WO1996031446A1

WO1996031446A1 - A new method for the production of fine powders

Info

Publication number: WO1996031446A1
Application number: PCT/US1996/004676
Authority: WO
Inventors: Ytzhak Yaniv
Original assignee: Baran Advanced Materials (94) Ltd.; Friedman, Mark, M.
Priority date: 1995-04-06
Filing date: 1996-04-03
Publication date: 1996-10-10
Also published as: AU5534796A; ZA962665B; IL113283A0

Abstract

A process for the production of fine powders of inorganic compounds. The process comprises the addition of certain carboxylic acids, or related organic compounds, to the inorganic compounds themselves or to their precursors. The carboxylic acids are either those that cause the foaming of magnesite cement, or those whose aluminum, calcium, or magnesium salts are soluble in water.

Description

APPLICATION FOR PATENT

Title: A NEW METHOD FOR THE PRODUCTION OF FINE POWDERS

FIELD OF THE INVENTION

This invention relates to a new method for the production of improved fine powders of water insoluble or sparingly soluble inorganic materials, including metals such as Al, Cu. Cr. Ni, Fe, Zn. Co, magnesite cements, metal oxides, metal hydroxides, and metal salts, such as carbonates, hydroxycarbonates. sul fates and phosphates. Examples include MgO. Mg(OH)₂, MgO.4SiO₂ H₂O, CaCO₃. MgCO₃, CaMg(CO₃)₂, Ca(OH)₂. Al₂O₃, Al(OH)₃, Fe₂O₃. SiO₂. TiO₂, CaSO₄, Ca₃(PO₄)₂, hydrotalcites like Mg₆Al₂CO₃(OH)_{] 6}4H₂O, and zeolites like Na₈[(AlO₂)₈(SiO₂)₄₀24H₂O and Ca₈[(AlO₂)₄(SiO₂)₈] 13H₂O. This invention lowers the manufacturing cost of these materials in the form of fine powders by enhancing their production rates and allows the production of much smaller particles with much higher surface areas and unexpected crystallographic nature. This invention is particularly important in the production of powders for the paper industry, for the cosmetic industry, for the ceramic industry, for the plastic, paint and rubber industries. etc.

BACKGROUND OF THE INVENTION

The literature is abundant with articles and reviews concerning the importance of minerals in the plastics compounding and in the production of paper. The following reviews: " CaCO^ Fillers - Market Trends and Developments"; J. Revert^' e i Vidal;

Industrial Minerals: November 1994, " Plastic Compounding - Where Mineral Meets Polymer "; M. O'Driscoll; Industrial Minerals: December 1994. " Surface Modification of Mineral Fillers "; R. Goodman; Industrial Minerals; February 1995. " Magnesium Hydroxide Flame Retardant (NHFR) for Plastics and Rubber "; O. Kalisky et al: Chimica Oggi/Chemistry Today; June 1995 and references therein, enlighten the importance of the physical properties, and especially the surface characteristics, of fine powders that are used as fillers in a large variety of applications.

The production and uses of zeolites is reported in numerous papers, patents, reviews and books (e.g. "Zeolite Molecular Sieves - Structure, chemistry and use"; D. W. Breck; by John Wiley & Sons, Inc.; 1974). This patent application may not cover this vast literature that concerns with the art of production of zeolites, except mentioning that these processes are associated with water soluble salts that should be removed from the final products at considerable efforts and costs.

The layered hydrotalcites play, also, a considerable role in the chemical industry. The production of these materials is fraught with difficulty, particular^ with regard to removing large quantities of water-soluble salt impurities from the highly adsorbing small particles of hydrotalcites.

Powders are used intensively in numerous of applications like fillers and flame retardants in paper and plastics industries, like raw materials for ceramics and cements, like constituents in cosmetics, etc.. In order to make effective use of powders, their particle size should be controlled, usually reduced, and their surface properties should be compatible with the substrate with which these powders are to be used.

Grinding or milling of materials are common technologies for size reduction. However, they require high energy expenditure, especially at the sub-micron range.

The high cost of such operations is increased by their low productivity and by the requirement for equipment made of special materials that withstand the high attrition and minimize the contamination of the final fine powders. Generally, two processes are used in the art - dry and wet grinding/milling. In order to increase the production rates of both types of processes and to afford better qualities of grinding/milling, aids. such as dispersants like sodium hexamethaphosphate. etc., are usually employed.

Naturally, wet grinding/milling of soluble materials is preferably carried out in the respective saturated solutions.

Another approach for obtaining fine powders involves their controlled recrystallization or precipitation by means of suitable reactants. A typical example is the formation of CaCO_β , which can be precipitated by reacting e.g. Ca(OH)2 and CO2 in water to form PCC (precipitated calcium carbonate). This technique is relatively more expensive, as it requires the thermal decomposition of CaCO to form

CaO and then the reaction of the CaO in water with CO2. Also, it requires stringent control over the precipitation process to form the desired particle size distribution and to avoid the occlusion of the contaminants from the CaO in the final product. This is usually achieved by slowing down the production rate. Moreover, the crystallographic nature of the Ca(OH)₂ has a considerable effect on the properties of the formed CaCO₃.

Another example is the formation of Mg(OH)2- This material can be produced by hydrolyzing MgO under controlled reaction conditions. Once again, the process requires quite tight control over the precipitation process to form the desired particle size distribution and to avoid the occlusion of the contaminants from the MgO in the final product. This is usually achieved by slowing down the production rate.

The precipitation processes may be conducted in stirred reactors and/or in flotation cells. Thereby, the products (e.g. Mg(OH)2- CaCO3), after in situ proper surface treatment, can be separated from the contaminations at a very low cost. In some cases a combination of controlled recrystallization or precipitation and grinding/milling can be resorted to, albeit with even higher expenses.

