratio 1:1.5.
In order to produce a fluid slag with a low viscosity and hence optimise recovery, the operating temperature needs to be about 1000C above the melting point of the substrate and we, therefore, prefer operating temperatures in the range 1500--17500C, although an operating temperature as low as 14000C can be used with the above-mentioned SiO2 and Fe203 flux. Such temperatures can be achieved using high heat intensity furnaces, for example, submerged electric arc furnaces and plasmaarc furnaces, which latter furnaces are known for primary refining but not for secondary refining.
Because submerged electric arc furnaces produce undesirable agitation of the charge, plasma arc furnaces are to be preferred and we have tested a variety of different types inter alia furnaces incorporating expanded plasma systems, furnaces having a static gun, and extended arc furnaces including a transferred plasma arc furnace. Only furnaces adapted for batch operation have been tried but a continuous operation furnace with provision for continuous removal of the slag and/or metallic phases could be used. The process of this invention is operable with all types of high heat intensity furnaces tested though with varying degrees of success. It is considered, however, that the differences in recovery obtained were related primarily to the charge formulation and only to a limited extent upon the type of plasma furnace used.
Suitable gases for the plasma are air, argon, helium or nitrogen.
The divided charge is fed gradually into the furnace through the plasma arc, and inbatch processes, it is desirable to continue the discharge of the plasma arc for a minimum holding period after passing the entire charge therethrough, the minimum holding period preferably being from 5 to 30 mins.
The charge is prepared by mixing in suitabie proportions the precious metal bearing substrate material reduced to a finely divided form by crushing with the flux and collector metal, if included. If desired the substrate may be reduced by (e.g.) crushing and mixed with the selected flux and collector metal (if included), the mixture then being compacted to produce pellets. A binder material preferably in an amount of 2% by wt of the mixture, can be used to ensure adequate green strength.
The grain size of the charge is selected inter alia to ensure intimate contact between the charge and the plasma and to avoid undue losses by entrainment in the gas flow through the plasma furnace.
It is preferred to reduce the charge to the range minus 10-minus 200 mesh but in trials we have conducted, the best results have been obtained at minus 8 mesh (2.8 mm).
Satisfactory results, have however, been obtained using ceramic chips measuring 3 mm x 6 mm and pellets compacted from a finely divided mixture of the refractory substrate, flux and collector, having a diameter of TIt.
As for the collector material, if sufficient precious metal is present in the charge i.e. at least 2%, preferably about 57% by weight, a collector metal is not necessary. If insufficient precious metal is present in the charge, copper or silver preferably in divided form may be added to the charge to bring the metallic content up to about 57% by weight.
Silver may be added in crystalline or finely divided form or it may be added as a sweep such as photographic film ash. Because silver is regarded as a precious metal the present invention has the advantage of producing a bullion with no base metal collector present. However, in the case of some electronic scrap material a bullion will be produced containing both silver and platinum group metals, particularly palladium. Since it is preferred to keep silver and palladium separate, a subsequent step of melting the bullion with ferrosilicon (which is 20% Si-Fe) gives 2 immiscible phases with 97% by weight of the platinum group metal associated with the ferrosilicon phase and 97% of the silver as a separate phase.
Separation of the slag and metallic phases and separation of the precious metals from the metallic phase, after cooling thereof, may be effected by the known methods.
EXAMPLE 1: Barium Titanate with nitrogen plasma
20.4 kg of a charge of barium titanate bearing precious metal had a head assay as follows: %wiw Pt 2.25
Ir 0.2
Pd 4.05
Au 0.05
Ag 9.45 was treated in a plasma arc furnace using a graphite crucible. After passage of the charge 5 minutes was allowed to enable equilibrium to be obtained before switching off.
Using an atmosphere of nitrogen and 270 kilowatt supply to the plasma arc of the furnace, 12.29 kg of slag were recovered having an assay: % w/w Pt 0.4
Pd 0.55
Ag 1.24 giving a recovery on the head assay of 89.1% Pt, 91.7% Pd and 92.1% Ag by weight.
