AU650802B2 - Extraction or recovery of metal values - Google Patents
Extraction or recovery of metal values Download PDFInfo
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- AU650802B2 AU650802B2 AU28647/92A AU2864792A AU650802B2 AU 650802 B2 AU650802 B2 AU 650802B2 AU 28647/92 A AU28647/92 A AU 28647/92A AU 2864792 A AU2864792 A AU 2864792A AU 650802 B2 AU650802 B2 AU 650802B2
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- AU
- Australia
- Prior art keywords
- process according
- arsenic
- iron
- solution
- nitric acid
- Prior art date
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- 229910052751 metal Inorganic materials 0.000 title claims description 23
- 239000002184 metal Substances 0.000 title claims description 23
- 238000011084 recovery Methods 0.000 title claims description 20
- 238000000605 extraction Methods 0.000 title claims description 13
- 229910052785 arsenic Inorganic materials 0.000 claims description 41
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 claims description 41
- 239000000243 solution Substances 0.000 claims description 38
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 32
- 238000000034 method Methods 0.000 claims description 29
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 26
- 229910017604 nitric acid Inorganic materials 0.000 claims description 26
- 238000000926 separation method Methods 0.000 claims description 24
- 239000007787 solid Substances 0.000 claims description 17
- 238000002386 leaching Methods 0.000 claims description 16
- 239000007788 liquid Substances 0.000 claims description 16
- 238000001556 precipitation Methods 0.000 claims description 15
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 13
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims description 12
- BMWMWYBEJWFCJI-UHFFFAOYSA-K iron(3+);trioxido(oxo)-$l^{5}-arsane Chemical compound [Fe+3].[O-][As]([O-])([O-])=O BMWMWYBEJWFCJI-UHFFFAOYSA-K 0.000 claims description 12
- 239000003795 chemical substances by application Substances 0.000 claims description 11
- 239000002244 precipitate Substances 0.000 claims description 11
- 239000001117 sulphuric acid Substances 0.000 claims description 11
- 235000011149 sulphuric acid Nutrition 0.000 claims description 11
- 229910052742 iron Inorganic materials 0.000 claims description 10
- 239000007791 liquid phase Substances 0.000 claims description 10
- 230000003472 neutralizing effect Effects 0.000 claims description 10
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 10
- 229910021653 sulphate ion Inorganic materials 0.000 claims description 10
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 9
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 claims description 8
- LULLIKNODDLMDQ-UHFFFAOYSA-N arsenic(3+) Chemical compound [As+3] LULLIKNODDLMDQ-UHFFFAOYSA-N 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 239000011575 calcium Substances 0.000 claims description 6
- -1 chloride anions Chemical class 0.000 claims description 6
- 150000002739 metals Chemical class 0.000 claims description 6
- 229910002651 NO3 Inorganic materials 0.000 claims description 5
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 5
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 5
- 239000000920 calcium hydroxide Substances 0.000 claims description 5
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 5
- HUEBVZADHUOMHL-UHFFFAOYSA-N [As].[Pb] Chemical compound [As].[Pb] HUEBVZADHUOMHL-UHFFFAOYSA-N 0.000 claims description 4
- 239000003929 acidic solution Substances 0.000 claims description 4
- 230000008929 regeneration Effects 0.000 claims description 4
- 238000011069 regeneration method Methods 0.000 claims description 4
- 239000007790 solid phase Substances 0.000 claims description 4
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 3
- VETKVGYBAMGARK-UHFFFAOYSA-N arsanylidyneiron Chemical compound [As]#[Fe] VETKVGYBAMGARK-UHFFFAOYSA-N 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 239000007800 oxidant agent Substances 0.000 claims description 3
- 230000001590 oxidative effect Effects 0.000 claims description 3