CaCO3 is a very important filler in the plastic and paper industries. However. its price and particle characteristics are of prime importance (brightness, surface properties, size distribution, etc.). Indeed PCC is satisfactory for the above purposes. but its price is quite high. Partially calcined dolomite (CaMg(CO3)2) at ~800°C gives rise to MgO.CaCO3. This material is ideally suited to the present invention, as it can be subjected to fast grinding/milling by the addition of the suitable carboxylic acid(s) and brine. The brightness of the MgO will only improve the overall properties of the final fine powder. The savings involved in such a production is considerable compared to PCC or other sources.

Magnesium hydroxycarbonate is a well known flame retardant. This material can be produced, among other methods, by adding CO2 to MgO and/or Mg(OH)2 in aqueous solutions.

SUBSTTTUTE SHEET (RULE 26) The production of zeolites and hydrotalcites is associated with the co- production of large amounts of salts, which affects the cost of the final stage of separation and cleaning of the products. This co-production of large amounts of salts is rather counterproductive, as the zeolites are ionic exchangers and excellent adsorbents. Therefore, any process that will allow the production of zeolites and hydrotalcites without the need to wash, extensively, the products and to waste excessive amounts of precious clean water, may highly affect the economics and the quality of such operations.

The magnesite cements, referred to hereinafter, include magnesium oxychloride cements, having a composition defined by nMgO MgCl2 mH2θ. The art deals with compositions in which n = 3 and m = 1. or in which m = 5 and n = 13. or the like. The present invention is not limited to a specific composition and includes any cement the composition of which comprises MgO and MgCl2- and generally molecular water. The magnesite cements also include oxysulfate cements, the composition of which can be described by the formula m'MgO MgSO_^*. n'H2θ. Various possible values of n' and m' are known in the art. e.g. n' = 5 and m' - 3. The expression "magnesite cements" also includes mixtures of oxychloride and oxysulfate cements.

Obviously, the structure and compositions of the cements change during the curing or hardening process, in manners that are well known to skilled persons and are discussed in the pertinent literature. When magnesium cements are mentioned in this specification and claims, it will be understood that reference is made to cured or uncured or both to cured and uncured cements, as the case may be.

In the specification and claims, the expression "magnesite cement" is intended to include both magnesium oxychloride or Sorel cement, magnesium oxysulfate cement, and mixtures thereof.

We have found that mixing certain organic carboxylic acids, some of which will be listed below, with MgO, MgCl₂ and/or MgSO₄, and water produces porous materials with dramatically reduced densities and high strengths. These materials are referred to herein as "foamed magnesite cements". It is a purpose of the present invention to provide an inexpensive and simple method to produce fine powders of excellent properties.

It is a further purpose of the invention to provide a method to produce these fine powders using common and inexpensive raw materials.

Other purposes and advantages of the invention will appear as the description proceeds.

SUMMARY OF THE INVENTION

Surprisingly, it has been found that the addition to water insoluble or sparingly soluble inorganic materials, like magnesite cements. metals,.metal oxides and/or metal hydroxides and/or metal salts, such as carbonates, sulfates. phosphates, and the like, of organic carboxylic acids (and/or their anhydrides and/or their salts) that are capable of causing the foaming of magnesite cements, greatly improves the production by either grinding/milling or precipitation to produce fine powders, both as to the efficiency of the operation, particularly its speed, and as to quality and crystal lographic nature of the powders obtained. Foamed magnesite cements exhibit the same phenomenon. Non-limitative examples of inorganic materials to which this invention particularly applies are, besides magnesite cements, MgO. dead burned

MgO, Mg(OH)2- MgO-4SiO2'H₂O. CaCO3, Ca(OH)₂. AI2O3, Fe 0₃, Al(OH) . SiO , ZrO , ZrSi0₄. SiC, TiN, MgCO3. Tiθ2, CaSO4. Ca3(Pθ4)2- hydrotalcites like

Mg6AbCO3(OH)₁₆4H₂O, zeolites like Na₈[(Al0 )8(Si0₂)4θ] 24H₂O and

Cag[(Alθ2)4(Siθ2)8] 1 H2O, dolomite, partially calcined dolomite, fly ash. metals like Al. Fe. Co. Ni. Cr, Cu, Zn, etc.. Examples of said carboxylic acids (better defined hereinafter) are decanoic acid, nonanoic acid, octanoic acid. 2-ethylhexanoic acid. heptanoic acid, hexanoic acid, pentanoic acid. 3-methylbutanoic acid, 2- methylpropionic acid, butanoic acid, propionic acid, acrylic acid, methacrylic acid, cyclohexylcarboxN lie acid, isophthalic acid, benzoic acid. 4-t-butylbezoic acid, 4-n- butylbenzoic acid. 2-thiophenecarboxylic acid, 3-thiophenecarboxylic acid and mixtures thereof. Other organic carboxylic acids (and/or their anhydrides and/or their salts), which are capable of solubilizing Ca. Al. and/or Mg ions in aqueous solution, also are effective in improving the production of fine powders, even though these carboxylic acids and related compounds do not cause the foaming of magnesite cements. Among these other carboxylic acids are formic acid, acetic acid, methoxyacetic acid, malic acid, citric acid, gluconic acid, nitrilotriacetic acid (NTAH₃), ethylenediaminetetraacetic acid (EDTAH₄), and the like.

Actually, any material that can liberate the suitable organic carboxylic acid salt(s) in the reaction mixture at the beginning of (or during) the process may lead to similar results. These carboxylic acids and/or their anhydrides and/or their salts may be added to the inorganic materials as such, or together with the other constituents of magnesite cements, namely, MgO, MgCl2 and/or MgSO4 and water. In a preferred form of the invention the inorganic materials to be ground are mixed with a mixture of components from which foamed magnesite cements may be produced. These mixtures may be cured for a short duration and then dry- ground or milled. Wet- grinding or milling of any of the above mixtures does not require curing prior to the grinding/milling. Also, any mixture that does not contain the combination of all the constituents of magnesite cements may not be cured.

