Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
The Amendment filed June 25, 2026, has been entered. Claims 1-11, 15-22 and 24 remain pending in the application. Applicant’s amendments to the Claims have overcome the rejection of claim 21 and 22 under 35 U.S.C. § 112(b) previously set forth in the previous Office Action mailed March 31, 2026. Therefore, the rejection has been withdrawn. However, claim 21 is objected to for informalities addressed below.
Response to Arguments
Applicant's arguments filed June 25, 2026 have been fully considered but they are not persuasive.
Applicant argues that the cited references were considered during the international stage and that the claims were found to possess inventive step. Applicant further argues that, although the individual components of Formula I and Formula II are separately disclosed by Birken and Smolko-Schvarzmayr, respectively, neither reference provides a suggestion to combine those components. Applicant additionally relies upon Tables F-1-1 and F-1-2 of the specification as evidence of unexpected results. These arguments have been fully considered but are not persuasive.
The determination made during the international stage is not controlling upon examination of the present U.S. application. The presently maintained rejection is based upon the teachings of the cited references as considered under the standards of 35 U.S.C. 103. In particular, Birken teaches fatty amidoamine collectors for beneficiation by flotation, including reverse flotation of silicate-containing ores and iron ores, and further contemplates use of its amidoamine collector with additional collector components. Smolko-Schvarzmayr expressly teaches that collector performance may be improved by using combinations of a primary collector and a secondary collector and identifies alcohol alkoxylates, including ethoxylates, as suitable secondary collectors. Thus, the rejection does not rely merely upon the fact that the respective components were independently known. Smolko-Schvarzmayr provides an express reason for employing alcohol ethoxylate as a secondary collector with a primary flotation collector, namely, to improve collector performance. The modification of Birken in accordance with Smolko-Schvarzmayr therefore arises from the teachings of the prior art itself rather than from Applicant’s disclosure. The further teachings of Martins reinforce that mixed collector systems employing amidoamines together with additional collector species were known in iron-ore flotation and were employed to improve flotation performance.
Applicant’s evidence concerning Tables F-1-1 and F-1-2 has also been considered. The data demonstrate improved iron recovery for certain particular combinations of the tested amidoamines and ethoxylates. However, evidence of improved performance does not, without more, establish that the improvement would have been unexpected to one of ordinary skill in the art. Smolko-Schvarzmayr expressly teaches that collector performance may be improved by combining a primary collector with a secondary collector and specifically teaches alcohol alkoxylates as secondary collectors. Thus, improvement resulting from addition of an alcohol ethoxylate secondary collector would have been reasonably suggested by the prior art. Moreover, the evidence is not commensurate in scope with the presently claimed subject matter. Claim 1 encompasses broad genera of Formula I amidoamines and Formula II ethoxylates, including Formula II compounds having RE groups extending from C10-C20 and degrees of ethoxylation from 1 to 12, without requiring the particular collector ratios, ore, dosage, pH, or other flotation conditions employed in the reported experiments. Claim 24 likewise broadly encompasses the Formula I/Formula II collector composition without requiring the particular experimentally tested species or proportions. By contrast, the reported experiments employ a limited number of particular amidoamines and ethoxylates under specific flotation conditions and at particular collector ratios. The specification itself identifies the ethoxylate as a secondary collector that “supports or boosts the performance of the amidoamine” further demonstrating that enhancement of collector performance is consistent with the contemplated function of the secondary collector.
Accordingly, while Applicant’s evidence has been considered and is recognized as demonstrating improved performance for certain test embodiments, the evidence is insufficient to establish unexpected results commensurate in scope with the presently claimed subject matter or to outweigh the evidence of obviousness presented by the prior art.
Claim Objections
Claim 21 objected to because of the following informalities: improper grammar. Specifically, claim 21 is objected to because of the informal recitation “The method according to any preceding claim 2.” The intended dependency appears to be claim 2, particularly because claim 21 further limits “step (b)”, which is recited in claim 2. Claim 21 should therefore be amended to recite “The method according to claim 2” for clarity and proper form. Appropriate correction is required.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-2 are rejected under 35 U.S.C. 103 as being unpatentable over Birken (US20140048454A1) in view of Smolko-Schvarzmayr (WO2016041916A1).