- 150000001875 compounds Chemical class 0.000 claims description 2
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 claims description 2
- 229910052683 pyrite Inorganic materials 0.000 claims description 2
- 239000011028 pyrite Substances 0.000 claims description 2
- JGFZNNIVVJXRND-UHFFFAOYSA-N N,N-Diisopropylethylamine (DIPEA) Chemical compound CCN(C(C)C)C(C)C JGFZNNIVVJXRND-UHFFFAOYSA-N 0.000 claims 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 8
- 229910052725 zinc Inorganic materials 0.000 description 8
- 239000011701 zinc Substances 0.000 description 8
- 238000004090 dissolution Methods 0.000 description 6
- 238000007792 addition Methods 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- 230000002378 acidificating effect Effects 0.000 description 3
- 229910052976 metal sulfide Inorganic materials 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- RMBBSOLAGVEUSI-UHFFFAOYSA-H Calcium arsenate Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-][As]([O-])([O-])=O.[O-][As]([O-])([O-])=O RMBBSOLAGVEUSI-UHFFFAOYSA-H 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 229940103357 calcium arsenate Drugs 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000002203 pretreatment Methods 0.000 description 2
- KEQXNNJHMWSZHK-UHFFFAOYSA-L 1,3,2,4$l^{2}-dioxathiaplumbetane 2,2-dioxide Chemical compound [Pb+2].[O-]S([O-])(=O)=O KEQXNNJHMWSZHK-UHFFFAOYSA-L 0.000 description 1
- DJHGAFSJWGLOIV-UHFFFAOYSA-K Arsenate3- Chemical compound [O-][As]([O-])([O-])=O DJHGAFSJWGLOIV-UHFFFAOYSA-K 0.000 description 1
- 239000005083 Zinc sulfide Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229940000489 arsenate Drugs 0.000 description 1
- HAYXDMNJJFVXCI-UHFFFAOYSA-N arsenic(5+) Chemical compound [As+5] HAYXDMNJJFVXCI-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- NFMAZVUSKIJEIH-UHFFFAOYSA-N bis(sulfanylidene)iron Chemical compound S=[Fe]=S NFMAZVUSKIJEIH-UHFFFAOYSA-N 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 description 1
- 238000005363 electrowinning Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 150000002506 iron compounds Chemical class 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- ZODDGFAZWTZOSI-UHFFFAOYSA-N nitric acid;sulfuric acid Chemical compound O[N+]([O-])=O.OS(O)(=O)=O ZODDGFAZWTZOSI-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000011027 product recovery Methods 0.000 description 1
- 238000009853 pyrometallurgy Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 150000004763 sulfides Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- Manufacture And Refinement Of Metals (AREA)
- Treatment Of Liquids With Adsorbents In General (AREA)
Description
OPI DATE 21/05/93 APPLN. ID 28647/92 ll lil lll ll! AOJP DATE 22/07/93 PCT NUMBER PCT/AU92/00570 Ilillll ll 11111il1 AU9228647 lN Ir'cK IN4 IUINAL Ar'L-AllA 1UN PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 5 (11) International Publication Number: WO 93/08310 C22B 3/06, 3/44 C22B 19:00 Al C22B 15:00, 23:04 11:00 (43) International Publication Date: 29 April 1993 (29.04.93) (21) International Application Number: PCT/AU92/00570 (74) Agent: OBERIN, Colin, Oberins Patent and Trade Mark Attorneys, 66 Croydon Road, Croydon, VIC 3136 (22) International Filing Date: 23 October 1992 (23.10.92) (AU).
Priority data: (81) Designated States: AT, AU, BB, BG, BR, CA, CH, CS, PK9105 25 October 1991 (25.10.91) AU DE, DK, ES, FI, GB, HU, JP, KP, KR, LK, LU, MG, MN, MW, NL, NO, PL, RO, RU, SD, SE, US, European patent (AT, BE, CH, DE, DK, ES, FR, GB, GR, (71)Applicant (for all designated States except US): SASOX IE, IT, LU, MC, NL, SE), OAPi patent (BF, BJ, CF, PROCESSING PTY. LIMITED [AU/AU]; 22 Stirling CG, Cl, CM, GA, GN, ML, MR, SN, TD, TG).
Highway, Nedlands, W.A. 6009 (AU).
(72) Inventors; and Published Inventors/Applicants (for US only) WHELLOCK, John, With international search report.
Graham [GB/US]; 9200 Cherry Creek Drive South, #22, Denver, CO 80231 LEONARD, Rodnay, Lloyd [US/AU]; 112B Empire Avenue, Wembley Downes, W.A. 6019 (AU).
(54) Title: EXTRACTION OR RECOVERY OF METAL VALUES Pb Dross FES,/FE, (S04), w/As -Steam HNO, w/s 1.