EXAMPLE 2: Barium titanate with an air plasma
A charge of 20.0 kg having the same head assay as in Example 1 was fed through a plasma arc at 220 kilowatts using an atmosphere of air. A holding time of 1 5 minutes was allowed after feeding in the charge and 13.77 kg of slag was recovered having an assay: %w/w Pt 0.125
Pd 0.24
Ag 0.15 giving a recovery on the head assay of 96.2% Pt, 96% Pd and 99% Ag by weight.
EXAMPLE 3: Barium Titanate with a nitrogen plasma
Charge: 20 kg barium titanate -- BaTiO, (quoted assay Pd 2.37%, Ag 2.61%)
Plasma gas: nitrogen at 6 cfm-'; Plasma gun - water cooled with copper electrode
Feed rate: 5 kg at 2 kg/minute, balance at 1.15 kg/minute
The concentration of precious metals in the barium titanate was sufficient to act as a self-collector system. Since barium titanate has a M.P. of 161 20C an operating temperature of about 1 7000C was
employed although somewhat lower temperatures could also be used.
After preheating a new graphite crucible (200-21 9 kW) for 12 minutes, 5 kg of BaTiO3 chips were added at 2 kg/minute (198--219 kW). 5 minutes later the charge was inspected and appeared to be fluid. The balance of the charge was then added at 1.15 kg/minute and the power reduced to 1 87 kW. When all the BaTiO3 had been added to the furnace, the products were allowed to equilibrate for a further 12 minutes and the power was further reduced to 136 kW.
Although melting was incomplete (probably due to the decrease in the power input subsequent to the initial 5 kg of charge), several large metallic agglomerates were formed and removed from the slag.
EXAMPLE 4: Remelt of product from Example 3 with an air plasma
Charge: 1 5.5 kg BaTiO3 slag from examples.
Plasma gas: air at 6.5-7.0 cfm-1; Plasma gun as in Example 3
No nitrogen was used for this experiment and the plasma gas was air. The crucible was preheated for 25 minutes with the plasma at 220 kW. The partially melted BaTiO3 product from Example 3 was broken up and added to a graphite crucible in five separate batches at 3-7 minute intervals. When all the BaTiO3 was added the melt was allowed to equilibrate for a further 1 5 minutes at 220 kW.
Separation of the products from the graphite crucible was very easy. Although the charge had been completely molten, the coalescence of the metal phase was still incomplete and several small prills were still visible in the lower section of the slag. The distribution and shape of the metal p'nase suggested that the slag was too viscous.
Wt. of metal recovered - 1.02 kg
Wt. of slag + small prills -- 14.36 kg
Combined results of Examples 3 and 4:
Input - 20 kg BaTiO3 chips
Output - Metal recovered - 2.62 kg
Slag + small prills - 14.36keg Estimated wt. of furnace sweepings - 2.00 kg
Total 18.98 kg
The total weight of metal recovered, excluding the small prills in the slag, represented 15.2% of the charge which represents a considerably higher than anticipated metal recovery.The total estimated loss of volatile constituents during the trial was about 1.0 kg, i.e. 5%. A sample of condensate from the water cooled gun was qualitatively analysed by XRF and showed that the major constituents were Pb,
Ag and Bi with minor amounts of Br, I and Zn. The slag from Example 4 was crushed, ground and further refined before assaying.
EXAMPLE 5: Barium titanate with a nitrogen plasma
Charge: 20.4 kg BaTiO3 chips
Plasma gas: N2 at 6.75 cfm-l; plasma gun as in Example 3
Feed rate: 0.9 kg-minute
A graphite crucible was preheated for 20 minutes at 250 kW and this power rating was maintained throughout the trial. After approximately 5 kg of BaTiO3 was added the feed was stopped for 3 minutes and the crucible was inspected to ensure the charge was completely molten. The balance of the BaTiO3 was then added at 0.9 kg/minute.