Regarding claim 1, Birken discloses a method for manufacturing a concentrate enriched in iron mineral content from an ore, which contains an iron mineral and silicate, by a reverse flotation (Birken pars. [0002], [0125] and [0127]), characterized that said method comprises the step of
(c) adding a collector composition comprising
(i) an amidoamine, which contains a compound of formula I
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(I), wherein R1 is a linear or branched aliphatic C7-C19 alkyl or a linear C7-C19 aliphatic alkenyl, R2 is a linear or branched aliphatic C2-C6 alkylene, R3 and R4 are independently from each other H, C1-C2 alkyl or a substituent of formula I-S
*-[-(CH2-)p-NH-]q-(-CH2-)p-NH2 (I-S), wherein p is 2, 3 or 4, q is 0, 1, 2 or 3, and * represents the connecting site of the substituent, or a salt of a protonated compound of formula I and an anion (Birken pars. [0027-0042] and claim 1 teaches formula 1 comprising many examples of amidoamines consisting of ranges of substituents which overlap and encompass the range of substituents indicated for formula 1 disclosed above) to a prepared aqueous pulp of the ore and optionally one or more flotation auxiliary (Birken par. [0070]) to obtain an aqueous mixture (Birken par. [0004] “Flotation process generally takes place in a cell containing an aqueous suspension of the ore to be treated, and a generator of air bubbles. At least one collector is added”).
Birken does not explicitly disclose that the collector composition further comprises
(ii) an ethoxylate, which contains a compound of formula II
RE-O-(-CH2-CH2-O-)n-H (II), wherein RE is a linear or mono-branched aliphatic C10-C20 alkyl or a linear aliphatic C10-C20 alkenyl, n is an integer from 1 to 12, to a prepared aqueous pulp of the ore and optionally one or more flotation auxiliary to obtain an aqueous mixture as presently recited. Rather, Birken teaches that its optional second collector is a compound of formula (2), including alkoxylated fatty polyamines and, more specifically, ethoxylated or propoxylated fatty diamines. Thus, Birken teaches the claimed reverse flotation iron-ore/amidoamine framework and even suggests a multi-component collector system but does not expressly disclose the alcohol ethoxylate second component of formula II.
Smolko-Schvarzmayr is directed to froth flotation collector systems employing a primary collector together with a secondary collector and expressly teaches that “collector performance may be improved by using collector combinations of a primary (main) collector and a secondary collector (co-collector),” and that the term “’collector composition’ shall be used to describe compositions containing both a primary and a secondary collector.” Smolko-Schvarzmayr further discloses a flotation process using a collector composition comprising a primary collector and a secondary collector which is selected from the group of branched fatty alcohols with 12-16 carbon atoms having a degree of branching of 1-3, and alkoxylates thereof with a degree of ethoxylation of up to 3 (Smolko-Schvarzmayr p. 3 par 2), with the secondary collector also described as branched fatty alcohols with 12-16 carbon atoms having a degree of branching of 1-3, and their alkoxylates with a degree of ethoxylation of up to 3 (Smolko-Schvarzmayr claim 1 and p. 4 showing formula I).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the reverse-flotation amidoamine collector method of Birken by employing, as the additional collector component, the known alcohol alkoxylate/ethoxylate secondary collector taught by Smolko-Schvarzmayr. Birken already teaches that its amidoamine collector may be used in reverse flotation of silicate-containing ores, is particularly efficient for iron ores, and may optionally be used with an additional collector component. Smolko-Schvarzmayr teaches in the same flotation art that collector performance may be improved through use of a primary collector together with a secondary collector and specifically teaches alcohol alkoxylates/ethoxylates as such secondary collectors.
A person of ordinary skill in the art would therefore have been motivated to select a known ethoxylated alcohol co-collector for use with Birken’s amidoamine collector in order to obtain the known benefits of multi-component collector systems, including improved flotation performance and froth behavior, while retaining Birken’s known suitability for reverse flotation of silicate-containing ores including iron ores. Smolko-Schvarzmayr expressly teaches that collector performance may be improved through the use of a primary collector together with a secondary collector and identifies alcohol alkoxylates/ethoxylates as suitable secondary collectors; therefore, the motivation to combine arises from the prior art itself and does not depend upon Applicant’s disclosure.