NITRIC ACID O NITRIC ACID LEACH SOLID/LIQUID Solids Poc NO, ol'n Pb SO, Product RECOVERY I (85' 90C)
SEPARATION
SOLID/LIQUID SULFURIC ACID SEPARATION
(OPTIONAL)
ARSENIC/IRON
Ca(OH), PRECIPITATION From Zinc Recovery STAGES (80'-85'C) SOLID/LIQUID Ferric Arsenate Iron Residues To SEPARATION Waste Disposal Ca PRECIPITATION
SOLID/LIQUID
SOLID/LQ Cu Metals Product
SEPARATION
To Zinc'Recovery (57) Abstract A process suitable for the extraction or recovery of metal values from arsenic containing feeds and including the steps of: a) treating the feed with a nitric acid-containing leachant solution in order to dissolve the desired metals; b) adding a source of iron (III) to the leachant solution whereby to oxidise arsenic (III) in solution to arsenic c) adding a neutralising agent to the leachant solution whereby to precipitate arsenic as arsenic d) separating the arsenic precipitate from the leachant solution; and e) recovering metal values from the leachant solution, WO 93/08310 PCr/AU92/00570 EXTRACTION OR RECOVERY OF METAL VALUES BACKGROUND OF THE INVENTION The present invention relates to the extraction or recovery of metal values from feed materials and more particularly to the extraction or recovery of metal values from feeds not amenable to efficient extraction by conventional ;.Lethods.
It is well known that many non-ferrous metal sulphide materials may be dissolved in nitric acid or other acidic solutions containing an oxidizing agent comprising dissolved oxides of nitrogen. A nitric acid-sulphuric acid mixture is one such acidic solution. Examples of such prior art include European Patent Application 87310905.2 (Electrolytic Zinc Company of Australasia Limited). This is typical of the known prior art in that it relates to the oxidative leaching of metal sulphides such as zinc sulphide concentrates.
The known prior art is typically concerned with the treatment of copper- and zinc-containing sulphides. These feeds can be classed as non-refractory being relatively simple feeds to process. However, many feeds particularly those that are the intermediate products of other processes including hydrometallurgical and pyrometallurgical processes are generally considered difficult to treat. With such difficult-to-treat feeds the dissolution of the valuable components may be inhibited, for example, by passivation.
Accordingly they are not amenable to extraction or recovery by conventional methods such as direct treatment with aqueous solutions containing nitric acid or sulphuric acid.
Therefore, it has hitherto been considered that in order to achieve acceptable dissolution rates with such feeds, some form of pre-treatment such as roasting is required. Such pre-treatment is cbstly in terms of both capital costs and operating costs, may cause the dissolution of undesirable components of the feed and may not yield complete dissolution of the desired metals. Alternatively, processing conditions may need to be extremely aggressive to achieve commercially viable rates of reaction.
WO 93/08310 PCr/AU92/0070 2 Processing difficulties are compounded when the feed contains arsenic. Safe disposal of arsenic-containing residues is an important consideration. Many countries have strict mandatory limits on the allowable arsenic levels of wastes from processing operations which are intended to be held in tailings dams or otherwise disposed of.
One conventional method of processing arsenic-containing feeds is by ferric sulphate leaching. During processing of arsenic-containing feeds by ferric sulphate leaching, only a portion of the arsenic (III) is generally oxidized to arsenic The arsenic (III) remains soluble in the aqueous processing media while the arsenic is precipitated as a hydrated ferric arsenate (ideally Fe AsO 4 .xH 2 It is known to use an excess of soluble iron in the arsenic precipitation circuit to inhibit the redissolving of arsenic from the ferric arsenate precipitate which is typically disposed of in tailings dams. Typically the Fe/As molar ratio in the precipitate must be at least 4:1. The soluble arsenic (III) which is present in the leach liquor needs to be removed before the metal values can be recovered or excess process water disposed of in an environmentally acceptable manner.
Such additional process steps involve the use of additional reagents and can lead to significant increases in both capital and operating costs.
Precipitation of an' rnvironmentally stable arseniccontaining product is difficult to achieve with feeds in which the iron content is below that required for the precipitation of an iron arsenate with a Fe/As ratio of 4/1 or above. Previous practice has been to provide sufficient calcium cations to precipitate calcium arsenate for "total" arsenic precipitation. At the same time the pH of the slurry is adjusted to the appropriate range. However, it is known that calcium arsenate is more chemically reactive than ferric arsenate and is not regarded as an acceptable alternative.