Total wt. of molten products - 1 5.675 kg
Wt. of residue in vibro feeder - 0.755 kg
Wt. of unmelted furnace sweepings - 3.000 kg
19.430 kg
Loss on melting -- 0.97 kg i.e. similar to Examples 3 and 4.
The BaTiO3 had completely melted but due to the short equilibration period the metallics were dispersed as prills throughout the slag and 640 g-of metal was easily recovered.
EXAMPLE 6: Remelt of product from trial 5. with a nitrogen plasma
Charge: 15.035 kg of BaTiO3 from Example 5
Plasma gas: N2 at 5.75-6.5 cfm-1; Plasma gun as for Example 3
After preheating the graphite crucible at 270 kW for 20 minutes the power was reduced to 264 kW. The product from Example 5 was broken up and added to the crucible in five batches as described in Example 4. 5 minutes after the last batch of BaTiO3 was added an inspection showed that the charge was completely molten.
Wt. of slag + small prills -- 12.07 kg
Wt. of metal recovered - 1.53 kg
Total metal recovered from Examples 5 and 6 - 12.14 Kg i.e. 13.6% of charge.
EXAMPLE 7
38.13 Kg barium titanate electronic scrap having the following precious metal composition: % w/w Pt 2.19
Pd 3.71
Au 0.06
Ag 9.15 was milled and mixed with SiO2 and Fe2O3 to give the following charge:
Barium titanate scrap 38.13 Kg
SiO2 4.95 Kg Fe203 8.07 Kg
The mixture was tabletted and fed into the plasma furnace at 0.72 kg/min with an input power of 200 Kw. After the charge was completely molten a further 15 minutes equilibration was allowed with the plasma remaining switched on. The weight of slag produced was 43.12 Kg and 7.3 Kg of metal recovered. The weight of metal after remelting to remove entrained slag was 6.746 Kg. The composition of the remelted metal and the respective recoveries of precious metals were as follows: %w/w % Recovery
Pt 9.95 80.3
Pd 19.75 94.2
Au 0.4 apparent metal gain
Ag 39.19 76
These foregoing examples were carried out in a plasma arc furnace supplied by Technology
Application Services Corporation of North Carolina, U.S.A.
Although these examples refer specifically to a charge of barium titanate bearing precious metal, the underlying concept of the present invention may also be applied to other charges, for example, refractory washcoats which, conventionally, may include alumina from metallic and ceramic substrates, silica based materials, and materials, particularly electronic materials containing TiO2, Zero2, Ce203,
La203 (and other rare earth oxides), SiC, Si3N4 and bismuth containing electronic components.
Claims (14)
1. A process for the recovery of precious metal deposited upon or contained in refractory ceramic materials comprising preparing in divided from a charge containing the said refractory ceramic materials bearing precious metal, optionally a flux and optionally a metallic collector, such that at least 2% by weight of precious metal plus collector metal (if included) is present, subjecting the charge to a temperature of at least 1 4000C to produce a molten metallic phase containing a substantial proportion of the said precious metal and collector metal (if included) and a slag phase containing ceramic residues and the remainder of the metal and separating the two phases.
2. A process according to claim 1 wherein a silica containing flux is used.
3. A process according to claim 2 wherein Fe203 is also present in the flux.
4. A process according to claim 1 or claim 2 wherein the charge is heated to a temperature in the range 1 500-1 7500C.
5. A process according to any one of the preceding claims wherein the charge is heated in a high intensity heating furnace.
6. A process according to claim 4 wherein the said furnace is a plasma arc furnace.
7. A process according to claim 5 wherein the gas for plasma arc furnace is selected from the group consisting of argon, helium, nitrogen and air.
8. A process according to claim 2 wherein the flux content of the charge is up to 25% by weight of the refractory ceramic material content of the charge.
9. A process according to claim 7 wherein the flux content of the charge is up to 10% by weight of the refractory ceramic material content of the charge.