Regarding claim 2, Birken in view of Smolko-Schvarzmayr discloses the method according to claim 1, wherein the method comprises the steps of
(a) providing the ore, which contains an iron mineral and silicate (Birken claims 13, 20),
(b) preparing from the provided ore by addition of water and optionally one or more flotation auxiliaries an aqueous pulp (Birken pars. [0003] and claims 10, 12),
(c) adding the collector composition to the prepared aqueous pulp of the ore and optionally one or more flotation auxiliaries to obtain an aqueous mixture (Birken par. [0004], Smolko-Schvarzmayr claim 7 “collector composition”),
(d) aerating the aqueous mixture in a flotation cell to generate a froth, which is enriched in silicate content, and removing the generated froth from the flotation cell (Birken par. [0004]),
(e) obtaining from the flotation cell the concentrate enriched in iron mineral content (Birken claim 14 where reverse flotation leaves the ores of value behind after the impurities are floated away).
Regarding claim 21, Birken in view of Smolko-Schvarzmayr discloses the method according to claim 2, wherein at step (b) one or more flotation auxiliary is added and one of the flotation auxiliary is a depressing agent, a froth regulator, a co-collector or an extender oil (Birken teaches preparing the aqueous pulp with optionally one or more flotation auxiliaries; Smolko-Schvarzmayr p. 7 teaches that “Further flotation aids that may be present in the flotation process are depressants, such as a polysaccharide, alkalized starch or dextrin, extender oils, frothers/froth regulators”).
Claims 3-11, 15-20 and 24 are rejected under 35 U.S.C. 103 as being unpatentable over Birken (US20140048454A1) in view of Smolko-Schvarzmayr (WO2016041916A1) as applied to claim 1 above, and further in view of Martins (US-20140144290-A1).
Regarding claim 3, Birken in view of Smolko-Schvarzmayr discloses the method according to claims 1, wherein (i) the amidoamine contains different compounds of formula I, or salts of the protonated different compounds of formula I and an anion (Birken par. [0035] states formula I may also be used in the form of their addition salts with one or more acid and in par. [0071] also states “mixtures of compounds having various R1 radicals contain 16-18 carbon atoms”).
Birken in view of Smolko-Schvarzmayr does not expressly disclose that the ethoxylate contains different compounds of formula II.
Martins is directed to “mixed collector compositions” and teaches that using a collector composition containing a combination of one of more amidoamines and one of more etheramines in a separation process for the purification of iron containing ores yields a greater recovery of iron as compared to using a collector that contains the amidoamine or the etheramine alone, and further teaches that the amidoamines and etheramines can be combined with one another to form a collector that can include but is not limited to, the amidoamines of formula I and etheramines of formula IV and can be combined with varieties of these formulas with various listed substituents (Martins par. [0035]). Martins par. [0036] goes on to state that “collector composition can include, but is not limited to, about 1 wt.% to about 99 wt.% of the amidoamine of formula I and about 1 wt. % to about 99 wt. % of the etheramine of the Formula IV” teaching the desirability and known use in the same iron-ore flotation field of collector compositions employing plural different amidoamine-type and co-collector species together, rather than only a single species on each side.
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to employ, in the collector system of Birken in view of Smolko-Schvarzmayr, plural different amidoamine compounds of formula I and plural different ethoxylate compounds of formula II rather than only a single species of each. Birken already teaches a formula I amidoamine collector for reverse flotation of silicate-containing ores including iron ores and further teaches that collector performance may be improved by using collector combinations comprising a primary collector and a secondary collector, and its disclosure of secondary collectors embraces alkoxylates of branched fatty alcohols as a class rather than a single fixed species. Martins then reinforces that, in the same iron-ore flotation art, mixed collector compositions using one or more amidoamines together with one or more co-collector species were known to improve recovery relative to use of either collector alone. A person of ordinary skill in the art would therefore have been motivated to use variations of mixtures of the known formula I amidoamine collectors and known formula II-type ethoxylate co-collectors in order to optimize collector performance, selectivity, and recovery, which would have been no more than the predictable use of known alternative members of recognized collector classes in a known mixed-collector flotation system.
