|Publication number||US3450257 A|
|Publication date||Jun 17, 1969|
|Filing date||Nov 15, 1967|
|Priority date||Mar 2, 1964|
|Publication number||US 3450257 A, US 3450257A, US-A-3450257, US3450257 A, US3450257A|
|Inventors||Edwin Kenneth Cundy|
|Original Assignee||English Clays Lovering Pochin|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (13), Referenced by (62), Classifications (17)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent US. Cl. 209 4 Claims ABSTRACT OF THE DISCLOSURE A method of removing titanium mineral impurities from a clay containing at least 40% by weight of particles smaller than 2 microns equivalent spherical diameter which comprises conditioning the clay at a solids content of at least 30% by weight for a time suflicient to dissipate therein at least 25 horsepower hours of energy per ton of solids and thereafter subjecting the clay to a froth flotation process in the presence of an activator consisting of a water-soluble salt of an alkaline earth metal or a heavy metal.
BACKGROUND OF THE INVENTION This is a continuatiou-in-part of application Ser. No. 435,340 filed Feb. 25, 1965 and now abandoned.
This invention relates to the processing of clays, of which kaolin and china clay are examples, containing at least 40% by Weight of particles smaller than 2 microns equivalent spherical diameter, and is more particularly concerned with a method of treating such clays to improve the brightness thereof by removing titanium mineral impurities therefrom.
Titanium mineral impurities occur in some clays as mined and, if they are colored, they detract from the appearance of the clay. It has previously been proposed to remove impurities by forming a suspension, or slurry, raising the pH of the slurry of the clay to an alkaline value, for example by the addition of ammonium hydroxide, and subjecting the slurry to a froth flotation process. In general the froth flotation process comprises adding a collector, for example oleic acid, to the alkaline slurry of the clay, conditioning the slurry by agitating the slurry in a tank for a time suflicient to dissipate therein about 5 to horsepower hours of energy per ton of solids, adding a frothing agent, for example pine oil, to the conditioned slurry, and then passing air through the slurry in a known manner in a froth flotation cell to effect separation of the impurities from the clay. However, many clays naturally contain a high proportion, i.e. greater than 40% by weight, of particles of extremely small dimensions, i.e. two microns equivalent spherical diameter or smaller, and these clays are therefore natural slirnes; such particles are difficult to separate by a simple froth flotation process of the type described above. The individual, extremely small particles of the clay are grouped together into large masses and are loosely bound by inter-particulate forces i.e. they are flocculated. Such masses may have impurities included and held therein and these impurities, which are bound in the larger masses, are not therefore capable of being separated by a simple froth flotation process. In fact, in many industrial froth flotation processes, all the material consisting of particles smaller than 50 microns is separated from the crude ore and discarded. In order to try to overcome this problem it has been proposed to deflocculate the clay before treating the same by a froth flotation process. To effect the deflocculation, it has been proposed to add, for example, sodium silicate to the clay slurry before the addition of the ammonium hydroxide.
It has also been proposed to add an activator to the slurry before carrying out the froth flotation process, see for example United States Patent No. 2,894,628 in which it is proposed that the froth flotation process described above should be carried out in the presence of an activator selected from ammonium, potassium and magnesium sulphates. However, all of these \known processes only work efficiently with coarse clays, i.e. clays containing not more than by weight of particles smaller than 2 microns, and do not work efficiently with clays containing a high proportion, i.e. greater than 40% by weight, of particles smaller than 2 microns equivalent spherical diameter.
SUMMARY OF Til-IE INVE'N'IIION I have now discovered that the difliculties which arise when attempting to refine by a froth flotation process clays containing more than 40% by Weight of particles smaller than 2 microns equivalent spherical diameter are, to a large extent, due tosurface contamination of the particles which reduces the effective difference between two different mineral particles. To overcome these difliculties I propose, in accordance with the present invention, to subject the particles toa thorough scrubbing prior to carrying out the froth flotation process and to carry out the froth flotation process in the presence of an activator which is a Water-soluble salt of an alkaline earth metal or a heavy metal. More particularly, according to the present invention there is provided a method of treating a clay containing at least 40% by Weight of particles smaller than 2 microns equivalent spherical diameter in order to separate therefrom titanium mineral impurities, which method comprises the steps of:
'(a) Mixing the clay in the form of an aqueous slurry having a solids content of at least 30% by weight with an alkali to raise the pH of said aqueous slurry to an alkaline value, a deflocculant, a collector for the titanium mineral impurities, and an activator consisting of a water-soluble salt of a metal chosen from the alkaline earth metals and the heavy metals;
'(b) Conditioning the clay slurry at said solids content of at least 30% by Weight for a time suflicient to dissipate therein at least 25 horsepower hours of energy per ton of solids;
(c) Adding to the conditioned clay slurry a frothing agent; and
((1) Introducing the conditioned clay slurry containing the frothing agent into a froth flotation cell and subjecting the conditioned clay slurry to a froth flotation process.