Magnesite cements which contain suitable carboxylic acids may also be used as additives for the production of fine powders according to the invention, provided that the carboxylic acid(s) has not been altered (for example, by polymerization) beyond changing into the respective carboxylate(s) that does not foam magnesite cements and/or does not solubilize Mg, Ca. and/or Al ions.

It is to be noted that the addition of the selected carboxylic acid(s) to the aforesaid inorganic materials, according to the invention, need not cause foaming of these latter. The improvement in either the grinding/milling operation or the precipitation operation and in their results does not depend on foaming. Foaming may or may not occur, depending on the particular ingredients used, on the amount of carboxylic acid added, and on other factors. What is essential, on the other hand, is the capability of the acid additive either to produce foaming, if it were used in the production of foamed magnesite cements, or to solubilize Mg, Ca. and/or Al ions in aqueous solution, or to do both. As a result of the invention, the production rates and the quality of the fine powders obtained are improved considerably, as is evidenced by the experimental data that will be set forth hereinafter. It should be noted that the addition of either MgO together with the appropriate carboxylic acid(s), or of the appropriate acid(s) alone. improves the grinding/milling process of the inorganic materials, but to a lesser extent. Therefore it is preferred to use mixtures of suitable carboxylic acids and the components from which magnesite cements may be produced. Nevertheless, the addition of the appropriate carboxylic acid(s) alone to improve the grinding/milling processes may be the only choice, in cases in which contamination of the products with the various constituents of the magnesite cements must be avoided.

The use of the carboxylic acids that lead to foaming of the magnesite cements and/or to solubilizing of Mg, Ca. and/or Al ions in aqueous solution in the grinding/milling or precipitation of the various materials mentioned above, does not exclude the addition of other carboxylic acids (for example, stearic acid, oleic acid. palmitic acid, etc.), polycarboxylic acids and other additives that impart special properties to the surfaces of the produced fine powders. Such additives are known in the art of manufacturing of compatible powders to plastics, paper, etc..

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The organic carboxylic acids have the formula

R-(COOH)_n wherein: n=l and higher

R = H, Alkyl (linear or branched: saturated or unsaturated: cyclic or acyclic); Aryl (substituted or unsubstituted): containing up to 10 carbon atoms in each of its straight chains; wherein one or more of its carbon or hydrogen atoms may be replaced by oxygen, nitrogen, phosphorus or sulfur atoms. The corresponding carboxylic acid anhydrides and/or salts may be used as well.

Carboxylic acid halides of the general formula R(COX)_n. X= Halogens. undergo very fast hydrolysis under the regular conditions of the applications and therefore can be used in this invention. However, their cost is usually somewhat higher than the corresponding carboxylic acids and/or acid anhydrides and/or carboxylate salts and they may contaminate the product with the residual halides, that may have to be washed off the final fine powdered product with a great expense. This is particularly true when porous products are obtained. Effective carboxylic acids chosen according to their ability to solubilize Al,

Ca, or Mg ions should give rise to salts of these metals whose solubility exceeds lg/L at about 25°C. Carboxylic acid salts less soluble than this are defined herein as being "sparingly soluble". Though the desired phenomena are known to take place even in the presence of carboxylic acids that lead to Al, Ca, and/or Mg carboxylates that are sparingly soluble, the process is then too slow and is of no practical consequence.

In a preferred embodiment of the invention, each carboxylic acid is selected from decanoic acid, nonanoic acid, octanoic acid, 2-ethylhexanoic acid, heptanoic acid, hexanoic acid, pentanoic acid, 3-mefhylbutanoic acid, butanoic acid, 2- methylpropanoic acid, propionic acid, acetic acid, formic acid, methoxyacetic acid, acrylic acid, methacrylic acid, isophthalic acid,, malic acid, gluconic acid, benzoic acid, 4-t-butylbenzoic acid, 4-n-butylbenzoic acid, 2-thiophenecarboxylic acid, 3- thiophenecarboxylic acid and mixtures thereof. The efficiency of the acids changes with the size of the R group. For instance, the efficiency of propionic acid and its lower sensitivity to excess amounts of water in the used formulations makes it much superior to that of decanoic acid. However, the decanoic acid leads to higher hydrophobic surfaces and react much milder than the propionic acid. The decision of which acid to use depends on many factors, and particularly on the desired properties of the final products for the specific intended applications.

According to this invention, the carboxylic acid may or may not polymerize. or may partially polymerize, and when it polymerizes it is dimerized and/or oligomerized and/or polymerized, in situ, during the production of the cements, in the presence or the absence of any added polymerization initiators. The expression "added polymerization initiators" should be construed as indicating effective amounts of such initiators which have been deliberately added, to the exclusion of any minor amounts of substances, naturally occurring in the cement components, which may promote some degree of polymerization. It should be noted that polymerizable carboxylic acids, like acrylic and/or methacrylic acids, spontaneously undergo dimerization. oligomerization and/or polymerization, to some extent, under the production conditions. The addition of suitable polymerization initiators (e.g. potassium persulfate, sodium perborate, etc.) substantially enhances this phenomenon and under certain conditions no monomeric residue can be found in the final product. It should be noted that the resulting polymers are unable to foam the magnesite cements. The monomers cause the foaming while undergoing polymerization. In addition, it should be noted that the resulting polymers may not be able to form water soluble Al, Ca and/or Mg salts, though their monomers are able to do so. According to another embodiment of the invention, anhydrides of the carboxylic acids and/or their salts can be employed together and instead of the acids. Examples of illustrative, but non limitative, salts of the carboxylic acids are the Na. K. Mg, Ca, Al. Fe. Cr, Zn, Co, Cu and Ni salts. Other salts will be recognized by the skilled chemist, and are not detailed herein, for the sake of brevity. According to another preferred embodiment of the invention, the cement may further comprise also one or more carboxylic acid(s), polycarboxylic acids and/or their anhydrides and/or their salts, which are not capable of inducing foaming. It should be noted that the general definition of the carboxylic acids above (R-(COOH),,) include examples that do not lead to foaming under the conditions tested, like acetic acid, pyruvic acid, lactic acid, 4-hydroxybutyric acid, malic acid, maleic acid, citric acid, and oxalic acid. The ability of any specific carboxylic acid, within the general group of R-(COOH)_n mentioned above, to produce foaming, should and can easily be checked by the skilled person in each instance. A simple test (out of many others that can be devised by skilled persons) for carrying out such a check will be described as "foaming test" in the experimental section. Clearly, different foaming tests could be devised and it will be easy, for skilled persons, to determine when the addition of an acid produces a cement the density of which is significantly lower than that of a comparable cement prepared without the addition of the acid, showing that this latter is "capable of foaming" the cement. It also should be noted that the general definition of the carboxylic acids (R-

(COOH)_n) include examples that do not lead to water soluble Al. Ca and/or Mg

SUBSTTTUTΕ SHEET (RULE 26) carboxylates. The ability of any specific carboxylic acid, within the general group of R-(COOH)_n, mentioned above, to produce water soluble Al, Ca and/or Mg carboxylates to the extent mentioned above (> 1 g/L) is a necessary condition for the successful and fast production of the desired products. The solubility of the respective Al, Ca and/or Mg carboxylates can easily be measured by the skilled person in each instance or can be looked out in the literature.

The addition of paraffins, polymers, waxes, greases, polyolefins, long chain fatty acid esters, silicone rubbers and other additives to impart hydrophobic surfaces to the fine powders is also well known in the art, and may well be used in the present invention. We also have found that the addition of small amounts of water soluble salts of bivalent and trivalent cations enhances the action of the carboxylic acids of the present invention. Suitable salts include halides, sulfates. silicates, nitrates, organic sulfates, and organic sulfonates of metals such as Mg, Ca, Al, Fe, Zn, Co, Ni, Cu, and Cr. The sequence of addition of the additives to the production process should be checked case by case, as there are different possibilities for optimization.

The addition of elements like Fe, Co, Cu, Ni, Si. Na. K, Cr and/or Zn can be done by using their suitable salts, oxides and hydroxides. Oxygen is usually introduced by using the suitable oxides and/or hydroxides or by the water in which the process is conducted. The C atom in the various mineral structures is either being adsorbed as carbon dioxide gas (e.g. in the air) or by using the suitable carbonates.

In cases at which basic materials should be used to control the pH. a variety of bases like NaOH, KOH, Ca(OH)2, Mg(OH)2, water soluble sodium silicates, ammonia, amines and the like can be used. Ca(OH)2 is rather inexpensive and may suite many applications. The powders of the invention are useful in the same applications as those obtained by prior art processes. The powders may be calcined at the appropriate temperature range to form the corresponding ceramics after losing i.e. CO2 and/or H2O. Examples of such applications are: as fillers or flame retardants in plastics and paper, as fine powders for ceramics and composite materials for special applications, etc..

SUBSTTTUTE SHEET (RULE 26) All the above and other characteristics and advantages of the invention will better be understood from the following illustrative and non limiting description of preferred embodiments, with reference to the examples given below.

Experimental Pata

Raw Materials

In the examples given hereinafter, the following raw materials were used: - Acrylic acid ofAldrich - P-10

- Propionic acid of Aldrich - P-20 - Hexanoic acid of Aldrich - P-40

- 2-Methylpropionic acid ofAldrich - P-50 -Formic acid ofAldrich

-Acetic acid of Aldrich

-E.D.T.A tetra-acid ofAldrich -Gluconic acid of Aldrich

-Malic acid of Aldrich

-Oxalic acid ofAldrich

-Citric acid ofAldrich

-Methacrylic acid ofAldrich -n-Butanoic acid ofAldrich

-n-Octanoic acid ofAldrich

-n-Heptanoic acid ofAldrich

-3-Methylbutanoic acid of Aldrich

-n-Nonanoic acid of Aldrich -n-Decanoic acid ofAldrich

-n-Pentanoic acid ofAldrich

-2-Ethylhexanoic acid ofAldrich

-4-t-Butylbenzoic acid ofAldrich

-Benzoic acid ofAldrich -4-n-Butylbenzoic acid ofAldrich

-Cyclohexylcarboxylic acid ofAldrich

SUB_πTTUTE SHEET (RULE 26) - Palmitic acid ofAldrich

- Stearic acid ofAldrich

- n-dodecanoic acid of Aldrich-Acetic acid of Aldrich -Methoxyacetic acid of Aldrich -Valeric acid ofAldrich

-Oleic acid of Aldrich -Polyacrylic acid of Fluka (#81 140)

-Ethylene Acrylic Copolymer of Allied Signal (Grade A-C540; Lot #095406AC) - Sodium dodecylbenzenesulphonate ofAldrich

- Sodium sulfosuccinate of Cyanamid -AI2O3 H2O - Bohemite of Riedel-de Haen -CaO of Riedel-de Haen

-CO2 adsorbed from the air surrounding the mixing reaction mixtures or from a cylinder of Maxima..

-NaOH of Frutarom

- MgO grade "Normal F" of Grecian magnesite- "MgF"

- MgO of Dead Sea Periclase, Israel - "MgP"

- MgSO4 solution having a density of d=1.2 g/cm-> where the ratio H2O/MgSO4 - 3.1

- MgCb solution having a density of d=l .267-1.27 g/cm^ where the ratio H2O/MgCl2=2.61

- CaCO3 powder (d5o=18 microns) of Polychrom. Israel- "Girulite-40"

Example 1

Magnesium Oxychloride and Oxysulphate - Dry Grinding Process

The materials in Table 1 were mixed in a laboratory mixer for about 10 minutes.

Table 1

The resulting mixtures were pelletized and allowed to cure at ambient temperature for eight days. The hardened products were introduced into a laboratory grinding machine (hammer mill) for ten minutes, and the resulting powders, respectively, were sieved. The size distribution is given in Table 2.