Regarding claim 4, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein (i) the amidoamine is obtainable by condensation of a fatty acid with an amine (Birken claim 3 and par. [0043-0045] “C16-C18 unsaturated fatty acid” and “1’” ).
Regarding claim 5, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein (ii) the ethoxylate is obtainable by ethoxylation of one equivalent of an alcohol of the formula II-AL RE-OH (II-AL), wherein RE is defined as in claim 1, with n equivalents of ethylene oxide, wherein n is defined as in claim 1. (Smolko-Schvarzmayr claims 1 and 2 with Formula (I) teaches an alcohol alkoxylate/ethoxylate made from an alcohol backbone with ethylene oxide units and therefore renders the added ethoxylation limitation obvious for the secondary collector already used).
Regarding claim 6, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein the collector composition comprises (i) an amidoamine, which contains a compound of formula I
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(I), wherein R1 is a linear or branched aliphatic C11-C19 alkyl or a linear C11-C19 aliphatic alkenyl, R2 is a linear or branched aliphatic C2-C6 alkylene, R3 and R4 are independently from each other H, C1-C2 alkyl or a substituent of formula I-S
*-[-(CH2-)p-NH-]q-(-CH2-)p-NH2 (I-S), wherein p is 2, 3 or 4, q is 0, 1, 2 or 3, and * represents the connecting site of the substituent, or a salt of a protonated compound of formula I and an anion (Birken pars. [0027-0042] and claim 1 teaches formula 1 comprising many examples of amidoamines which overlap and encompass the framework of formula 1 with the R groups disclosed above), and which is obtainable by condensation of a fatty acid of formula I-FA with an amine of formula I-A (Birken claim 3 and par. [0043-0045] “C16-C18 unsaturated fatty acid” and “1’” ) (ii) an ethoxylate, which contains a compound of formula II
RE-O-(-CH2-CH2-O-)n-H (II), wherein RE is a linear or mono-branched aliphatic C10-C20 alkyl or a linear aliphatic C10-C20 alkenyl, n is an integer from 1 to 12, and which is obtainable by ethoxylation of one equivalent of an alcohol of formula II-AL
RE-OH (II-AL) with n equivalents of ethylene oxide. (Smolko-Schvarzmayr claims 1 and 2 with Formula (I) teaches an alcohol alkoxylate/ethoxylate made from an alcohol backbone with ethylene oxide units and therefore renders the added ethoxylation limitation obvious for the secondary collector already used).
Regarding claim 7, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein the collector composition comprises more parts by weight of the amidoamine than of the ethoxylate, and the sum of the amidoamine and the ethoxylate is 100 parts by weight (Smolko-Schvarzmayr claim 5 teaches embodiments where the primary collector is present in a greater amount ranging between 15:85 to 99:1, it would be obvious to a person of ordinary skill that these ranges sum 100 parts by weight).
Regarding claim 8, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein the collector composition comprises (i) 65 to 99 parts by weight of the amidoamine, and (ii) 1 to 35 parts by weight of the ethoxylate, and the sum of the amidoamine and the ethoxylate is 100 parts by weight (Smolko-Schvarzmayr claim 5 teaches embodiments where the primary collector is present in at amounts ranging between 15:85 to 99:1 and p. 8 Example 1 specifically employs a 65:35 collector-mixture ration which falls exactly at the claimed boundary, it would be obvious to a person of ordinary skill that these ranges sum 100 parts by weight).
Regarding claim 9, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein the collector composition comprises (i) 75 to 99 parts by weight of the amidoamine, and (ii) 1 to 25 parts by weight of the ethoxylate, and the sum of the amidoamine and the ethoxylate is 100 parts by weight (Smolko-Schvarzmayr claim 5 teaches embodiments where the primary collector is present in at amounts ranging between 15:85 to 99:1 and the claimed narrower subrange represents an obvious optimization/selection from the broader disclosed ratio range in the same collector-combination art, it would be obvious to a person of ordinary skill that these ranges sum 100 parts by weight).