10. A process according to any one of the preceding claims wherein the collector material content of the charge is 2 to 10% of the refractory material content of the charge.
11. A process according to any one of the preceding claims wherein the collector materials is selected from the group copper, silver or mixtures thereof.
12. A process according to any one of claims 1 to 11 wherein the refractory ceramic material is reduced to finaly divided form by crushing or the like.
1 3. A process according to claim 12 wherein the finely divided material has a mesh size in the range minus 10 to minus 200 mesh.
14. A process according to claim 12 wherein the material in finely divided form is mixed with the flux or fluxes and collector material, and the charge so produced is compacted to form charge pellets.
1 5. A process according to claim 14 wherein 2% by weight of a binder material is added to the finely divided charge.
1 6. A process according to claim 5 and which is a batch process, wherein the divided charge is fed into the furnace'through the plasma arc and wherein discharge of the plasma arc is continued for a minimum holdingxperiod after passing the entire charge therethrough.
1 7. A process for the recovery of precious metal substantially as hereinbefore described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8202341A GB2092618B (en) | 1981-02-05 | 1982-01-27 | Recovery of precious metals from association with ceramics |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8103570 | 1981-02-05 | ||
| GB8202341A GB2092618B (en) | 1981-02-05 | 1982-01-27 | Recovery of precious metals from association with ceramics |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2092618A true GB2092618A (en) | 1982-08-18 |
| GB2092618B GB2092618B (en) | 1985-06-26 |
Family
ID=26278342
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8202341A Expired GB2092618B (en) | 1981-02-05 | 1982-01-27 | Recovery of precious metals from association with ceramics |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2092618B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0076049A1 (en) * | 1981-09-16 | 1983-04-06 | Matthey Rustenburg Refiners (Proprietary) Limited | Recovery of precious metals from leach residues |
| EP0077128A1 (en) * | 1981-09-16 | 1983-04-20 | Matthey Rustenburg Refiners (Proprietary) Limited | Recovery of platinum group metals from scrap and residues |
| WO1986005211A1 (en) * | 1985-02-27 | 1986-09-12 | Boliden Aktiebolag | A method for working-up waste products containing valuable metals |
| WO1986005243A1 (en) * | 1985-03-05 | 1986-09-12 | Nilsson Nils Enar | A device for synchronized hydraulic fluid supply of two or more hydraulic motors |
| US8101304B2 (en) * | 2003-05-16 | 2012-01-24 | Umicore Ag & Co. Kg | Process for the concentration of noble metals from fluorine-containing fuel cell components |
-
1982
- 1982-01-27 GB GB8202341A patent/GB2092618B/en not_active Expired
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0076049A1 (en) * | 1981-09-16 | 1983-04-06 | Matthey Rustenburg Refiners (Proprietary) Limited | Recovery of precious metals from leach residues |
| EP0077128A1 (en) * | 1981-09-16 | 1983-04-20 | Matthey Rustenburg Refiners (Proprietary) Limited | Recovery of platinum group metals from scrap and residues |
| WO1986005211A1 (en) * | 1985-02-27 | 1986-09-12 | Boliden Aktiebolag | A method for working-up waste products containing valuable metals |
| US4705562A (en) * | 1985-02-27 | 1987-11-10 | Boliden Aktiebolag | Method for working-up waste products containing valuable metals |
| AU571127B2 (en) * | 1985-02-27 | 1988-03-31 | Boliden Aktiebolag | A method for working-up waste products containing valuable metals |
| WO1986005243A1 (en) * | 1985-03-05 | 1986-09-12 | Nilsson Nils Enar | A device for synchronized hydraulic fluid supply of two or more hydraulic motors |
| US8101304B2 (en) * | 2003-05-16 | 2012-01-24 | Umicore Ag & Co. Kg | Process for the concentration of noble metals from fluorine-containing fuel cell components |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2092618B (en) | 1985-06-26 |
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| PCNP | Patent ceased through non-payment of renewal fee |