AU626155B2 - Titanium agglomerates - Google Patents

Abstract

A process for increasing the particle size of fines of a titaniferous mineral containing more than 45 % by weight of titanium. The process comprises mixing the fines with a binding agent and water to produce an agglomerate. The agglomerate is then dried and sintered.

Description

I OPI DATE 19/02/90 APPLN. ID 39897 89 AOJP DATE 29 3/ PC N E f CT/AU89/00514 INTERNATIONAL APPLICATION, B MEBjZNDIR RTI PA T COOPERATION TREATY (PCT) (51) International Patent Classification 4 (11) International Publication Number: WO 90/01072 C22B 1/1 Al (43) International Publication Date: 8 February 1990 (08.02.90) (21) International Application Number: PCT/AU89/00314 (74) Agent: GRIFFITH HACK CO.; 2nd Floor, 601 St. Kilda Road, Melbourne, VIC 3004 (AU).

(22) International Filing Date: 25 July 1989 (25.07.89) (81) Designated States: AT (European patent), AU, BE (Euro- Priority data: pean patent), BF (OAPI patent), BJ (OA?I patent), BR, PI 9487 26 July 1988 (26.07.88) AU CF (OAPI patent), CG (OAPI patent), CH (European patent), CM (OAPI patent), DE, DE (European patent), FR (European patent), GA (OAPI patent), GB, GB (Eu- (71) Applicant (for all designated States except US): COMMON- ropean patent), IT (European patent), JP, KR, LU (Eu- WEALTH SCIENTIFIC INDUSTRIAL RE- ropean patent), MG, ML (OAPI patent), MR (OAPI pa- SEARCH ORGANISATION [AU/AU]; Limestone tent), NL (European patent), SE (European patent), SN Avenue, Campbell, Canberra, ACT 2600 (OAPI patent), SU, TD (OAPI patent), TG (OAPI patent), US.

(72) Inventowr; and Inventors/Applicants (for US only) HALL, John, Sydney [AU/AU]; 24 Mayfield Avenue, Malvern, VIC 3144 Published CAREY, Ken, George [GB/AU]; 5 Beltana Court, With international search report.

Bayswater, VIC 3153 HOLLITT, Michael, John [AU/AU]; Wimmera Industrial Minerals Pty. Limited, 2nd Floor, 15 Bank Street, South Melbourne, VIC 3205

(AU).

(54) Title: TITANIUM AGGLOMERATES (57) Abstract A process for increasing the average particle size of a titaniferous mineral. The process comprises mixing fines of the mineral with a binding agent and water to form a mixture. The mixture is impacted and sheared to produce a micro-agglomerate which is then dried.

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f le "i __~7U VOIw 90/01072 PCT/A U89/00314 1 TITANIUM AGGLOMERATES The present invention relates to processes for making agglomerates of titanium-bearing particles and to processes for the preparation of upgraded products therefrom.

In processes for upgrading titanium bearing minerals, the objective is the removal of impurities, especially iron compounds, with associated increase in proportion of contained titania. The upgraded titania product in these cases would represent a useful feed to either acid digestion or carbochlorination as the first steps in the production of titania pigments.

i -i WO 90/01072 PCT/AU89/00314 -2- In processes for the production of titania pigments the primary step is chemical reaction to produce an intermediate product (titanium sulphates or chlorides in aqueous solution or liquid titanium tetrachloride).

Many of the elements associated with the titania in the feed, and especially any iron which is present, also become involved in the reaction and consume the active reagent (acid or chlorine). This reaction of associated elements has the economic penalty of excessive reagent consumption in primary reactions, and the economic and environmental penalties associated with separation of valuable titanium compounds from impurity compounds and the disposal of separated wastes.

Prior art processes exist for the upgrading of titanium bearing minerals to products containing relatively high levels of contained titanium dioxide (greater than 75% titania expressed as Ti0 2 The most advantageous of these processes utilise elevated temperature oxidation and reduction of titania feedstocks prior to removal of contained iron values by a method which does not consume appreciable quantities of chemical reagents overall. In such methods (with the exception of those based on mineral smelting to slag) the elevated temperature treatment involves contacting of solid particulate minerals with hot gases. Typically the contacting device is a fluidised bed or a kiln (e.g.

grate or rotary) in which the mineral residence time is appreciable several hours) In processes for gas/solids contacting there are necessarily practical limitations on minimum and maximum feed particle sizes. Fine particles will be entrained with exit gases and thus have short residence times. Coarse particles will require excessively long residence times for desired transfer of matter and heat to and from the contacting gases. In prior art processes for upgrading of titania minerals coarse natural titania

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WO 90/01072 PCF/AU89/00314 mineralisation larger than 0.5 mm in average particle diameter) has not been encountered. However, the practical limitation on minimum particle size in these processes is usually about 50-100m. The minimum particle size limitation for feeds to titania mineral upgrading processes has severely limited the usefulness of some mineral sources in these processes.