More commonly, and as well established by prior art, non-ferrous metal sulphides can bf3 dissolved in acidic sulphate solutions. Such solutions can be formed directly WO 93/08310 PCT/AU92/00570 3 from sulphuric acid, by bacterial regeneration of ferric sulphate solutions, or more commonly by the oxygen pressure leaching technology.
U.S. Patents 4,244,732 (Reynolds), 4,244,735 (Reynolds) and 4,331,469 (Kunda), all provide for disposal of arsenic in feed materials as an iron arsenic compound. However, these processes require pressure oxidation to operate in the sulphuric acid environment provided. These prior proposals are accordingly not cost effective and/or do not yield environmentally acceptable arsenic-containing by-products.
SUMMARY OF THE INVENTION It is accordingly an object of the present invention to provide, in one embodiment, a novel process suitable for the extraction or recovery of metal values from arsenic containing feeds. Such a novel process is preferably cost effective, maximizes metal recovery and yields environmentally acceptable arsenic-containing by-products.
The present invention accordingly provides, in one embodiment, a process suitable for the extraction or recovery of metal values from arsenic-containing feeds and including the steps of: treating the feed with a nitric acid-containing leachant solution in order to dissolve the desired metals; adding a source of iron (III) to the leachant solution whereby to oxidize arsenic (III) in solution to arsenic adding a neutralising agent to the leachant solution whereby to precipitate arsenic as arsenic separating the arsenic precipitate from the leachant solution; and recovering metal values from the leachant solution.
It has been found that the recovery step may be optionally carried out either before or after the solid/liquid separation step to remove the arsenic (V) precipitate.
The leachant solution is preferably nitric acid or an acidic solution containing dissolved oxides of nitrogen as the oxidant. Leachant solutions comprising nixtures such as WO 93/08310 PCT/AU92/00570 4 a nitric acid/sulphuric acid mix are also envisaged within the scope of the invention.
The leaching treatment step may be carried out at ambient temperatures and at atmospheric pressure. However it is preferred if the leaching treatment step is carried out at elevated temperatures. Temperatures in the range of 60-90°C are particularly preferred. The dissolution of the feed is generally mildly exothermic and the optimum temperature can be maintained by injection of steam and/or via heat exchangers. The leaching conditions are generally optimized to ensure complete oxidation of arsenic (III) to arsenic while providing reaction conditions that maximize precipitation of arsenic as stable ferric arsenate.
The source of iron (III) may be a salt such as ferric sulphate [Fe 2 (S0 4 3 or ferric nitrate [Fe(N0 3 3 or a compound s !h as pyrite [FeS 2 which generates iron (III) in solution j a the leachant solution.
The source of iron (III) may be added directly to the leachant solution during leaching treatment step In an alternative arrangement also within the scope of the present invention, the source of iron (III) may be added according to step to the leachant solution which comprises the liquid phase obtained from an initial solid/liquid separation step downstream of leaching treatment step This internmediate separation step allows the solid phase to be optionally leached for further extraction of metal values. A further optional suphuric acid leach step is particularly preferred.
The arsenic-iron precipitate is formed by the presence of a source of iron (III) such as ferric nitrate and by the addition of a neutralising agent such as calcium hydroxide.
Ferric arsenate precipitation is usually maximized at a pH of about 4-7, ie. slightly acidic. For some feeds, the liquor generated by the leaching treatment step will be considerably more acidic than this.
The iron (III) addition rate should preferably be WO 93/08310 PCT/AU92/00570 sufficient to achieve an Fe/As molar ratio of at least 4:1 and preferably about 8:1.
Lime is the commercially preferred neutralising agent in terms of cost and addition of calcium cations for precipitation of both arsenate and sulphate anions.
The neutralising agent may be added to the leachant solution at the same time as the source of iron (III). In one particularly preferred arrangement the source of iron (III) is added to the leachant solution during treatment step and the neutralising agent is added subsequently, most preferably to the liquid phase after an initial solid/liquid separation following leaching treatment step Preferably the precipitation of ferric arsenate is carried out at elevated temperatures preferably temperatures in the range of 80-85"C.
It has been found that the present invention results in the formation of a highly crystalline arsenic containing residue. The residue has high environmental stability and because of its highly crystalline structure the solid/liquid separation processes are improved.
In addition the invention has the advantage of utilizing a leachant solution which results in very short reaction times with the extent of dissolution of desired n ?tal values being maximized without the need for using pressures above atmospheric pressure.