Regarding claim 10, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein the collector composition comprises (i) 85 to 99 parts by weight of the amidoamine, and (ii) 1 to 15 parts by weight of the ethoxylate, and the sum of the amidoamine and the ethoxylate is 100 parts by weight (Smolko-Schvarzmayr claim 5 teaches embodiments where the primary collector is present in at amounts ranging between 15:85 to 99:1 and the claimed narrower subrange represents an obvious optimization/selection from the broader disclosed ratio range in the same collector-combination art, it would be obvious to a person of ordinary skill that these ranges sum 100 parts by weight).
Regarding claim 11, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein (a) R3 is H or C1-C2 alkyl, (Birken Formula I R22/23 (R3) each independently represent a hydrocarbon group containing from 1 to 6 carbon atoms, encompassing this group of substituents) (b) p is 2 and q is 1, 2 or 3, (c) n is 1, 2, 3 or 4, (d) RE is a linear or mono-branched aliphatic C12-C18 alkyl or a linear aliphatic C18 alkenyl or any combination of (a) to (d).
Regarding claim 15, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein in case the ethoxylate contains only compounds of formula II with the same RE, the same RE is linear, or in case the ethoxylate contains compounds of formula II with two or more different RE, an average degree of branching of RE for all the compounds of formula II is between 0 and 0.8 (Smolko-Schvarzmayr p. 9 Table 1 expressly discloses both a linear alcohol ethoxylate secondary collector, “Alfol 12/14S + 1.5EO”, with “DB 0,” and also a “Mixture (linear/branched)” alcohol ethoxylate secondary collector, “Safol 23 + 1.5 EO,” with DB 0.6”; Smolko-Schvarzmayr further explains that linear alcohol ethoxylates were used in the flotation tests and compares them directly with branched alcohol ethoxylates teaching both linear and branching within the claimed range).
Regarding claim 16, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 15, wherein RE is linear (Smolko-Schvarzmayr p. 9 Table 1 expressly discloses a linear alcohol ethoxylate secondary collector, “Alfol 12/14S + 1.5EO”, with “DB 0,” with the type of alcohol as linear).
Regarding claim 17, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein the anion is C1-C18 carboxylate, fluoride, chloride, bromide, iodide, sulfonate, hydrogensulfate, sulfate, dihydrogenphosphate, hydrogenphosphate, phosphate, nitrate, hydrofluorosilicate or fluorosilicate. Birken par. [0035] teaches that the compounds of formula I may be used “in the form of their addition salts with one or more acid(s), said acid( s) being chosen from among mineral and organic acids, including but not limited to, hydrochloric acid, acetic acid, phosphoric acid, sulphuric acid, alkane (e.g. methane) sulphonic acid, toluene sulphonic acid, and the like” which teaches one of ordinary skill in the art the corresponding counteranions such as chloride from hydrochloric acid, carboxylate/acetate from acetic acid, sulfonate from alkane sulphonic acid and many other options of the anions listed above.
Regarding claim 18, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein the collector composition is added in an amount between 10 g to 500 g per ton of the ore (Smolko-Schvarzmayr p. 7 teaches the amount of collector composition in ranges preferably from 20 to 500 g/ton dry ore).
Regarding claim 19, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein the pH value at step (c) is between 8 and 12 (Smolko-Schvarzmayr p. 7 teaches the pH in a range within 8-11).