The most common type of mineral which is fed to upgrading processes is generically termed "ilmenite". In general usage the term ilmenite refers to iron bearing titaniferous minerals which may structurally include true ilmenite, pseudobrookite, pseudorutile, titanomagnetite and rutile. Ilmenite occurs naturally in sand and rock deposits, and is frequently fine grained. Fine grained ilmenite cannot be treated in gas/solid contacting devices forming part of the prior art upgrading processes.

An attempt to alleviate the difficulties posed by fine grained rock ilmenite in upgrading processes has been recorded in prior art literature. In this case, fine grained ilmenite was agglomerated in a balling drum to competent nodules having a coarse average particle size (2-5mm), as a pretreatment for reduction of contained iron to metal in a rotary kiln. However, the technique described is capable of producing only relatively coarse nodules and has the effect of ensuring a coarse reduced product. Such coarse products are not suited to fluid bed treatment or subsequent removal of iron using aqueous chemicals, and have only been applied to the smelting technique of upgrading. The ability to produce agglomerates of any desired average particle size, particularly at an average size of less than 2mm has not been demonstrated in the prior art.

N P 1 r: RECEIVED 09 AU G6jQ S-4- 8 9 /O O J4 It is the object of the present invention to overcome one or more of the perceived difficulties in Ahe flexible preparation of fine grained titanium-bearing materials for upgrading.

Accordingly, in a first aspect of the present invention there is provided a process for providing a titaniferous mineral of improved particle size which process comprises mixing fine mineral with a binding agent and water to form a mixture, subjecting the mixture to a high intensity impacting and shearing action to produce a micro-agglomerate, and drying the micro-agglomerate.

The source of titanium-containing mineral may be any titanium-containing mineral which is chemically suited to upgrading. The titanium-containing mineral may be natural or synthetic in origin. The titanium-containing mineral may be a detrital mineral.

The titanium may be present in the titanium-containing mineral in the form of titanium dioxide. The titanium-containing mineral may contain up to 20 per cent of grains which have little contained titanium.

The amount of water added may vary depending upon the size distribution of the original particles of the titanium-containing mineral and the required size of the agglomerated product. The amount of water may vary 4 from approximately 5 to 17% by weight, preferably 10-12% by weight, based on the total weight of titanium-containing mineral, binder and water.

The binder or binders for the titanium-containing particles may be of any suitable type. The binders for the titanium-containing particles should be such as to form agglomerates, also known as micro-agglomerates, which are capable of withstanding the physical, chemical and thermal degradation forces in drying and any subsequent thermal treatment processes, including gas/solids contacting. The binders may be organic or inorganic binders. The binders may be ceramic SUBSTIUTE SELT 2 WO 90/01072 PCr/AU89/00314 5 or glass-forming binders. The binders may be carbon-free binders. A single binder may be used. A combination of two or more binders may be used to provide strength under the different operating environments of the drying and subsequent treatment stages.

The binder for the titanium-containing minerals may be such that it does not seriously contaminate the bound titanium bearing particles for subsequent processing, for example in upgrading processing.

The binder for the titanium-containing particles may include: 1) Colloidal silica 2) Silica, water soluble silicates or silica/fluoride mixtures 3) Clay miners (including bentonite, kaolinite and montmorillonite) 4) Boehmite Boehmite/silica mixture 6) Goethite 7) Lignosulphonate 8) Sodium carbonate (saturated solution) 9) Sodium silicate Group II carbonate/clay mineral mixture 11) Sugars e.g. molasses 12) Aluminium salt/organic amide mixtures 13) Titanium bearing organic and inorganic solutions 14) Polyvinyl acetate 15) Water emulsified organic binders.

The amount of binder for titanium-containing particles in the micro-agglomerate should ideally be sufficient to produce a strong competent micro-agglomerate. The amount of binder should preferably not be sufficient to encapsulate the i WO 90/01072 PCT/AU89/00314 6 titanium-containing particles. A relatively low percentage of binder is preferred. Percentages in the range of approximately 0.5 5% by weight are preferred.

The impacting and shearing step in the process of the present invention is advantageously conducted in devices incorporating an impaction/shearing action such as high intensity micro-agglomerators having high speed blades such that blade tip speed is in the range 50 1000m sec. l. This high intensity action may optionally be coupled directly or indirectly with a rolling/tumbling action, although a key feature of the present invention is the incorporation of the high intensity action.

Agglomeration may be conducted in stages or in closed circuit with product sizing screens.

The drying step may be conducted at elevated temperatures. Optionally where agglomeration of a moist product is to be conducted directly prior to a processing step involving heat treatment, a separate drying step may not be necessary. The drying step may be conducted at elevated temperatures from 75 to 100 C. The drying step is preferably carried out in such a manner as to limit the residence time of the micro-agglomerates in this part of the process to less than 30 minutes.

The drying step may be conducted in any suitable drying apparatus. A fluidised bed dryer or rotary dryer may be used.

The agglomerated particles, also called micro-agglomerates, may be manufactured to fall within a preferred size range to suit the dynamic requirements of gas/solids contacting devices. In most such devices it will be advantageous if the weight averaged particle size for the agglomerated product is coarser than 100m diameter. It is also advantageous for many high temperature physical and chemical processing operations if the average agglomerate particle size is less than 2mm diameter. J.

if WO 90/01072 PCT/AU89/00314 7 In a further aspect of the present invention there is provided a micro-agglomerate comprising 95 to 99.5% by weight of fine particles of a titaniferous mineral bound together with 0.5% to 5% by weight of a binding agent wherein titaniferous mineral has an average particle size in the range from 0.05 to 100 m and the micro-agglomerate has an average particle size in the range from 100pm to 2mm.

In a further aspect of the present invention the agglomeration process as disclosed herein may be used for the incorporation of desired additives having beneficial chemical or physical effects in subsequent gas/solids contacting steps or with the effect of imparting a particular physical or chemical property to upgraded products formed from titanium bearing minerals.

In particular the presently disclosed process, by virtue of the high intensity nature of the agglomeration step, is effective in ensuring highly homogeneous incorporation of powdered additives.

In a still further aspect of the present invention which is preferred for some titania mineral feeds, the process may include the preliminary step of grinding at least a portion of the titanium-containin particle source. The preliminary grinding step may be utilized to improve the size control in the preparation of the micro-agglomerates and thus provide the finished product with a greater strength and density. The titanium-containing particles may be introduced into any suitable grinder. A ball mill or rod mill may be used.

Hammer or ring mills may also be used.

The amount of titanium-containing feed to be ground may vary from zero to approximately 100% by weight depending on the source and type of titanium-containing ore. The grinding step may provide particles having an average size from approximately 5pm to approximately 100m.

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WO 90/01072 PCT/AU89/00314 -8 The moist or dried product of agglomeration may optionally be treated in a high temperature firing step to produce a granular titanium-containing product of sufficient strength for storage, handling and transportation, or treatment in a subsequent upgrading process, without appreciable degradation. Alternatively the high temperature gas/solids contacting step of the upgrading process may be used to simultaneously fire the agglomerated product.

In the optional firing step the temperature and residence time should be sufficient to produce homogeneous or heterogenous phase bonding between the particles within the micro-agglomerates. The micro-agglomerates may be heated to a temperature of approximately 900 0 C to 1500 0 C, preferably 1000 0 C to 1200 0 C. The residence time of the micro-agglomerates within the temperature range may be for a period of several minutes to approximately 10 hours. Significant chemical and physical changes may occur in the firing step. Additives incorporated into the agglomerates in the agglomeration step may become dissolved in or react with titanium bearing particles in the firing step.

Reduction or oxidation reactions may be carried out in the firing step. Iron contained within the titanium bearing particles may be reduced to the ferrous oxidation state or to metallic iron. Titanium dioxide may be reduced to form phases containing more reduced titanium oxides.

The firing step may be carried out by any suitable means, including a fluidised bed, in an oven or kiln. Heat may be applied by combustion of coal, fuel oil, natural gas or any other suitable fuel. Fuel combustion may be carried out with or without addition of oxygen, or oxygen enrichment or combustion air. Where reduction reactions are desired during firing solid carbon sources or gaseous reductants may be used.

d Ssi WO 90/01072 pCT/AU89/00314 9 In addition there is provided within the present invention a titanium-containing material formed according to the preparation process described above.

The titanium bearing material so formed may include a plurality of sintered micro-agglomerated particles. The bond formed between the titanium-containing particles may include particle boundary recrystallisation wherein the boundaries of the titanium containing particles may be physically merged.

The bond formed between the titanium-containing particles may also consist of a separate bridging phase formed by the binder or product phases formed by chemical reaction in a firing or curing step. The operation of a firing step may tend to eliminate the binder from the micro-agglomerated particles by evaporation, gasification or combustion. Further, the initially added binder may be present in the titanium bearing agglomerated product and/or may be incorporated in whole or in part in crystalline phases forming the product.

The titanium bearing granules so formed may optionally be subjected to further treatment after heat curing. In one form the heat cured granules may be subjected to subsequent classical treatment to upgrade the titanium content. The granules may be provided with sufficient strength to withstand the subsequent chemical treatment.

Alternatively the heat cured granules may be provided with only sufficient strength to withstand a firing process. The granules may then be easily degraded during further processing treatment, for example for removal of contained metallic iron, such that a liberated fraction of contaminant grains may then be removed. The granules may be degraded physically or chemically for this purpose.

i WO 90/01072 PCT/AU89/00314 10 The present invention will now be more fully described with reference to the accompanying examples.

It should be understood, however, that the description following is illustrative only and should not be taken in any way as a restriction on the generality of the invention described above.

Example 1 Agglomerates were prepared from an ilmenite mineral fraction derived from a mineral sands deposit located near Horsham in Western Victoria. The ilmenite mineral consisted of fine sand in the size range 45um to A laboratory scale batch Patterson-Kelley high intensity blender was used initially to blend a dry mixture of 9 kg of the ilmenite with 1% of -50pm ilmenite fines and 0.7% bentonite binder for two minutes. Water containing 1% PVA was then added at a controlled rate by spraying through a rotating central shaft within the blender on which was mounted high soeed mixing blades.

(The central shaft is known as an "intensifier bar").

The intensifier bar rotated at a speed of 1500-3000 rpm, serving both to shear the solids and to spray the water into the charge in a finely divided and well distributed form. The amount of water added in this way was 15% on a wet weight basis. The blender was allowed to continue to act on the charge for a further minute after completion of water addition, which required about four minutes.

The product was then discharged on to a large tray and oven-dried at 80 C for 48 hours to ensure that drying was complete.

Sizing analysis on the agglomerated product provided the following distribution: I Id 11 j r WO 90/01072 PCT/AU89/00314 11 Size range (diameter) mm 0.71 1.00 69.4 0.50 0.71 30.6 Dry agglomerate strength was assessed using a load cell to determine the force withstood to the point of failure, and this force averaged 0.llN over 30 tests.

Dry agglomerates were mixed with powdered charcoal and then fired in a muffle furnace at 1150°C for 5 hours. Breakage force after firing was on average 0.28N.

Fired, reduced agglomerates were leached with sulphuric acid solution for removal of metallic iron formed in reduction. During leaching the application of light agitation resulted in disintegration of the agglomerates to individual grains corresponding to the original ilmenite grains.

Microscopic examination of the reduced product revealed that bonds between individual grains consisted in large part of metallic iron formed in reduction.

Removal of this metallic iron in leaching had resulted in an upgrading of the product titania content and disintegration of agglomerates to individually liberated grains. Removal of impurity grains in the original mineral (for example, silicate or spinel grains) is consequently possible after the upgrading step.

Example 2 Agglomerates were prepared in identical manner to that described in Example 1, with the exception that 2% bentonite rather than 0.7% was used in the original blended mix.

Size analysis of the product gave the following distribution: J it i: WO 90/01072 PCI/AU89/00314 12 Size range 0.71 1.00 71.2 0.50 0.71 28.8 The dry agglomerates exhibited an average strength which could withstand 0.28N loading. Subsequent V reduction firing as in Example 1 resulted in an average breaking force of 1.46N.

After firing and leaching of these agglomerates disintegration did not occur. Consequently, material produced according to this method may be applied to applications for which a coarse product is desired, for example in dry handling or in gas/solids contacting as would be carried out in chlorination for titanium tetrachloride formation.

Example 3 Firing of dry agglomerates prepared according to the method described in Example 1 was carried out in the absence of reductant, in air at 1150 C for five hours in a muffle furnace. The fired product agglomerates exhibited strengths which could withstand an average loading of 3.7N. The fired product exhibited considerable bridging between particles and was highly suited for processing operations involving gas/solids contacting.

Example 4 Agglomerates were prepared from the 54% TiO 2 Horsham ilmenite according to the manner described in Example i. A sample of 400g of the agglomerates was admixed with 400g of Victorian brown coal char and fired in a high temperature steel crucible in a muffle furnace for two hours at 1180 0

C.

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WO 90/01072 PCT/AU89/00314 13 The fired reduced agglomerates were allowed to cool, were separated from the residual char, and were then added to 1.8L of water at 50 0 C, containing 1% ammonium chloride. Air was introduced to the mixture at 500 cc/min over a ten hour period whilst strongly agitating the mixture. Ilmenite and contaminant particles were completely liberated by disintegration of the agglomerates during the "rusting" step.

The disintegrated agglomerates from which fine iron oxides had been removed contained 84.2% TiO 2 After removal of 10% of liberated magnetic grains the disintegrated product contained 87.3% TiO 2 Example 1 kg of +0.5 0.71mm fired agglomerates prepared according to the method described in Example 3 were reduced at 1000 C in a fluidised bed of Victorian brown coal char. Fluidisation was maintained by passage of a 50% CO, 50% H 2 gas mixture at a superficial velocity -1 of 0.3 m.sec through the fluidised bed. Batch fluidised bed reduction in this manner was carried out for four hours, at the end of which time the bed was allowed to cool to room temperature. The degree of metallisation of contained iron in the agglomerates after reduction was 94.7%.

While significant agglomerate degradation occurred during the fluid bed reduction the reduced product retained an average particle size of 250pm, which is still considerably larger than the average original ilmenite particle size of 55pm. Product losses from the fluidised bed were negligible. Consequently, the agglomerated product has been shown to be suited for use in conventional gas/solids contacting devices by this example.

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Claims (13)

1. A process for providing a titaniferous mil eral of improved particle size which process comprises mixing fine mineral with a binding agent and water, subjecting the mixture to a high intensity impacting and shearing action to produce a micro-agglomerate, and drying the micro-agglomerate.

2. A process according to Claim 1 wherein the binding agent comprises from 0.5% to 5% of the mixture on a dry weight bases.

3. A process according to either Claim 1 or Claim 2 wherein the binder is capable of forming a glass or of exhibiting ceramic sintering properties when the micro-agglomerate is fired.

4. A process according to either Claim 1 or Claim 2, wherein the binding agent is selected from the group consisting of colloidal silica, silica, water soluble silicates or silica/fluoride mixtures, clay minerals including bentonite, kaolinite and montmorillonite, boehmite, boehmite/silica mixture, geothite, lignosulphonate, sodium carbonate, sodium silicate, Group II carbonate/clay mineral mixture, sugar, molasses, aluminium salt/organic amide mixtures, titanium bearing organic and inorganic solutions and polyvlnyl acetate. A process according to Claim 1 or Claim 2, wherein the binding agent is bentonite.

6. A process according to any one of Claims 1 to 4, including the additional step of firing the micro-agglomerate.

7. A process according to Claim 6, wherein the micro-agglomerate is fired at a temperature in the range from 900 to 1500 0 C.

8. A process according to Claim 7, wherein the firing temperature lies in the range from 1000 to 1200 0 C. SUBSTITUTE SH|1 C 15

9. A process according to any one of Claims 1 to 8, wherein the quantity of water added lies in the range from to 17% by weight of the mineral, the bentonite and the water. A process according to any one of Claims 1 to 8 wherein the quantity of water comprises from 10 to 12% by weight of the total weight of the mineral, the binding agent and the water.

11. A process according to any one of Claims 1 to wherein the titaniferous mineral is ilmenite.

12. A process according to anyone of Claims 1 to wherein the titaniferous mineral contains at least 35% by weight of titanium.

13. A micro-agglomerate produced according to the process of any one of Claims 1 to 12.

14. A micro-agglomerate produced according to the process of any one of claims 1 to 12 and comprising 95 to 99.5% by weight of fine particles of a titaniferous mineral bound together with 0.5% to 5% by weight of a binding agent wherein the particles of titaniferous mineral have an average particle size in the range from 0.05 to 100mum and the micro-agglomerate has an averge particle size in the range from 100pm to 2mm. S 15. A micro-agglome.rate according to Claim 14, wherein the binding agent is selected from the group consisting of colloidal silica, silica, water soluble silicates or silica/fluoride mixtures, clay minerals including bentonite, kaolinite and montmorillonite, boehmite, boehmite/silica mixture, geothite, lignosulphonate, sodium carbonate, sodium silicate, Group II carbonante/clay mineral mixture, sugar, molasses, aluminium salt/organic amide mixtures, titanium bearing organic and inorganic solutions and polyvinyl acetate.

56. A micro-agglomerate according to either Claim 14 or Claim 15, wherein the titaniferous mineral is ilmenite. I 0F, PC/A U89/00314 WO 90/01072 16 17. A micro-agglomerate according to either Claim 14 or Claim 15, wherein the titaniferous mineral is one containing at least 50% titanium. 18. A micro-agglomerate according to any one Claims 14 to 17, wherein the micro-agglomerate has been sintered or wherein the particles comprising the micro-agglomerate have been fusion bonded. 19. A micro-agglomerate according to Claim 18, wherein the micro-agglomerate has an average particle size lying in the range from 100 to 500um. 3?S41 0 A micro-agglomerate according to Claim 18, wherein the micro-agglomerate has an average particle size lying in the range from 150 to 250pm. i j V -$p :31I- INTERNATIONAL SEARCH REPORT International Application No. PCT/AU 89/00314 I. CLASSIFICATION OF SUBJECT MATTE (if several classification symbols apply, indicate all) 6 According to International Patent CLassification (IPC) or to both National CLassification and IPC Int. Cl. C22B 1/16 II. FIELDS SEARCHED I Minimum Documentation Searched 7 SClassification System Classification Symbols SIPC C22B 1/16, 1/243, 1/244 Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included in the Fields Searched 8 AU: IPC as above III. DOCUMENTS CONSIDERED TO BE RELEVANT 9 Category* Citation of Document, with indication, where appropriate, Relevant to of the relevant passages 12 Claim No 13 X US,A,4187117 (GUEGUIN) 5 February 1980 (05.02.80). See col. 3 l;ns I (1-13) S39-54, col. 4 lines 16-14 and 41-49. X AU,B,60020/69 (442320) (INTERNATIONAL MINERALS CHEMICALS CORP.) (1,6,9-13) S4 March 1971 (04.03.71). See page 8 lines 1-4, page 11 lines 13-28, Spage 12 lines 13-22 and page 14. X AU,A,29727/67 (MONSANTO CHEMICALS LTD.) 22 May 1969 (22.05.69). See (1-4,6,9,10) Spage 4 lines 28-29, claims. A I US,A,3961005 (SPARKS) 1 June 1976 (01.06.76). A GB,A,2199573 (CRA SERVICES LTD.) 13 July 1988 (13.07.88) A GB,A,2028787 (FOSECO INTERNATIONAL LTD.) 12 March 1980 (12.03.80) Special categories of cited documents: 10 later document published after the international filing date or priority date document defining the general state of the and not in conflict with the application but art which is not considered to be of cited to understand the principle or theory particular relevance underlying the invention "E earlier document but published on or document of particular relevance: the after the international filing date claimed invention cannot be considered novel document which may throw doubts on priority or cannot be considered to involve an claim(s) or which is cited to establish the inventive step publication date of another citation or document of particular relevance; the other special reason (as specified) claimed invention cannot be considered to document referring to an oral disclosure, involve an inventive step when the document use, exhibition or other means is combined with one or more other such document published prior to the documents, such combination being obvious to international filing date but later than a person skilled in the art. the priority date claimed document member of the same patent family IV. CERTIFICATION SDate of the Actual Completion of the Date of Mailing of this InternationaC" International Search Search Report 6 November 1989 (06.11.89) Qi. I C SInternational Searching Authority Signature of Authorized OfficAr SAustralian Patent Office B. BOURKE 8 J ANNEX TO THE INTERNATIONAL SEARCH REPORT ON INTERNATIONAL APPLICATION NO. PCrAU T900314 This Annex lists the known publication level patent family members relating to the patent documents cited in the above-mentioned internation search report. The Australian Patent Office is in no way liable for these particulars which are merely given for the purpoe of information. Patent Document Cited in Search Patent Family Members Report AU 60020/69 BR 6912088 DE 1945341 FR 2017389 GB 1276022 NL 6913414 US 3644113 US 3860414 AU 29727/67 DE 1583185 GB 1152614 GB 1288377 GB 1399815 US 4072065 US 4187117 BR 7702086 CA 1106141 TN 145890 NO 771159 US 4117076 US 3961005 CA 949331 GB 2028787 AU 49835/79 JP 55031194 GB 2199573 AU 81949/87 BR 8706886 CN 87108130 DE 3743096 FR 2608582 GB 2199573 ZA 8709179 END OF ANNEX