The present invention is suitable for use as a pretreatment step wherein after removal of the arsenic from the circuit via the arsenic precipitate the leach liquor may be further treated to recover copper and/or other dissolved metals such as zinc, nickel and cobalt.
One particular advantage of the present invention is that it facilitates the extraction of metal values from a wide range of feeds including feeds containing iron compounds which are generally considered as refractory feeds.
The invention is particularly suitable for application to feeds containing zinc, copper, nickel, cobalt and platinum group metals.
WO 93/08310 PCY/AU92/0,0570 6 BRIEF DESCRIPTION OF THE DRAWINGS There are a number of flow-sheets which could be developed for each given feed. Examples of two such flowsheets suitable for treatment of a lead-containiig dross according to the present invention are shown in the drawings.
In the drawings: Figure 1 is a flow-sheet for a Nitrate/Sulphate treatment of a high arsenic lead dross feed; and Figure 2 is an alternative flow-sheet for a Nitrate :reatment of a high arsenic lead dross feed.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the nitrate/sulphate based option shown in Figure 1 the high arsenic lead dross feed is subjected to a nitric acid leach in the present of pyrite [FeS2] and ferric sulphate [Fe 2 ,(S0 4 3 In this particular embodiment of the invention the nitric acid leach which comprises treatment step is conducted at atmospheric pressure and at a temperature in the range of 85-90 0 C. The temperature is raised by the introduction of steam to the nitric acid leach treatment step. At least a portion of the nitric acid used for leaching can be supplied by the nitric acid recovery stage.
The nitric acid leach treatment step at elevated temperatures generates a variety of nitrogen oxides [NOx] which may be sent to the nitric acid recovery step.
This nitric acid regeneration step may consist of a conventional process using direct oxidation of the NOx gas stream and absorption into an aqueous stream. In an alternative regeneration step not included in Figure 1, nitric acid can be regenerated by treatment of a solution containing nitrate and chloride anions with sulphuric acid.
After initial leaching the contents of the leach vat are passed to a solid/liquid separation stage at which the solid material which contains the lead values are subject to an optional sulphuric acid leach followed by a further solid/liquid separation. The liquid phase from the separation is recycled to the nitric acid leach vat and the WO 93/08310 PCT/AU92/00570 7 solid phase provides the lead in the form of lead suphate [PbS04J which may be recovered as metallic lead if required.
The sulphuric acid used for the optional sulphuric acid leach step may be provided at least partly from the zinc recovery stage which is conducted downstream.
The liquid extract from the separation following the nitric acid leach contains the arsenic and iron in solution.
By the addition of calcium hydroxide (lime) which raises the pH to the preferred range of pH 4-7, the arsenic is precipitated as ferric arsenate [FeAs041. This stage is conducted preferably at a temperature in the region of 0 C. The precipitate is separated in a following solid/liquid separation stage and the ferric arsenate and iron residues are sent to waste disposal.
The liquid phase then passes to a copper recovery stage using for example a combination of solvent extraction and electrowinning. Any zinc in solution can also be recovered by such means. Nitric acid can be recovered from the copper and zinc-depleted liquors.
In the alternative embodiment shown in Figure 2 the arsenic containing lead dross undergoes nitric acid leach and separation without any optional sulphuric acid leach for removal of lead as lead sulphate.
After the lead dross containing arsenic undergoes nitric acid leach a solid liquid separation takes place and the liquid phase passes to the arsenic/iron precipitation stage where ferric nitrate [Fe(N0 3 3 and calcium hydroxide [Ca(OH) 2 are introduced to precipitate ferric arsenate which is removed along with iron residues in the following solid/liquid separation stage and sent to waste disposal.
Conditions are similar to those described above in terms of temperature, pressure, pH, Fe/As ratio etc. As will be appreciated by those skilled in the art, it is not practical to nominate specific conditions because each feed will yield process liquors of varying composition. Each feed must be treated on its own merits and optimized accordingly.
The liquid phase from this separation passes to a lead WO 93/08310 PCT/AU92/00570 8 precipitation stage where -arboi dioxide and calcium hydroxide ore introduced to precipicate the lead product which iE extracted from a further solid/liquid separation stage in known manner.
These two flow-sheets illustrate typical examples of the application of the present invention to a particular feed material.