Herein the term alkaline earth metals is to be understood to include magnesium, and the term heavy metals refers to metals having a specific gravity which is greater than 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS To accomplish the thorough scrubbing of the particles before carrying out the froth flotation process, it is essential that the conditioning of the clay slurry be carried out before the frothing agent is added thereto and at a solids content of at least 30% by weight. However, it is preferred that the solids content of the aqueous clay slurry be in the range of from 40% to 60% by weight.
The activator, which is a water-soluble salt of an alkaline earth metal or a heavy metal, is advantageously a water-soluble salt of barium, calcium, cupric copper, ferrous iron, plumbous lead, magnesium, manganous manganese, strontium or zinc. Examples of suitable salts are lead acetate, lead nitrate, barium chloride and calcium chloride. The amount of activator employed is generally in the range of from 0.2 to 2.0 lbs. per ton of solids in the clay slurry.
The alkali used for raising the pH of the slurry to an alkaline value can be ammonium hydroxide although it will be appreciated that other similar materials may alternatively be used.
The deflocculant can be, for example, sodium silicate.
The collector for the titanium mineral impurities can be, for example, oleic acid, and the frothing agent can be, for example, pine oil.
After the clay slurry has been conditioned and before it is treated inthe froth flotation cell it is advantageously diluted with water to a solids content of from 15 to 20% by weight.
The whole of the necessary quantities of the activator and of the collector are not necessarily added to the aqueous slurry of the clay before the beginning of the froth flotation process. Indeed, it has been found advantageous to add about one half the required quantity of each of these reagents prior to initiating the froth flotation process; and, thereafter, during the froth flotation process, to add further, smaller quantities of collector and activator, there preferably being a period of conditioning of the aqueous slurry of the clay after each further addition of reagent.
In order that the invention may be more clearly understood and readily carried into effect, reference will now be made to the following example.
Example In this example, a sample of kaolin from Georgia, United States of America, was employed. The chosen sample contained 45% by weight of particles smaller than 2 microns equivalent spherical diameter and showed a relatively high coloration. The clay was formed into an aqueous slurry having a solids content of 40% by weight. Sodium silicate was then added to the suspension in the amount of approximately 4 lbs. of silicate per ton of clay in order to deflocculate the clay. The slurry was then partially conditioned by agitation for 6 minutes with a high-speed stirrer. After the agitation, lead acetate, as activator, was added in the amount of 1.25 pounds per ton of clay, followed by 10% ammonium hydroxide solution in the amount of 2 pounds per ton and oleic acid in the amount of 3 pounds per ton of clay. The resulting clay slurry was further conditioned for a period of 6 minutes with the high-speed stirrer. The use of the high-speed stirrer and the total conditioning time of 12 minutes at the high solids content means that there was dissipated in the clay slurry about 30 horsepower hours of energy per ton of solids. After being conditioned, the clay slurry was diluted to form a slurry having a solids content of 16%. The resulting diluted slurry was treated in a froth flotation cell after the addition of pine oil as a frothing agent. At intervals of 20 to 25 minutes, further quantities of lead acetate and oleic acid were added at from A to A2 of the original amount, each addition being followed by a conditioning period before restarting the froth flotation process. The total time of the froth flotation process was about 100 minutes.
The total consumption of reagents per ton of clay was as follows:
Lbs. Oleic acid 6.75 Ammonium hydroxide 2 Lead acetate 2.5 Sodium silicate 4 To determine the degree of purification of the clay, brightness values were measured both for the original clay and for the product of the process just described. The brightness of the clay was determined by measuring the percentage reflectance of violet light having a wave length of 458 millimicrons. The results of the tests are given in the table below. The clay treated by the process just described will for brevity be referred to as Clay A.
For comparison purposes, two separate samples of clay were processed by known methods. The first sample was formed into a slurry, conditioned for a time sufficient to dissipate therein about 10 horsepower hours of energy per ton of solids and treated with ammonium hydroxide to raise the pH level to pH 9; a froth flotation process was then carried out in known manner, using oleic acid as a collector and pine oil as a frothing agent. The clay treated by this method is referred to as Clay B in the table below. The second sample of comparison clay, Clay C, was treated in the same way as was Clay B except that sodium silicate was added before alkalination to ensure substantially complete deflocculation of the clay in the suspension.
1. A method of treating a clay to remove therefrom titanium mineral impurities, said method comprising the steps of:
(a) mixing a clay containing at least 40% by weight of particles smaller than 2 microns equivalent spherical diameter in the form of an aqueous slurry having a solids content of clay of at least 30% by weight with an alkali to raise the pH of said aqueous clay slurry to an alkaline value, a deflocculant, a collector for the titanium mineral impurities, and an activator consisting of a water-soluble salt of a metal chosen from the alkaline earth metals and the heavy metals;
(b) conditioning the aqueous clay slurry at said solids content of at least 30% by weight for a time suflicient to dissipate therein at least 25 horsepower hours of energy per ton of solids;
(0) adding to the conditioned aqueous clay slurry a frothing agent; and
(d) introducing the conditioned aqueous clay slurry containing the frothing agent into a froth flotation cell and subjecting the conditioned aqueous clay slurry to a froth flotation process.
2. A method according to claim 1, wherein the aqueous clay slurry is conditioned at a solids content of clay of from 40% to 60% by weight.
3. A method according to claim 2, wherein the conditioned aqueous clay slurry is diluted to a solids content of clay of from 15% to 20% by weight before it is subjected to a froth flotation process.
4. A method according to claim 1 wherein the heavy metal has a specific gravity greater than 4.
References Cited UNITED STATES PATENTS 1,029,579 6/ 1912 Schwerm 209-5 2,105,826 1/1938 Tartaron 209-166 2,249,569 7/1941 Phelps 209-166 2,249,570 7/ 1941 Lane 209-166 2,569,680 10/1951 Leek 209-10 2,661,842 12/1953 Duke 209-166 2,861,687 11/ 1958 Lord 209-167 2,894,628 7/ 1959 Duke 209-166 3,164,549 1/1965 Seymour 209-166 2,990,958 7/1961 Greene 209-166 3,224,582 12/1965 Iannicelli 209-166 3,337,048 8/1967 Mercade 209-5 3,353,668 11/1967 Duke 209-166 X HARRY B. THORNTON, Primary Examiner.
ROBERT HALPER, Assistant Examiner.
US. Cl. X.R. 209-166
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US1029579 *||Aug 29, 1911||Jun 11, 1912||Botho Schwerin||Method of separating substances in suspension by washing.|
|US2105826 *||Oct 18, 1935||Jan 18, 1938||Phosphate Recovery Corp||Concentration of nonmetallic minerals|
|US2249569 *||Jul 29, 1940||Jul 15, 1941||Edgar Brothers Company||Treatment of clay by flotation|
|US2249570 *||Jul 29, 1940||Jul 15, 1941||Edgar Brothers Company||Fractionation of clay|
|US2569680 *||Feb 4, 1949||Oct 2, 1951||Edgar Brothers Company||Flotation process for whitening clay|
|US2661842 *||Aug 3, 1950||Dec 8, 1953||Attapulgus Minerals & Chemical||Concentration of phosphate ores|
|US2861687 *||Sep 9, 1955||Nov 25, 1958||Southwestern Eng Co||Flotation of heavy metal oxides|
|US2894628 *||Jul 13, 1956||Jul 14, 1959||Minerals & Chemicals Corp Of A||Clay brightness by flotation|
|US2990958 *||Dec 9, 1958||Jul 4, 1961||Minerals & Chem Philipp Corp||Froth flotation method|
|US3164549 *||Jul 31, 1961||Jan 5, 1965||Armour & Co||Flotation separation of phosphate ores|
|US3224582 *||Jun 1, 1965||Dec 21, 1965||Huber Corp J M||Kaolin clay beneficiation|
|US3337048 *||Dec 2, 1964||Aug 22, 1967||Minerals & Chem Philipp Corp||Method for beneficiating clay by flotation|
|US3353668 *||Dec 16, 1963||Nov 21, 1967||Mineral & Chemicals Philipp Co||Method for improving the brightness of clay|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3770213 *||Jan 18, 1972||Nov 6, 1973||Bethlehem Steel Corp||Process for separating carbon from iron-bearing fines in blast furnace flue dusts|
|US3915391 *||Aug 29, 1974||Oct 28, 1975||Engelhard Min & Chem||Recovery of scheelite from ores by flotation|
|US3919079 *||Mar 7, 1973||Nov 11, 1975||Weston David||Flotation of sulphide minerals from sulphide bearing ore|
|US3964997 *||Sep 26, 1974||Jun 22, 1976||David Weston||Concentration of gold, sulphide minerals and uranium oxide minerals by flotation from ores and metallurgical plant products|
|US3974067 *||Oct 8, 1974||Aug 10, 1976||Anglo-American Clays Corporation||Method for improving clay brightness utilizing magnetic separation|
|US3979282 *||Jan 16, 1975||Sep 7, 1976||English Clays Lovering Pochin & Company Limited||Flotation of fine-grained materials|
|US4014709 *||Jun 8, 1976||Mar 29, 1977||Engelhard Minerals & Chemicals Corporation||Opacifying pigments and methods for making same|
|US4097372 *||Jul 8, 1976||Jun 27, 1978||Anglo-American Clays Corporation||Method for improving clay brightness utilizing magnetic separation|
|US4098688 *||Jul 21, 1976||Jul 4, 1978||Anglo-American Clays Corporation||Brightening of clay by froth flotation|
|US4492628 *||Aug 25, 1982||Jan 8, 1985||Freeport Kaolin Company||Method of treating clay to improve its whiteness|
|US4501658 *||Aug 25, 1982||Feb 26, 1985||Freeport Kaolin Company||Method of conditioning clay for flotation using in situ ferrous activator|
|US4514288 *||Oct 13, 1983||Apr 30, 1985||Mobil Oil Corporation||Ore beneficiation process|
|US4629556 *||Nov 29, 1984||Dec 16, 1986||Thiele Kaolin Company||Purification of kaolin clay by froth flotation using hydroxamate collectors|
|US4997550 *||Nov 13, 1989||Mar 5, 1991||Ecc America Inc.||Method for improved flotation of discoloring impurities from kaolinite|
|US5037534 *||Sep 14, 1989||Aug 6, 1991||J. M. Huber Corporation||Flotation aid and process for removal of impurities from silicate minerals|
|US5137574 *||Nov 30, 1990||Aug 11, 1992||Ecc America Inc.||Method for producing high opacifying kaolin pigment|
|US5180511 *||Jun 20, 1991||Jan 19, 1993||J.M. Huber Corporation||Flotation aid and process for removal of impurities from silicate minerals|
|US5213687 *||Jan 22, 1992||May 25, 1993||Ecc International Inc.||Apparatus for filtering mineral slurries|
|US5223155 *||Jan 22, 1992||Jun 29, 1993||Ecc International Inc.||Method for filtering mineral slurries|
|US5332493 *||Apr 28, 1992||Jul 26, 1994||Ecc International Inc.||Method for improving rheological properties of kaolin clays|
|US5371051 *||Dec 23, 1993||Dec 6, 1994||Ecc International Inc.||Method for producing high opacifying kaolin pigment|
|US5454865 *||Dec 23, 1993||Oct 3, 1995||Ecc International Inc.||Method for preparing refined kaolin in clay products|
|US5522924 *||Mar 17, 1995||Jun 4, 1996||Ecc International Inc.||Method for producing high brightness low abrasion calcined kaolin pigment|
|US5522986 *||Mar 3, 1995||Jun 4, 1996||Thiele Kaolin Company||Process for removing impurities from kaolin clays|
|US5545338 *||Jan 19, 1993||Aug 13, 1996||Ecc International Inc.||Method for filtering mineral slurries|
|US5547574 *||Jan 19, 1993||Aug 20, 1996||Ecc International Inc.||Apparatus for filtering mineral slurries|
|US5685899 *||Jul 28, 1995||Nov 11, 1997||Thiele Kaolin Company||Process for conditioning kaolin clays prior to removing impurities|
|US5810998 *||Jun 5, 1997||Sep 22, 1998||Thiele Kaolin Company||Process for improving the brightness of fine-grained kaolin clays|
|US5891326 *||Dec 8, 1997||Apr 6, 1999||Thiele Kaolin Company||Process for removing impurities from kaolin clays|
|US6007618 *||Nov 10, 1997||Dec 28, 1999||Thiele Kaolin Company||Kaolin clays which are conditioned prior to removing impurities|
|US6186335||Mar 20, 1998||Feb 13, 2001||Thiele Kaolin Company||Process for beneficiating kaolin clays|
|US6200377||Apr 16, 1999||Mar 13, 2001||Thiele Kaolin Company||Process for beneficiation of mixtures of mineral particles|
|US6390301||Jul 18, 2000||May 21, 2002||Cytec Industries Inc.||Process for removing impurities from kaolin clays|
|US7393462||May 13, 2004||Jul 1, 2008||Cytec Technology Corp.||Process and reagent for separating finely divided titaniferrous impurities from Kaolin|
|US7648032||Mar 22, 2005||Jan 19, 2010||Imerys Pigments, Inc.||Effective reductive bleaching of mineral slurries|
|US7727324||Apr 28, 2005||Jun 1, 2010||Imerys Pigments, Inc.||Compositions comprising kaolin having nanosize dimensions|
|US7780779||Feb 8, 2006||Aug 24, 2010||Imerys Pigments, Inc.||Method for separating mixture of finely divided minerals|
|US7806978||Dec 15, 2003||Oct 5, 2010||Imerys Pigments, Inc.||Fine platy kaolin composition|
|US8016936||May 2, 2005||Sep 13, 2011||Imerys Pigments, Inc.||Methods of calcining particulate material|
|US8083848||Feb 8, 2006||Dec 27, 2011||Imerys Pigments, Inc.||Compositions comprising fine sedimentary kaolin and methods for preparing same|
|US8465583||Dec 21, 2011||Jun 18, 2013||Imerys Pigments, Inc.||Compositions comprising fine sedimentary kaolin and methods for preparing same|
|US20050252834 *||May 13, 2004||Nov 17, 2005||Abdul Gorken||Process and reagent for separating finely divided titaniferrous impurities from Kaolin|
|US20060124033 *||Dec 15, 2003||Jun 15, 2006||Imerys Pigments, Inc.||Fine platy kaolin composition|
|US20060176603 *||Feb 7, 2006||Aug 10, 2006||Hiroshi Itagaki||Device, method, and program product for controlling a tape data storage drive|
|US20060185557 *||Feb 8, 2006||Aug 24, 2006||Garska Michael J||Method for separating mixture of finely divided minerals|
|US20060186024 *||Jan 30, 2006||Aug 24, 2006||Criscuolo Paulo S R||Method for processing fine kaolin|
|US20060249051 *||Feb 8, 2006||Nov 9, 2006||Pruett Robert J||Compositions comprising fine sedimentary kaolin and methods for preparing same|
|US20070194276 *||Mar 22, 2005||Aug 23, 2007||Jun Yuan||Effective reductive bleaching of mineral slurries|
|US20070221092 *||Apr 28, 2005||Sep 27, 2007||Brown H Vincent||Compositions Comprising Kaolin Having Nanosize Dimensions|
|US20080105166 *||May 2, 2005||May 8, 2008||Imerys Pigments, Inc.||Methods of Calcining Particulate Material|
|US20080182743 *||May 1, 2006||Jul 31, 2008||Imerys Pigments, Inc.||Methods of Heat-Treating Particulate Material|
|US20090169890 *||Dec 18, 2006||Jul 2, 2009||Pruett Robert J||High Brightness and Low Abrasion Calcined Kaolin|
|CN102060303A *||Dec 3, 2010||May 18, 2011||孝义市天章铝业有限公司||Method for preparing artificial mullite raw material by bauxite|
|EP0104099A2 *||Aug 5, 1983||Mar 28, 1984||Engelhard Corporation||Method for froth flotation|
|EP0104099A3 *||Aug 5, 1983||Jan 2, 1986||Engelhard Corporation||Apparatus and method for froth flotation|
|EP0104100A2 *||Aug 5, 1983||Mar 28, 1984||Engelhard Corporation||Method of treating clay in order to remove mineral titanium-based impurities|
|EP0104100A3 *||Aug 5, 1983||Jan 2, 1986||Engelhard Corporation||Method of treating clay in order to remove mineral titanium-based impurities|
|EP1686104A1||Jan 31, 2006||Aug 2, 2006||Companhia Vale Do Rio Doce||A method for processing fine kaolin|
|WO1992009662A1 *||Nov 26, 1991||Jun 11, 1992||Ecc International Inc.||Method for producing high opacifying kaolin pigment|
|WO1996027444A1 *||Mar 1, 1996||Sep 12, 1996||Thiele Kaolin Company||Process for removing impurities from kaolin clays|
|WO2004085336A2||Mar 16, 2004||Oct 7, 2004||Imerys Kaolin, Inc.||Unusually narrow particle size distribution calcined kaolins|
|WO2005113687A1||Apr 27, 2005||Dec 1, 2005||Cytec Technology Corp.||Process and reagent for separating finely divided titaniferrous impurities from kaolin|
|U.S. Classification||209/5, 209/166, 209/901|
|International Classification||B03D1/06, B03D1/001, C04B33/10|
|Cooperative Classification||B03D1/06, Y10S209/901, C04B33/06, C04B33/30, C04B33/10, B03D1/001|
|European Classification||C04B33/30, C04B33/10, C04B33/06, B03D1/001, B03D1/06|