Regarding claim 20, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses the method according to claim 1, wherein the collector composition is added as an aqueous solution or suspension. (Smolko-Schvarzmayr p.10 Example 2 expressly teaches that a mixture of primary and secondary collectors added as a 1% aqueous solution)
Regarding claim 24, Birken in view of Smolko-Schvarzmayr and further in view of Martins discloses a collector composition, comprising: (i) an amidoamine, which contains a compound of formula I
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(I), wherein R1 is a linear or branched aliphatic C7-C19 alkyl or a linear C7-C19 aliphatic alkenyl, R2 is a linear or branched aliphatic C2-C6 alkylene, R3 and R4 are independently from each other H, C1-C2 alkyl or a substituent of formula I-S
*-[-(CH2-)p-NH-]q-(-CH2-)p-NH2 (I-S), wherein p is 2, 3 or 4, q is 0, 1, 2 or 3, and * represents the connecting site of the substituent, or a salt of a protonated compound of formula I and an anion (Birken pars. [0027-0042] and claim 1 teaches formula 1 comprising many examples of amidoamines consisting of ranges of substituents which overlap and encompass the range of substituents indicated for formula 1 disclosed above); (ii) an ethoxylate, which contains a compound of formula II
RE-O-(-CH2-CH2-O-)n-H (II), wherein RE is a linear or mono-branched aliphatic C10-C20 alkyl or a linear aliphatic C10-C20 alkenyl, n is an integer from 1 to 12 (Smolko-Schvarzmayr p. 3 par 2 teaches a flotation process using a collector composition comprising a secondary collector which is selected from the group of branched fatty alcohols with 12-16 carbon atoms having a degree of branching of 1-3, and alkoxylates thereof with a degree of ethoxylation of up to 3, with the secondary collector also described as branched fatty alcohols with 12-16 carbon atoms having a degree of branching of 1-3, and their alkoxylates with a degree of ethoxylation of up to 3 (Smolko-Schvarzmayr claim 1 and p. 4 showing formula I).
Claim 22 is rejected under 35 U.S.C. 103 as being unpatentable over Birken (US20140048454A1) in view of Smolko-Schvarzmayr (WO2016041916A1) as applied to claim 21 above, and further in view of Svensson (WO-2000062937-A1).
Regarding claim 22, Birken in view of Smolko-Schvarzmayr discloses the method according to claim 21.
Birken in view of Smolko-Schvarzmayr does not explicitly disclose that the depressing agent added is specifically starch. Although Smolko-Schvarzmayr identifies alkalized starch as a known depressant, Birken does not expressly demonstrate use of starch as the depressing agent in its iron-ore reverse-flotation process.
Svensson is directed to “froth flotation of silicates from an iron ore” and expressly teaches the use of a depressing agent during preparation of the aqueous pulp of an iron ore. Svensson (p. 4) states that after the ground ore is suspended in water and deslimed, “an aqueous water slurry (pulp) is prepared from the deslimed ore and a depressing agent for the iron ore is normally added” and further teaches that the “depressing agent could be a hydrophilic polysaccharide, e.g. starch, such as corn starch activated by treatment with alkali and dextrin”. Svensson further expressly demonstrates this sequence in Example 1, wherein an aqueous pulp of hematite ore is prepared and after “addition of 500 mg of starch treated with alkali per kg ore the pulp was conditioned for 5 minutes” after which the pH is adjusted, a collector is added, and reverse flotation produces “a silicate-rich froth product and an iron-rich bottom concentrate”.
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to employ starch as the depressing agent in the method of Birken in view of Smolko-Schvarzmayr. Smolko-Schvarzmayr already teaches that depressants, including alkalized starch, are conventional flotation auxiliaries, thereby suggesting starch as a suitable member of the depressant class recited in claim 21. Svensson further teaches in the closely analogous context of reverse flotation of silicate-containing iron ore that starch is conventionally added to the aqueous ore pulp as a depressing agent before addition of the collector, thereby providing an express art-recognized reason and process sequence for its use. A person of ordinary skill in the art would therefore have been motivated to select starch as the depressing agent in the established Birken/Smolko-Schvarzmayr process for its known function of depressing the iron mineral while permitting preferential flotation of silicate, with a reasonable expectation of obtaining an iron-rich bottom concentrate and silicate-rich froth as taught by Svensson.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to WILLIAM ADDISON GEISBERT whose telephone number is (703)756-5497. The examiner can normally be reached Mon-Fri 7:30-5:00 EDT.
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/W.A.G./Examiner, Art Unit 1779
/Bobby Ramdhanie/Supervisory Patent Examiner, Art Unit 1779
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