While it has been convenient to describe the invention herein in relation to particularly preferred embodiments, it is to be appreciated that other constructions and arrangements are also considered as falling within the scope of the invention. Various modifications, alterations, variations and/or additions to the constructions and arrangements described herein are also considered as falling within the scope and ambit of the present invention.
Claims (16)
1. A process suitable for the extraction or recovery of non-ferrous metal values from arsenic containing feeds and including the steps of: treating the feed with a nitric acid-contairing leachant solution in order to dissolve the desired metals; adding a source of iron (111) to the leachant solution whereby to oxidise arsenic (III) in solution to arsenic adding a neutralising agent to the leachant solution whereby to precipitate arsenic as arsenic separating the arsenic precipitate from the leachant solution; and recovering said metal values from the leachant solution.
2. A process according to claim 1 wherein the recovery step is carried out subsequent to arsenic precipitate separation step
3. A process according to claim 1 wherein said leachant solution is nitric acid.
4. A process according to claim 1 wherein said leachant solution comprises an acidic solution containing dissolved oxides of nitrogen as oxidant. A process according to claim 1 wherein leaching treatment step is conducted at elevated temperatures in the range of from 60 to
6. A process according to claim 1, wherein at least leaching treatment step (a) is conducted at atmospheric pressure.
7. A process according to claim 1 wherein said source of iron (III) comprises ferric sulphate [Fe 2 (SO4)3] or ferric nitrate [Fe(NO 3 3
8. A processing according to claim 1 wherein said source of iron (II1) comprises pyrite (FeS 2 or a compound which generates iron (111) in said leachant solution.
9. A process according to claim 1 wherein said neutralising agent is added to said leachant solution whereby to facilitate precipitation of the arsenic-iron .L precipitate by IPEA/SUBSTITUT SH'.I' WO 93/08310 PCT/AU92/0070 adjusting the pH to a level of about 4-7. A process according to claim 1 wherein said neutralising agent comprises calcium hydroxide [Ca(OH) 2
11. A process according to claim 1 wherein ferric arsenate is precipitated at elevated temperatures.
12. A process according to claim 11 wherein said elevated temperatures are in the range of from 80 to 856C.
13. A process according to claim 1 wherein after leaching treatment step an initial separation is undertaken to form a solid phase and a liquid phase.
14. A process according to claim 13 wherein said source of iron (III) is added in step to said liquid phase. A process according to claim 13 wherein said neutralising agent is added in step to said liquid phase.
16. A process according to claim 1 wherein said feed is a high arsenic lead dross feed.
17. A process according to claim 16 wherein prior to precipitation step an initial solid/liquid separation step is conducted in which the solid phase which contains lead values is subjected to a sulphuric acid leach and the liquid phase from said separation undergoes precipitation according to step following by separation according to step and recovery according to step
18. A process according to claim 1 which further includes a nitric acid regeneration step in which nitrogen oxides [NOr] generated in step are recovered in the form of nitric acid which is recycled to step
19. A process according to claim 18 wherein nitric acid is regenerated in step by treatment of a solution containing nitrate and chloride anions with sulphuric acid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU28647/92A AU650802B2 (en) | 1991-10-25 | 1992-10-23 | Extraction or recovery of metal values |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPK910591 | 1991-10-25 | ||
| AUPK9105 | 1991-10-25 | ||
| PCT/AU1992/000570 WO1993008310A1 (en) | 1991-10-25 | 1992-10-23 | Extraction or recovery of metal values |
| AU28647/92A AU650802B2 (en) | 1991-10-25 | 1992-10-23 | Extraction or recovery of metal values |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2864792A AU2864792A (en) | 1993-05-21 |
| AU650802B2 true AU650802B2 (en) | 1994-06-30 |
Family
ID=25620782
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU28647/92A Ceased AU650802B2 (en) | 1991-10-25 | 1992-10-23 | Extraction or recovery of metal values |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU650802B2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU566135B2 (en) * | 1983-01-18 | 1987-10-08 | Sasox Processing Pty Ltd | Arsenopyrite nitric acid leach for gold recovery |
-
1992
- 1992-10-23 AU AU28647/92A patent/AU650802B2/en not_active Ceased
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU566135B2 (en) * | 1983-01-18 | 1987-10-08 | Sasox Processing Pty Ltd | Arsenopyrite nitric acid leach for gold recovery |
Also Published As
| Publication number | Publication date |
|---|---|
| AU2864792A (en) | 1993-05-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |