Method for preparing a composition comprising coloured silicate mineral particles and a composition comprising coloured silicate mineral particles

Abstract

A method for preparing a composition including silicate mineral particles that have coloring properties in which a talcose composition, including phyllosilicate mineral particles chosen from the group formed: from the particles having the chemical formula: ((Si.sub.xGe.sub.1-x).sub.4 M.sub.3O.sub.10 (OH).sub.2, the particles having at least one interlayer space and having the chemical formula: (Si.sub.xGe.sub.1-x).sub.4 M.sub.3- O.sub.10 (OH).sub.2, (M.sup.m+).sub..nH.sub.2O: -M having the formula Mg.sub.y(1)Co.sub.y(2)Zn.sub.y(3)Cu.sub.y(4)Mn.sub.y(5) Fe.sub.y(6)Ni.sub.y(7)Cry(8); -M.sup.m+ designating at least one interlayer cation, the silicate mineral particles having a thickness of less than 100 nm and of which the largest dimension is less than 10 .Math., is brought into contact with a dye solution, including dye cations, of at least one element chosen from the transition metals, the lanthanides and the actinides. The composition obtained by this method is also described.

Claims

1. A method for preparing a composition comprising silicate mineral particles which have coloring properties, wherein: a talcose composition, comprising phyllosilicate mineral particles is selected from the group consisting of: particles formed of a stack of elementary lamellae and having the chemical formula:
(Si.sub.xGe.sub.1-x).sub.4M.sub.3O.sub.10(OH).sub.2 M denoting at least one divalent metal and having the formula Mg.sub.y(1)Co.sub.y(2)Zn.sub.y(3)Cu.sub.y(4)Mn.sub.y(5)Fe.sub.y(6)Ni.sub.y(7)Cr.sub.y(8); each y(i) representing a real number of the interval [0; 1], and such that $\underset{i=1}{\overset{8}{.Math.}}y\left(i\right)=1,$ x being a real number of the interval [0; 1], and particles formed of a stack of elementary lamellae and having at least one interfoliar space between two consecutive elementary lamellae and having the chemical formula:
(Si.sub.xGe.sub.1-x).sub.4M.sub.3- O.sub.10(OH).sub.2,(W.sup.M+).sub..nH.sub.2O M denoting at least one divalent metal and having the formula Mg.sub.y(1)Co.sub.y(2)Zn.sub.y(3)Cu.sub.y(4)Mn.sub.y(5)Fe.sub.y(6)Ni.sub.y(7)Cr.sub.y(8); each y(i) representing a real number of the interval [0; 1], and such that $\underset{i=1}{\overset{8}{.Math.}}y\left(i\right)=1,$ M.sup.m+denoting at least one cation, named an interfoliar cation, present in at least one interfoliar space of said elementary lamellae, x being a real number of the interval [0; 1], being a real number of the interval [0; 3[ and denoting a cation deficit of said elementary lamellae, being a real number of the interval [0; 3[ and denoting a proportion of interfoliar cation(s) M.sup.m+ present in the interfoliar space(s) of said elementary lamellae, m being a real number of the interval [1; 3] and denoting a cation charge of the cation M.sup.m+, n referring to a number of molecule(s) of water associated with said particles, said silicate mineral particles having a thickness of less than 100 nm and the largest dimension of which is less than 10 m, bringing said talcose composition into contact with a solution, named a coloring solution, comprising cations, named coloring cations, of at least one element chosen from the transition metals, the lanthanides and the actinides, in order to obtain a talcose composition comprising colored silicate mineral particles.

2. The method as claimed in claim 1, wherein said particles have a thickness of from 1 nm to 100 nm, and the largest dimension of which is from 20 nm to 10 m.

3. The method as claimed in claim 1, wherein said coloring solution is an aqueous solution.

4. The method as claimed in claim 1, wherein said coloring solution is a solution comprising at least one metal salt selected from the group consisting of the chromium salts, manganese salts, iron salts, cobalt salts, nickel salts, copper salts, zinc salts, cerium salts, neodymium salts, gadolinium salts, holmium salts, and mixtures thereof.

5. The method as claimed in claim 1, wherein said talcose composition is contacted with said coloring solution for a duration of from 10 minutes to 24 hours.

6. The method as claimed in claim 1, wherein said talcose composition is contacted with said coloring solution at a temperature of from 5 C. to 100 C.

7. The method as claimed in claim 1, wherein the colored silicate mineral particles that are obtained are rinsed with an aqueous solution which is at least substantially free of coloring cation.

8. The method as claimed in claim 1, wherein the colored silicate mineral particles that are obtained are dried.

9. The method as claimed in claim 1, wherein the talcose composition comprising colored phyllosilicate mineral particles that have been obtained is dried at a temperature of from 60 C. to 200 C.

10. The method as claimed in claim 1, wherein said composition comprising colored phyllosilicate mineral particles that has been obtained is subjected to heat treatment at a temperature of from 200 C. to 600 C.

11. The method as claimed in claim 1, wherein said phyllosilicate mineral particles are prepared by hydrothermal treatment of a composition comprising particles of the formula (Si.sub.xGe.sub.1-x).sub.4 M.sub.3 O.sub.11, nH.sub.2O.

12. The method as claimed in claim 11, wherein said hydrothermal treatment is carried out for a duration of from 30 minutes to 60 days and at a temperature of from 150 C. to 600 C.

13. The method as claimed in claim 11, wherein said hydrothermal treatment is carried out under saturation vapor pressure.

14. The method as claimed in claim 2, wherein said coloring solution is an aqueous solution.

15. The method as claimed in claim 12, wherein said hydrothermal treatment is carried out under saturation vapor pressure.

16. The method as claimed in claim 2, wherein said thickness of said particles is from 5 nm to 50 nm.

17. The method as claimed in claim 5, wherein said duration that said talcose composition is contacted with said coloring solution is from 1 hour to 2 hours.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The sole FIGURE shows diffractograms corresponding to the X-ray diffraction analysis carried out on nine colored compositions obtained by a method according to the invention, starting from talcose compositions comprising phyllosilicate mineral particles, with different coloring cations.

DETAILED DESCRIPTION OF THE INVENTION

(2) Other objects, advantages and feature of the invention will become apparent upon reading the description and examples which follow and which refer to the single feature.

(3) A talcose composition used in a method according to the invention can be prepared, for example, by the following synthesis protocol.

(4) A/General Protocol for the Synthesis of a Talcose Composition Used in a Method According to the Invention

(5) 1/Preparation of a Gel Containing Silicon and/or Germanium and Metal

(6) According to a first variant, the gel containing silicon and/or germanium and metal is prepared by a coprecipitation according to the following reaction equation:

(7) $4\left(\begin{array}{c}{\left({\mathrm{Na}}_2{\mathrm{OSiO}}_2\right)}_x\\ {\left({\mathrm{Na}}_2{\mathrm{OGeO}}_2\right)}_{1-x}\end{array}\right)+2\mathrm{HCl}+{mH}_{2}O+3\left(\begin{array}{c}{y}_{\left(1\right)}\left({\mathrm{MgCl}}_2\right)+y_{\left(2\right)}\left({\mathrm{CoCl}}_2\right)+y_{\left(3\right)}\left({\mathrm{ZnCl}}_2\right)+\\ y_{\left(4\right)}\left({\mathrm{CuCl}}_2\right)+y_{\left(5\right)}\left({\mathrm{MnCl}}_2\right)+y_{\left(6\right)}\left({\mathrm{FeCl}}_2\right)+\\ y_{\left(7\right)}\left({\mathrm{NiCl}}_2\right)+y_{\left(8\right)}\left({\mathrm{CrCl}}_2\right)\end{array}\right).Math.{\left[{\mathrm{Si}}_x{\mathrm{Ge}}_{1-x}\right)}_4{M}_3{O}_{11}.Math.n^{}{H}_{2}O]+8\mathrm{NaCl}+\left(m-n^{}+1\right)H_{2}O$

(8) This coprecipitation reaction allows a hydrated gel containing silicon and/or germanium and metal and having the stoichiometry of talc (4 atoms of silicon (Si) and/or germanium (Ge) for 3 atoms of said divalent metal M) to be obtained.

(9) It is carried out starting from: 1. an aqueous solution of penta-hydrated sodium metasilicate or an aqueous solution of sodium metagermanate, or a mixture of these two solutions in the molar proportions x/(1x), 2. a metal chloride solution prepared with one or more metal salt(s) (in the form of hygroscopic crystals) diluted in distilled water, and 3. a 1N hydrochloric acid solution.

(10) The gel containing silicon and/or germanium and metal is prepared according to the following protocol: 1. the hydrochloric acid solution and the metal chloride(s) solution are mixed, 2. this mixture is added to the sodium metasilicate and/or sodium metagermanate solution; the coprecipitation gel forms instantly, 3. the gel is recovered after centrifugation (at 7000 revolutions/minute for 15 minutes) and removal of the supernatant (sodium chloride solution that has formed), 4. the gel is washed with distilled or osmozed water or with tap water (at least two washing/centrifugation cycles are necessary).

(11) According to a second variant, the gel containing silicon and/or germanium and metal can be prepared by a coprecipitation reaction involving, as reagent, at least one compound comprising silicon, at least one dicarboxylate salt of the formula M(R.sub.1COO).sub.2 (R.sub.1 being chosen from H and alkyl groups having fewer than 5 carbon atoms) in the presence of at least one carboxylate salt of the formula R.sub.2COOX wherein X denotes a metal chosen from the group formed of Na and K, and R.sub.2 is chosen from H and alkyl groups having fewer than 5 carbon atoms.

(12) This coprecipitation reaction allows a hydrated hydrogel containing silicon and/or germanium and metal and having the stoichiometry of talc (4 Si/Ge for 3 M, M having the formula Mg.sub.y(1)Co.sub.y(2)Zn.sub.y(3)Cu.sub.y(4)Mn.sub.y(5)Fe.sub.y(6)Ni.sub.y(7)Cr.sub.y(8); each y(i) representing a real number of the interval [0; 1], and such that

(13) $\underset{i=1}{\overset{8}{.Math.}}y\left(i\right)=1)$
to be obtained.

(14) The hydrogel containing silicon and/or germanium and metal is prepared by a coprecipitation reaction carried out starting from: 1. an aqueous solution of penta-hydrated sodium metasilicate or an aqueous solution of sodium metagermanate, or a mixture of these two solutions in the molar proportions x/(1x), 2. a solution of dicarboxylate salt(s) prepared with one or more dicarboxylate salt(s) of the formula M(R.sub.1COO).sub.2 diluted in a carboxylic acid, such as acetic acid, and 3. a solution of carboxylate salt(s) prepared with one or more carboxylate salt(s) of the formula R.sub.2COOX diluted in distilled water.

(15) The hydrogel containing silicon and/or germanium and metal is prepared according to the following protocol: 1. the sodium metasilicate solution and the solution of carboxylate salt(s) of formula R.sub.2COOX are mixed, 2. the solution of dicarboxylate salt(s) of the formula M(R.sub.1COO).sub.2 is added quickly thereto; the coprecipitation hydrogel forms instantly.

(16) At the end of this first phase, a hydrated gel containing silicon and/or germanium and metal (Si.sub.xGe.sub.1-x).sub.4M.sub.3O.sub.11, nH.sub.2O of gelatinous consistency is obtained (optionally in the presence of the carboxylate salt(s) of the formulae R.sub.2COOX and R.sub.1COOX in the case of the second variant). The gel has thixotropic behavior, that is to say it passes from a viscous state to a liquid state when it is stirred and then returns to its original state if it is allowed to rest for a sufficient time.

(17) The gel containing silicon and/or germanium and metal can also be recovered after centrifugation (for example from 3000 to 15,000 revolutions per minute for from 5 to 60 minutes) and removal of the supernatant, optionally washing with demineralized water (for example two successive washings and centrifugations) and then drying, for example in an oven (60 C., 2 days), by lyophilization, by spray drying or by drying under microwave irradiation. The particles containing silicon and/or germanium and metal of the formula (Si.sub.xGe.sub.1-x).sub.4M.sub.3O.sub.11, nH.sub.2O can thus be stored in the form of a powder with a view to a subsequent hydrothermal treatment. The particles containing silicon and/or germanium and metal that are obtained are, if necessary, ground by means of a mortar (for example an agate mortar) in order to obtain a homogeneous powder.

(18) 2/Hydrothermal Treatment of the Gel Containing Silicon and/or Germanium and Metal

(19) The gel containing silicon and/or germanium and metal as obtained hereinbefore is subjected to a hydrothermal treatment at a temperature of from 150 C. to 600 C., and especially at a temperature of from 150 C. to 400 C.

(20) In order to carry out the hydrothermal treatment: 1. the gel is placed in a reactor (of 400 ml); the water/solid ratio is optionally adjusted by adding water, especially in order to avoid calcination of the solid fraction); in order to avoid any problem of leakage from the reactor, the reactor is filled to of its volume, 2. there is optionally added, with stirring, a solution comprising at least one carboxylate salt of the formula R.sub.2COOX, in hydrated or anhydrous form, X denoting a metal chosen from the group formed of Na and K, and R.sub.2 being chosen from H and alkyl groups having fewer than 5 carbon atoms, 3. the reactor is placed inside an oven or conduction oven at the reaction temperature (established at from 150 C. to 600 C., in particular from 150 C. to 400 C.) throughout the treatment (from 30 minutes to 60 days).

(21) At the end of this hydrothermal treatment, a colloidal talcose composition comprising phyllosilicate mineral particles, in solution in water, is obtained. The mineral particles obtained at the end of this hydrothermal treatment can in particular be T.O.T.-swelling T.O.T. interlayer particles.

(22) The carboxylate salt optionally present during the hydrothermal treatment can be added at the time said hydrothermal treatment is carried out and/or can be obtained from the precipitation medium of the gel containing silicon and/or germanium and metal according to the second variant for the preparation of the gel containing silicon and/or germanium and metal. Carrying out the hydrothermal treatment in the presence of a carboxylate salt allows the reaction of converting the gel containing silicon and/or germanium and metal into a talcose composition comprising phyllosilicate mineral particles to be improved, especially by accelerating it. In the case where the hydrothermal treatment is carried out in the presence of such a carboxylate salt, the temperature inside the oven or autoclave is from 150 C. to 400 C.

(23) At the end of this hydrothermal treatment, the contents of the reactor are recovered after filtration and/or optionally centrifugation (for example at from 3000 to 15,000 revolutions per minute for from 5 to 60 minutes) and removal of the supernatant. The recovered talcose composition is optionally dried, for example in an oven (60 C., 2 days), by lyophilization, by spray drying or by drying under microwave irradiation.

(24) At the end of such a hydrothermal treatment there is obtained a divided solid composition comprising, for example, T.O.T.-swelling T.O.T. interlayer particles having the formula:
Si.sub.4Mg.sub.3O.sub.10(OH).sub.2/Si.sub.4Mg.sub.3-O.sub.10(OH).sub.2,(Mg.sup.2+).nH.sub.2O,
Si.sub.4Ni.sub.3O.sub.10(OH).sub.2/Si.sub.4Ni.sub.3-O.sub.10(OH).sub.2,(Ni.sup.2+).nH.sub.2O,
Si.sub.4Co.sub.3O.sub.10(OH).sub.2/Si.sub.4Co.sub.3-O.sub.10(OH).sub.2,(Co.sup.2+).nH.sub.2O,
Si.sub.4Cu.sub.3O.sub.10(OH).sub.2/Si.sub.4Cu.sub.3-O.sub.10(OH).sub.2,(Cu.sup.2+).nH.sub.2O,
Si.sub.4Mn.sub.3O.sub.10(OH).sub.2/Si.sub.4Mn.sub.3-O.sub.10(OH).sub.2,(Mn.sup.2+).nH.sub.2O,
Si.sub.4Fe.sub.3O.sub.10(OH).sub.2/Si.sub.4Fe.sub.3-O.sub.10(OH).sub.2,(Fe.sup.2+).nH.sub.2O, or
Si.sub.4Zn.sub.3O.sub.10(OH).sub.2/Si.sub.4Zn.sub.3-O.sub.10(OH).sub.2,(Zn.sup.2+).nH.sub.2O,
according to the nature of the metal chloride(s) used for the preparation of the gel containing silicon and/or germanium and metal (and also, where appropriate, the respective proportions of those metal chlorides).
B/Method for Preparing a Talcose Composition Comprising Colored Phyllosilicate Mineral Particles According to the Invention

(25) The phyllosilicate mineral particles, for example T.O.T.-swelling T.O.T. interlayer particles as obtained hereinbefore, are contacted with a solution, named a coloring solution, comprising at least one coloring cation of an element chosen from the transition metals, the lanthanides and the actinides.

(26) To that end: 1. the previously dried (for example in an oven) phyllosilicate mineral particles are placed in an aqueous solution in which there is dissolved a coloring salt, as defined hereinbefore, for a predetermined duration of from 5 minutes to 7 days, with or without stirring, the concentration of the salt in the solution being predetermined and being from 0.2 mol/L to 5 mol/L, 2. the phyllosilicate mineral particles are recovered by centrifugation of the solution, for example for 10 minutes at 3500 revolutions/minute, and removal of the supernatant solution, 3. optionally, the phyllosilicate mineral particles are rinsed one to two times with distilled water, by centrifugation, for example for 10 minutes at 3500 revolutions/minute, and removal of the supernatant solution each time, in order to remove excess coloring cations, and 4. the phyllosilicate mineral particles that are obtained are dried, for example for 12 hours in an oven at 100 C.

Examples 1 to 11

(27) 10 samples of T.O.T.-swelling T.O.T. interlayer particles Si.sub.4M.sub.3O.sub.10(OH).sub.2/(Si.sub.xGe.sub.1-x).sub.4M.sub.3-O.sub.10 (OH).sub.2, (M.sup.m+).sub..nH.sub.2O are thus prepared: starting from T.O.T.-swelling T.O.T. interlayer particles Si.sub.4Mg.sub.3O.sub.10(OH).sub.2/Si.sub.4Mg.sub.3-O.sub.10(OH).sub.2, (Mg.sup.2+).nH.sub.2O and using as the coloring salt CrCl.sub.3, MnCl.sub.2, FeCl.sub.3, CoCl.sub.2, NiCl.sub.2, CuCl, CeCl.sub.3, NdCl.sub.3 and HoCl.sub.3 (samples 1 to 9) and starting from T.O.T.-swelling T.O.T. interlayer particles Si.sub.4Ni.sub.3O.sub.10(OH).sub.2/Si.sub.4Ni.sub.3-O.sub.10(OH).sub.2, (Ni.sup.2+).nH.sub.2O and using FeCl.sub.3 as the coloring salt (sample 10).

(28) There is used 1 gram of the T.O.T.-swelling T.O.T. interlayer particles Si.sub.4Mg.sub.3O.sub.10(OH).sub.2/Si.sub.4Mg.sub.3-O.sub.10(OH).sub.2, (Mg.sup.2+).nH.sub.2O or Si.sub.4Ni.sub.3O.sub.10(OH).sub.2/Si.sub.4Ni.sub.3-O.sub.10(OH).sub.2, (Ni.sup.2+).nH.sub.2O previously dried in an oven in 40 ml of an aqueous solution in which a coloring salt is dissolved in a concentration of 1 mol/L, for one hour, with stirring.

(29) Sample 11 corresponds to a T.O.T.-swelling T.O.T interlayer Si.sub.4Mg.sub.3O.sub.10(OH).sub.2/Si.sub.4Mg.sub.3-O.sub.10(OH).sub.2, (Mg.sup.2+).nH.sub.2O which has not been subjected to a coloring step according to the invention.

(30) The 11 samples were prepared according to the first variant for the preparation of the gel containing silicon and/or germanium and metal, followed by a hydrothermal treatment for 48 hours at 160 C.

(31) The mineral T.O.T.-swelling T.O.T. interlayer particles of samples 1 to 11 have a thickness of less than 10 nm and a largest dimension of less than 50 nm. In particular, they have, for the majority, a thickness of less than 5 nm and a largest dimension of less than 30 nm. The thickness and the largest dimension of said particles were measured by observation with a transmission electron microscope (TEM).

(32) In Table 1 there are recorded, for each of samples 1 to 10 of T.O.T.-swelling T.O.T. interlayer particles, the nature of the element M, the nature of the coloring cation Z, the concentration by mass [Z] of coloring cation Z.sup.P+ in said T.O.T.-swelling T.O.T. interlayer particles measured by means of a Cameca SX50 electron microprobe, the atomic ratio of coloring cation Z to silicon atoms (Z/Si), and the color obtained.

(33) TABLE-US-00001 TABLE 1 [Z] Atomic ratio M Z (wt. %) Z/Si Color Sample no. Mg Cr 2.1 0.036 grey-green 1 Mg Mn 3.3 0.061 brown 2 Mg Fe 4.1 0.070 ochre 3 Mg Co 4.0 0.072 pink 4 Mg Ni 4.6 0.076 light green 5 Mg Cu 5.2 0.085 blue 6 Mg Ce 7.1 0.060 yellow 7 Mg Nd 6.6 0.054 very light pink 8 Mg Ho 7.3 0.058 very light pink 9 Ni Fe 2.2 0.047 green 10 Mg white 11

Examples 12 to 21

(34) Samples 12 to 21 were prepared according to the first variant for the preparation of the gel containing silicon and/or germanium and metal, followed by a hydrothermal treatment at 300 C. for 3 days (72 hours) for samples 12 to 14 and at 300 C. for 6 hours for samples 15 to 21.

(35) There is used 0.5 gram of phyllosilicate mineral particles previously dried in an oven in 40 ml of an aqueous solution in which a coloring salt is dissolved in a molar concentration [Z].sub.2, for a duration t.sub.2, with stirring.

(36) The coloring step for samples 12 to 21 is carried out in accordance with steps 1 to 3 described above, and the colored phyllosilicate mineral particles obtained are then dried in an oven at 110 C., for 12 hours for samples 12 to 15 and for 36 hours for samples 16 to 21.

(37) Furthermore, during the coloring step, samples 12 to 15 were subjected to ultrasound for the last 20 minutes of this step. Sample 15 was also subjected to ultrasound for one hour at the start of the coloring step. In addition, sample 17 was subjected to ultrasound for 3 minutes at the start of the coloring step and five times for 3 minutes during the coloring step.

(38) The phyllosilicate mineral particles of samples 12 to 21 have a thickness of less than 50 nm and a largest dimension of less than 200 nm. The thickness and the largest dimension of said particles were measured by observation with a transmission electron microscope (TEM).

(39) In Table 2 there are recorded, for each of samples 12 to 21, the nature of the element M of the phyllosilicate mineral particles, the nature of the coloring cation Z, the molar concentration [Z].sub.2 of coloring cation Z.sup.P+ in the coloring solution, the duration t.sub.2 of the coloring step, and the color obtained.

(40) TABLE-US-00002 TABLE 2 [Z].sub.2 M Z (mol .Math. L.sup.1) t.sub.2 Color Sample no. Mg Ni 3 6 days light green 12 Ni Ni 3 6 days light green 13 Co Ni 3 6 days pink 14 Mg Ni 3 7 days very light green 15 Mg Ni 3 4 days light green 16 Mg Ni 3 4 days light green 17 Mg Ni 1 4 days light green 18 Mg Mn 1 4 days brown 19 Mg Co 1 4 days beige 20 Mg Fe 1 4 days ochre 21

Examples 22 to 25

(41) Samples 22 to 25 were prepared according to the first variant of the preparation of the gel containing silicon and/or germanium and metal, followed by a hydrothermal treatment at a temperature T.sub.3 for a duration t.sub.3.

(42) The coloring step for samples 22 to 25 is carried out in accordance with steps 1 to 3 described above. There is used 0.6 gram of phyllosilicate mineral particles for sample 22 (starting from a gel having a solids content of 10%) and 1 gram of phyllosilicate mineral particles previously dried in an oven for samples 23 to 25, in 40 ml of an aqueous solution in which a coloring salt is dissolved in a molar concentration of 1 mol/L, for 30 minutes, with stirring. The recovered particles were then dried in an oven at 110 C. for 48 hours.

(43) Furthermore, during the coloring step, samples 22, 23 and 24 were at the same time subjected to ultrasound. The temperature at which the coloring step is carried out for samples 22, 23 and 24 is 20 C. Sample 25 was not subjected to ultrasound during the coloring step. The temperature at which the coloring step is carried out for sample 25 is 80 C.

(44) The phyllosilicate mineral particles of samples 22 to 25 have a thickness of less than 50 nm and a largest dimension of less than 200 nm. The thickness and the largest dimension of said particles were measured by observation with a transmission electron microscope (TEM).

(45) In Table 3 there are recorded, for each of samples 22 to 25 of phyllosilicate mineral particles, the nature of the element M, the nature of the coloring cation Z, the temperature T.sub.3 and the duration t.sub.3 of the hydrothermal treatment by which the phyllosilicate mineral particles were prepared, and the color obtained after the coloring step.

(46) TABLE-US-00003 TABLE 3 T3 M Z ( C.) t.sub.3 Color Sample no. Mg Ni 300 6 hours light green 22 Mg Ni 220 2 days light green 23 Mg Ni 160 2 days light green 24 Mg Ni 160 2 days green 25

Examples 26 to 29

(47) Samples 26 to 29 were prepared according to the first variant of the preparation of the gel containing silicon and/or germanium and metal, followed by a hydrothermal treatment at 160 C. for 3 days (72 hours) for samples 26, 27 and 29 and at 160 C. for 2 days (48 hours) for sample 28.

(48) There is used 1 gram of phyllosilicate mineral particles for samples 26 and 27 and 2 grams of phyllosilicate mineral particles for samples 28 and 29. The phyllosilicate mineral particles previously dried in an oven are contacted with 40 ml of an aqueous solution in which a coloring salt is dissolved in a molar concentration [Z].sub.2, for a duration t.sub.2, with stirring.

(49) The coloring step for samples 26 to 29 is carried out in accordance with steps 1 to 3 described above, and the colored phyllosilicate mineral particles obtained are then dried in an oven at 110 C. for 12 hours for samples 26 and 27 and at 110 C. for 24 hours for samples 28 and 29.

(50) Furthermore, at the start of the coloring step, samples 28 and 29 were subjected to ultrasound for 2 minutes.

(51) The phyllosilicate mineral particles of samples 26 to 29 have a thickness of less than 50 nm and a largest dimension of less than 200 nm. The thickness and the largest dimension of said particles were measured by observation with a transmission electron microscope (TEM).

(52) In Table 4 there are recorded, for each of samples 26 to 29, the nature of the element M of the phyllosilicate mineral particles, the nature of the coloring cation Z, the molar concentration [Z].sub.2 of coloring cation Z.sup.P+ in the coloring solution, the duration t.sub.2 of the coloring step, and the color obtained.

(53) TABLE-US-00004 TABLE 4 [Z].sub.2 M Z (mol .Math. L.sup.1) t.sub.2 Color Sample no. Ni Fe 1 60 minutes green 26 Ni Ni 1 2 hours green 27 Mg Co 1 2 hours pink to violet 28 Ni Co 1 2 hours green 29

(54) Such compositions comprising colored phyllosilicate mineral particles are of particular interest, for example, in the cosmetics field. It is possible, for example, to envisage using these particles in cosmetic compositions for care and/or make-up, as mineral fillers and/or as a coloring agent. Such compositions of colored phyllosilicate mineral particles will further allow organic pigments to be reduced or replaced.

Comparative Example

(55) By way of comparative example, particles of a pure natural talc obtained from the Trimouns quarry (Luzenac, France) having a thickness of greater than 300 nm and the largest dimension of which is greater than 20 m were contacted with coloring cations in a coloring step according to the invention.

(56) Said natural talc particles (1 gram) are placed in 40 ml of an aqueous solution in which a coloring salt (NiCl.sub.2) is dissolved, for 30 minutes with stirring and then for 5 hours at rest. The concentration of the coloring salt in the solution is 1 mol/L. After centrifugation for 5 minutes at 7000 revolutions/minute and removal of the supernatant solution, the natural talc particles are dried at 120 C. for 12 hours. The talc particles are then rinsed with distilled water, and then the solution is centrifuged for 5 minutes at 9000 revolutions/minute. The supernatant that has been removed is cloudy and green in color. The natural talc particles that are recovered are white. After drying, natural talc particles having a color identical to their original color, that is to say white, are obtained.

(57) A coloring step according to the invention carried out on natural talc particles having a thickness of greater than 100 nm and the largest dimension of which is greater than 10 m therefore does not allow colored silicate mineral particles to be obtained.

(58) C/Structural Analysis and Characterization

(59) In X-ray (XR) diffraction, a natural talc such as a talc from the ARNOLD mine (New York state, USA) is known to exhibit the following characteristic diffraction lines (according to the publication of Ross M., Smith W. L. and Ashton W. H., 1968, Triclinic talc and associated amphiboles from Gouverneur mining district, New York; American Mineralogist, Volume 53, pages 751-769): for the plane (001), a line situated at a distance of 9.34 ; for the plane (002), a line situated at a distance of 4.68 ; for the plane (020), a line situated at a distance of 4.56 ; for the plane (003), a line situated at a distance of 3.115 ; for the plane (060), a line situated at a distance of 1.52 .

(60) The single FIGURE shows the results of analyses carried out by X-ray diffraction obtained with the above compositions.

(61) The diffractograms were recorded on a CPS 120 device marketed by INEL (Artenay, France). This is a diffractometer with a curved detector, allowing detection in real time over an angle domain of 120. The acceleration voltage used is 40 kV and the intensity 25 mA. The Bragg equation giving the structural equidistance is: d.sub.hkl=0.89449/sin (with the use of a cobalt anticathode).

(62) The XR diffractograms of samples 1, 2, 3, 4, 5, 6, 7, 8 and 9 are shown by curves 1, 2, 3, 4, 5, 6, 7, 8 and 9, respectively, of the single FIGURE. Curve 11 of the single FIGURE shows the XR diffractogram of T.O.T.-swelling T.O.T. interlayer particles Si.sub.4Mg.sub.3O.sub.10(OH).sub.2/Si.sub.4Mg.sub.3-O.sub.10(OH).sub.2, (Mg.sup.2+).nH.sub.2O which have not been subjected to a method according to the invention (that is to say before coloring and removal of the aqueous solution: sample 11). These analyses therefore confirm that no new phase is formed during the coloring method according to the invention.

(63) The only differences to be noted between curve 11 and curves 1 to 9 consists in the existence, on curve 11, of lines situated at 370 and at 53 representing the presence of salts obtained from the hydrothermal treatment medium. These salts have been removed in the coloring solution and by rinsing as regards samples 1 to 9.

(64) D/Heat Treatment of T.O.T.-Swelling T.O.T. Interlayer Compositions

(65) A colored T.O.T.-swelling T.O.T. interlayer composition prepared as described above, after drying and grinding, can be subjected to anhydrous heat treatment for a duration of from 30 minutes to 24 hours, especially from 1 hour to 10 hours, and at a temperature of from 300 C. to 600 C., especially from 500 to 550 C. To that end, the composition is placed in a platinum crucible and is then heated. It is also possible to use a crucible made of ceramics or any other suitable material. The reaction is carried out at low pressure, below 5 bar, especially at atmospheric pressure.

(66) The crystalline and lamellar structures of the colored T.O.T.-swelling T.O.T. interlayer particles obtained during and at the end of the implementation of the method defined hereinbefore followed by heat treatment were characterized by X-ray diffraction.

(67) The results of these analyses confirm the possibility of obtaining colored talcose compositions by heat treatment of compositions of colored T.O.T.-swelling T.O.T. interlayer particles. The color of the colored talcose compositions that are obtained remains the same after heat treatment but may be darker than that of the corresponding colored T.O.T.-swelling T.O.T. interlayer particles, before heat treatment.

(68) E/Characterization of the Stability of the Coloring of the Colored Phyllosilicate Mineral Particles According to the Invention

(69) The stability and durability of the coloring of the T.O.T.-swelling T.O.T. interlayer particles Si.sub.4Mg.sub.3O.sub.10(OH).sub.2/Si.sub.4Mg.sub.3-O.sub.10(OH).sub.2, (Mg.sup.2+).nH.sub.2O colored by contacting with MnCl.sub.2 (sample 2) were tested in distilled water.

(70) 1 gram of particles of sample 2 is placed in a beaker containing distilled water. The solution is mixed mechanically for 1 minute and then subjected to ultrasound for 30 seconds. The aqueous solution of brown-colored silicate mineral particles is allowed to rest for 12 hours. After 12 hours without stirring, the brown-colored silicate mineral particles form a deposit at the bottom of the beaker and the supernatant aqueous solution is clear.

(71) It has thus been observed that the dissolution of the colored silicate mineral particles according to the invention does not lead to a loss of the coloration thereof, and that the coloration obtained is stable and durable.

(72) The invention can be the subject of many other applications and of different variants with respect to the embodiment described above. In particular, the element Z can be any other chemical element having a different formula from those which have been mentioned by way of example above and which allow compositions of phyllosilicate mineral particles to be obtained which have different colors from those mentioned above. A plurality of different coloring cations can likewise be used simultaneously in the same coloring solution or in succession.