Table 2

Weight (%) - Size Distribution in mesh

Type + 14 mesh 14+50 mesh -50+100 mesh 100+200 mesh -200 mesh

] 50.0 35.0 15.0 - -

2 53.0 32.0 12.0 3.0 -

3 - - 4.0 35.0 61.0

4 - - 5.0 40.0 55.0

5 - - 2.0 31.0 67.0

6 - - 8.0 37.0 55.0

7 - - 9.5 42.0 48.5 Example 2

Production of CaCO Powders hv Wet Grinding Process

The grinding was carried out in a laboratory ball mill (mill volume 3 L; Alumina balls of density of 4.0 g/cc; balls volume = 1.2 L). The raw materials listed in Table 3 were loaded into the ball mill.

Table 3

Notes: 1. The grinding efficiency for CaCO3 would have been higher for slurries containing higher solid concentrations then 56% (wt). The optimal solid concentration is 70%

(wt).

2. In cases at which MgO and a magnesium salt solution are present, the formation of the magnesite cements increase the overall solids concentration. 3. Test 8 is a comparative test, since no carboxylic acid was used in it.

The grinding lasted 24 hours and samples were taken after 2. 4. 6, and 24 hours for particle size distribution and for surface area measurements. The results are given in Table 4

Table 4

Test 1 1

Sampling Time hrs) d«;n (microns) Spec. Surface Area (cm g)

0 18.0 4,330

2 3.93 13,921

4 3.88 16,547

6 3.18 18,223

24 1.64 22,495

Test 12

Sampling Time (hrs) d,₀ (microns) Spec. Surface Area (cm7g)

0 18.0 4,330

2 3.60 15,837

4 2.30 19.107

6 1.85 21 , 103

24 1.38 26,450

Notes:

1. The particle sizes are smaller and the surface area is larger in tests 9-12 than those of test 8, though the opposite would have been expected, since the solid concentration in the slurry is higher is test 8.

2. Test 9 leads to the best results (MgO + magnesium chloride solution + Carboxylic acid).

3. The addition of a carboxylic acid only ( test 1 1 ) leads to better results than those obtained without any additive (test 8). However, the improvement is delayed for -6 Hs.

SUBSTTTUTE SHEET (RULE 26) Example 3

Production of Magnesite Cements Powders - Flame Retarding Materials

The -200 mesh powder which was obtained in test 4 was dried over-night in a oven at 120°C. The dry powder released 33% (wt) water at ~350°C on a TGA analysis._The Magnesite fine powder that was obtained in the above Example may be added to polymers and other materials as a flame retarding agent. This powder and similar ones are superior over Al(OH)3 (A.T.H), as they may be used to process polymers, which require operation at temperatures above 200°C.

Example 4

"Foaming Test"

Cement mixtures consisting of the following materials: 60g MgO ("MgF"), 90g MgCl2 brine, 50g quartz sand and the 3.0g of the organic carboxylic acid being tested, are mixed in a laboratory mixer (Retch type KM-=1 ) for 10 mins.. The mixtures obtained are cast into dies of the dimensions 40x40x160 mm and allowed to cure at room temperature and pressure for 10 days. The specimens are dried at 80°C for 15 hrs. and then their densities are measured. The results are given in Table 5

Table 5

Test # Caboxvlic Acid Density g/cm³) Notes

9 None 1.95 Reference

10 Stearic >1.85 Non-Foaming

1 1 Palmitic >1.85 Non-Foaming

12 Dodecanoic >1.85 Non-Foaming

13 Formic 1.92 Non-Foaming

14 Acetic 1.94 Non-Foaming

15 E.D.T.A 1.93 Non-Foaming

16 Gluconic 1.95 Non-Foaming

17 Malic 1.94 Non-Foaming

18 Oxalic 1.92 Non-Foaming

19 Citric 1.93 Non-Foaming

20 Polvacrylic 1.92 Non-Foaming

21 Ethylene Acrylic Copolymer 1.94 Non-Foaming

22 Acrylic 0.95 Foaming 23 Methacrylic 0.99 Foaming

24 Propionic 0.82 Foaming

25 n-Butanoic 1.15 Foaming

26 n-Hexanoic 1.23 Foaming

27 2-Methylpropionic 1.18 Foaming

28 n-Octanoic 1.27 Foaming

29 n-Heptanoic 1.30 Foaming

30 3-Methvlbutanoic 1.40 Foaming

31 n-Nonanoic 1.39 Foaming

32 n-Decanoic 1.45 Foaming n-Pentanoic 0.93 Foaming

34 2-Ethvlhexanoic 1.28 Foaming

35 4-t-Butvlbenzoic 1.12 Foaming

36 Benzoic 0.99 Foaming

37 4-n-Butvlbenzoic 1.32 Foaming

38 Cyclohexylcarboxylic 0.88 Foaming

Note 1 : A carboxylic acid is considered capable of foaming the magnesite cement if it produces the said material, according to the above procedure, of a density lower than

1.85 g/cm^ and preferably lower than 1.80 g/cm

Note 2: Sodium dodecylbenzenesulphonate and sodium dioctylsulfosuccinte gave rise to cements of >1.85 g/cm^ when tested under the above conditions.

Example 5

Hydrolysis of MgO to Form Precipitated MgfOHb

MgO powder was hydrolyzed in the presence of the suitable additives in a glass reactor at 50°C while stirring magnetically at 200 rpm for 0.5 hr. The slurry was then filtered and the white product was washed and dried at 120°C for 24 hrs. The dry cake was disintegrated into a fine powder product in a laboratory Retch mill for a short period. The fine powder was analyzed in the following manner: a. The loss on ignition (%LOI) of 15g was measured at 400°C for 4 hrs in a ceramic crucible. The %conversion of the MgO to Mg(OH)2- was calculated based on the fact that the pure product should contain 30.87% water (%LOI). b. The loose bulk density (LBD) was measured in a 100ml graduated cylinder. The fine powder was introduced into the cylinder and was shaken for 3mins on a screen

SUBSTTTUTΕ SHEET (RULE 26) shaker. The LBD was then calculated by dividing the weight of the powder by its volume in the cylinder. c. The moφhologic characteristics of the product (1. The crystal shapes, 2. The crystal sizes: the length - D (the diagonal in the case of hexagonal crystals), the width - d and the aspect ratio (AR) - D/d, were measured by a SEM.

The results of the experiments are given in Tables 6 and 7:

Table 6

eight (β) Type of Material

# Water MgO Brine arboxylic A. Brine Carboxylic A. No,e 9 400 100 - - - - Reference a 400 100 - 1.5 - Oleic Reference 0 400 100 3.0 1.5 MgCb Propionic 1 400 100 3.0 1.5 MgSO4 Propionic 2 400 100 3.0 1.5 MgSO4 Acetic 3 400 100 3.0 1.5 MgSO4 Acrylic 4 400 100 3.0 1.5 MgSO4 Valeric 5 400 100 3.0 1.5 MgSO₄ Methoxyacetic 6 400 100 - 1.5 - Propionic Reference 7 400 100 - 1.5 - Acetic Reference

Table 7

%LOI LBD Conversion Crystal Length Thickness AR

# 400^υC g/cc % M (OH)-> Shape D(micron) d (micron) D/d

39 22.0 0.441 71.2 Trigonal 0.6-0.8 0.6-0.8 1.0

39a 22.0 0.441 71.2 ^• Trigonal 0.6-0.8 0.6-0.8 1.0

40 29.0 0.367 93.9 Hexagonal 0.6 0.4-0.6 1.0- 1.5

41 29.8 0.343 96.5 Hexagonal 0.8- 1.0 0.1 -0.2 4.0-10.0

42 27.5 0.366 89.1 Hexagonal 0.5-0.6 0.2-0.3 1.6-3.0

43 29.3 0.347 94.9 Hexagonal 1.5-2.0 0.1-0.2 7.5-20.0

44 9.2 0.348 94.6 Hexagonal 0.3-0.4 0.2-0.3 1.0-2.0

45 8.8 0.371 93.3 Hexagonal 0.6-0.8 0.2-0.3 2.0-4.0

46 9.4 0.356 95.2 Hexagonal 0.6-0.8 0.2-0.3 2.0-4.0

47 6.8 0.432 86.3 Hexagonal 0.8- 1.0 0.2 2.0-4.0 Remarks;

1. MgO of Dead Sea Periclase, Israel - "MgP".

2. In the absence of brine or water soluble Mg-carboxylates the trigonal shape results.

3. In the presence of brine and/or water soluble Mg-carboxylates the hexagonal shape results. The crystal sizes and shapes are dramatically affected by the kind of brine and carboxylates used.

4. The crystallographic nature of the product may be altered by either impurities that are present in the raw material or by deliberately adding known crystal habit modifiers, other than the suitable carboxylates. This is especially true when raw materials of different manufacturers are used.

Example 6

Hydrolysis of Bohemite (AI2O3Η2OI to Form Mg₆AbCO3⁽OH⁾ _{1 6}'4H2O - Precipitated Hydrotalcite (HP

A slurry of bohemite powder in water was hydrolyzed in the presence of the suitable additives in a glass reactor at 70°C while stirring magnetically at 200 φm for 0.5 hr.

The slurry was then filtered and the white product was washed and dried at 120°C for 24 Hrs. The dry cake was disintegrated into a fine powder product in a laboratory Retch mill for a short period. The fine powder was analyzed in the following manner: a. The loss on ignition (%LOI) of 15g was measured at 300°C for 4 hrs in a ceramic crucible (Note: The %LOI of the following pure materials are: Mg(OH)2 - 30. 87:

Ab_O H₂O -14.5; Al(OH)₃ - 34.6). b. The crystallographic characteristics of the products were determined using XRD and SEM.

The results of the experiments are given in Table 8:

SUBSTTTUTE SHEET (RULE 26) Table 8

Example 7

Hydrolysis of CaO to Form Precipitated Ca(OH

CaO powder was hydrolyzed in the presence of the suitable additives in a glass reactor at 20°C- 22°C while stirring magnetically at 200 rpm for 20 mins. The pH in all the tests was above 12. The slurry was then transferred into a settling columns to determine the linear settling rate, which is proportional to the particles^" size (cf A. M. Gaudin; "Principles of Mineral Dressing^": McGraw Hill. !939: Page 172 and W. P. Talmage and E. B. Fitch: "Determining of Thickener Unit Areas^": Industrial and Engineering Chemist: Vol. 47. No. 1 : January. 1955; pp 38-41 ) The results of the experiments are given in Table 9: Table 9

Weight (B) Type of Ho H„ Linear Settling Rate

# Water CaO CM CM ml ml l/hr

57 200 20 - - 210 80.0 160 (Reference)

58 200 20 1.0 Propionic 210 1 10.0 70

59 200 20 1.0 Acetic 210 100.0 1 10

60 200 20 1.0 Acrylic 210 105.0 90

Remarks:

1. H₀ - is the initial height of the liquid solid surface. 2. H-j - is the ultimate height of the liquid/solid surface after 24 hrs

3. CM - Carboxylic acids or carboxylates

4. The addition of carboxylates cause the reduction of the particle size.

Example 8 Production of Precipitated CaCO3

CaO. water, carbon dioxide and certain carboxylic acids (CM.) were stirred magnetically in a 0.6 Lit. flask for 30 mins. at 30 C. The solid was collected by filtration and dried for 24 hrs. at 1 10°C The dry product was disintegrated with a laboratory retch mill. The products were analyzed by SEM and XRD to characterize their properties. The reaction conditions and the properties of the products are given in the following tables 10 and 1 1 :

Table 10

Weisht (g) Type of Initial Final

# Water CaO CM. CM. PH PH

61 300 28 - - > 1 1 ~ 10.5

62 300 28 2.0 Propionic > 1 1 7 - 8

63 300 2S 2.0 Acetic > 1 1 7 - 8

64 300 28 2.0 Propionic > 1 1 7 - 8 Remarks:

1. Excess CO_: was added to all the tests from a cylinder. CaO + H₂0 CO₂ > CaCO₃

2. 0.5g of MgO was added to test 26 to control the pH.

SUBSTTTUTE SHEET (RULE 26) Table 11

# Major Mineralogic Phases (XRD) Crystal Shape & Size (SEM) Remark

61 Ca(OH)₂ - Major - Reference Ca,(CO-,),(OH), 1.5H,0 - Minor

62 CaC0₃ - Calcite Round - Diameter: 0.1 - 0.2 μ

63 CaC0₃ - Calcite Cubic Like - Size: 0.6 - 1.0 μ

64 CaC0₃ - Calcite Round - Diameter: 0.2 - 0.3 μ

Remark;

The crystallographic nature of the product may be altered by either impurities that are present in the raw material or by deliberately adding known crystal habit modifiers, other than the suitable carboxylates. This is especially true when raw materials of different manufacturers are used.

Example 9

Production of Magnesium Hydroxycarhonate

The experimental conditions of the former example were repeated at 25 -O^WrC using calcined MgO. The products were analyzed by SEM and XRD to characterize their properties. The reaction conditions and the properties of the products are given in the following tables 12 and 13:

Table 12

Weight (B) Type of Initial Final

_. Water MgO CM. CM. PH H

65 300 20 - - ~ 10 9 - 10

66 300 20 2.0 Propionic ~ 10 7 - 8

6⁷ 300 20 2.0 Acetic ~ 10 7 - 8

Remark: 1. Excess CO₂ was added to all the tests from a cylinder. MgO + H₂O + CO₂ > MgCO₃ Table 13

Major Mineralogic Phases (XRD) Crystal Shape & Size (SEM) Remark

65 MgO - Periclase - Reference Mg(OH), - Brucite

66 Mg₄(C0₃)₃(OH)₂ 3H₂0 Platelets - Hydromagnesite Size: 1.0 μ ; Thickness: 0.1 μ

67 Mg₄(C0₃)₃(OH)₂ 3H₂0 Platelets - Hydromagnesite Size: 0.5 μ ; Thickness: 0.1 μ

Remark:

While preferred embodiments of the invention have been described by way of illustration, it will be apparent that the invention can be carried out by persons skilled in the art with many modifications, variations and adaptations, without departing from its spirit or exceeding its scope.

Claims

WHAT IS CLAIMED IS:

1. A process for the production of fine powders, comprising the step of adding, to at least one inorganic material, at least one additive selected from the group consisting of carboxylic acids that are capable of causing the foaming of magnesite cements, anhydrides of said carboxylic acids, salts of said carboxylic acids, acyl halides of said carboxylic acids, foamed magnesite cement made using said carboxylic acids, foamed magnesite cement made using said anhydrides of said carboxylic acids, foamed magnesite cement made using said salts of said carboxylic acids, and foamed magnesite cement made using said acyl halides of said carboxylic acids.

2. The process of claim 1, wherein said at least one inorganic material is selected from the group consisting of magnesite cements, metals, metal oxides, metal hydroxides, metal salts, metal carbides, and metal nitrides.

3. The process of claim 2. wherein said at least one inorganic material is selected from the group consisting of Al, Cu, Cr, Ni, Fe, Zn. Co, MgO, Mg(OH)₂, MgO4SiO₂ H₂O. CaCO₃, Ca(OH)₂. Al₂O₃, Al(OH)₃. SiO₂. Zr0₂. ZrSiO₄, SiC, TiN, MgCO₃, TiO₂, CaSO₄, Ca₃(PO₄)₂, dolomite, partly calcined dolomite, magnesite cement, and fly ash.

4. The process of claim 3, wherein said at least one inorganic material includes MgO.

5. The process of claim 1 , further comprising the step of precipitating said at least one inorganic material.

6. The process of claim 1. further comprising the step of wet-grinding said at least one inorganic material.

7. The process of claim 1 , further comprising the step of dry-grinding said at least one inorganic material.

8. The process of claim 1 , wherein said carboxylic acids have the formula

R-COOH wherein R is selected from the group consisting of H, linear saturated alkyl having up to ten carbon atoms, linear unsaturated alkyl having up to ten carbon atoms, branched saturated alkyl having up to ten carbon atoms in the longest branch thereof, branched unsaturated alkyl having up to ten carbon atoms in the longest branch thereof, cyclic unsubstituted saturated alkyl, cyclic substituted saturated alkyl wherein the longest branch of said at least one substituent has at most ten carbon atoms, cyclic unsubstituted unsaturated alkyl. cyclic substituted unsaturated alkyl wherein the longest branch of said at least one substituent has at most ten carbon atoms, unsubstituted aryl. and substituted aryl wherein the longest branch of said at least one substituent has at most ten carbon atoms.

9. The process of claim 8, wherein said carboxylic acids are selected from the group consisting of decanoic acid, nonanoic acid, octanoic acid. 2-ethylhexanoic acid, heptanoic acid, hexanoic acid, pentanoic acid. 3-methylbutanoic acid, 2- methylpropanoic acid, butanoic acid, propionic acid, acrylic acid, methacrylic acid, cyclohexylcarboxyϋc acid, benzoic acid, 4-t-butylbenzoic acid, and 4-n-butyl benzoic acid.

10. The process of claim 8, wherein at least one atom of said R, selected from the group consisting of carbon and hydrogen, is replaced by at least one atom selected from the group consisting of oxygen, nitrogen, phosphorus, and sulfur.

1 1. The process of claim 10. wherein said carboxylic acids are selected from the group consisting of 2-thiophenecarboxylic acid and 3-thiophenecarboxylic acid.

12. The process of claim 1, further comprising the step of adding MgO.

13. The process of claim 12, further comprising the step of adding water and at least one magnesium salt selected form the group consisting of MgCl₂ and MgSO₄.

14. The process of claim 13, further comprising the steps of:

(a) curing said inorganic material; and

(b) dry-grinding said inorganic material.

15. The process of claim 1 , further comprising the steps of:

(a) curing said inorganic material; and

(b) dry-grinding said inorganic material.

16. The process of claim 1, further comprising the step of adding at least one additional additive selected from the group consisting of nonfoaming carboxylic acids, anhydrides of said nonfoaming carboxylic acids, acyl halides of said nonfoaming carboxylic acids, salts of said nonfoaming carboxylic acids, polycarboxylic acids, anhydrides of said polycarboxylic acids, salts of said polycarboxylic acids, and acyl halides of said polycarboxylic acids.

17. The process of claim 1, further comprising the step of adding at least one additional additive capable of imparting a hydrophobic surface to the fine powder.

18. The process of claim 17, wherein said at least one additional additive is selected from the group consisting of polymers, paraffins, and silicone rubber.

19. The process of claim 1. further comprising the step of adding at least one polymerization initiator to said inorganic material.

20. The process of claim 1, wherein said salts of said carboxylic acids are selected from the group consisting of sodium salts of said carboxylic acids, magnesium salts of said carboxylic acids, calcium salts of said carboxylic acids, and aluminum salts of said carboxylic acids.

21. A fine powder produced by adding, to at least one inorganic material, at least one additive selected from the group consisting of carboxylic acids that are capable of causing the foaming of magnesite cements, anhydrides of said carboxylic acids, salts of said carboxylic acids, acyl halides of said carboxylic acids, foamed magnesite cement made using said carboxylic acids, foamed magnesite cement made using said anhydrides of said carboxylic acids, foamed magnesite cement made using said salts of said carboxylic acids, and foamed magnesite cements made using said acyl halides of said carboxylic acids.

22. The fine powder of claim 21, wherein said inorganic material is selected from the group consisting of magnesite cements, metals, metal oxides, metal hydroxides, metal salts, metal carbides, and metal nitrides.

23. The fine powder of claim 22, wherein said at least one inorganic material is selected from the group consisting of Al, Cu, Cr, Ni, Fe, Zn, Co. MgO. Mg(OH)₂. MgO4SiO₂ H₂O, CaCO₃, Ca(OH)₂, Al₂O₃, Al(OH)₃, SiO₂, ZrO₂, ZrSiO₄. SiC, TiN. MgCO₃, TiO₂, CaSO₄, Ca₃(PO ) , dolomite, partly calcined dolomite, magnesite cement, and fly ash.

24. The fine powder of claim 23, wherein said inorganic material includes MgO.

25. The fine powder of claim 21. wherein said at least one inorganic material is precipitated.

26. The fine powder of claim 21. wherein said at least one inorganic material is wet-ground.

27. The fine powder of claim 21, wherein said at least one inorganic material is dry-ground.

28. The fine powder of claim 21, wherein said carboxylic acids have the formula

R-COOH wherein R is selected from the group consisting of H, linear saturated alkyl having up to ten carbon atoms, linear unsaturated alkyl having up to ten carbon atoms, branched saturated alkyl having up to ten carbon atoms in the longest branch thereof, branched unsaturated alkyl having up to ten carbon atoms in the longest branch thereof, cyclic unsubstituted saturated alkyl, cyclic substituted saturated alkyl wherein the longest branch of said at least one substituent has at most ten carbon atoms, cyclic unsubstituted unsaturated alkyl, cyclic substituted unsaturated alkyl wherein the longest branch of said at least one substituent has at most ten carbon atoms, unsubstituted aryl. and substituted aryl wherein the longest branch of said at least one substituent has at most ten carbon atoms.

29. The fine powder of claim 28, wherein said carboxylic acids are selected from the group consisting of decanoic acid, nonanoic acid, octanoic acid, 2- ethylhexanoic acid, heptanoic acid, hexanoic acid, pentanoic acid, 3-methylbutanoic acid, 2-methylpropanoic acid, butanoic acid, propionic acid, acrylic acid, methacrylic acid, cyclohexylcarboxylic acid, benzoic acid, 4-t-butylbenzoic acid, and 4-n- butylbenzoic acid.

30. The fine powder of claim 28, wherein at least one atom of said R, selected from the group consisting of carbon and hydrogen, is replaced by at least one atom selected from the group consisting of oxygen, nitrogen, phosphorus, and sulfur.

31. The fine powder of claim 30. wherein said carboxylic acids are selected from the group consisting of 2-thiophenecarboxylic acid and 3-thiophenecarboxylic acid.

32. The fine powder of claim 21, wherein MgO is added to said at least one inorganic material.

33. The fine powder of claim 32, wherein water and at least one magnesium salt selected form the group consisting of MgCl₂ and MgSO are added to said at least one inorganic material.

34. The fine powder of claim 33, wherein said at least one inorganic material is cured and dry-ground.

35. The fine powder of claim 21 , wherein said at least one inorganic material is cured and dry-ground.

36. The fine powder of claim 21 , further comprising the step of adding at least one additional additive selected from the group consisting of nonfoaming carboxylic acids, anhydrides of said nonfoaming carboxylic acids, acyl halides of said nonfoaming carboxylic acids, salts of said nonfoaming carboxylic acids, polycarboxylic acids, anhydrides of said polycarboxylic acids, salts of said polycarboxylic acids, and acyl halides of said polycarboxylic acids.

37. The fine powder of claim 21 , wherein at least one additional additive is added to said at least one inorganic material, said at least one additional additive being capable of imparting a hydrophobic surface to the fine powder.

38. The fine powder of claim 37, wherein said at least one additional additive is selected from the group consisting of polymers, paraffins, and silicone rubber.

39. The fine powder of claim 21. wherein at least one polymerization initiator is added to said inorganic material.

40. The fine powder of claim 21, wherein said salts of said carboxylic acids are selected from the group consisting of sodium salts of said carboxylic acids, magnesium salts of said carboxylic acids, calcium salts of said carboxylic acids, and aluminum salts of said carboxylic acids.

41. A process for the production of a fine powder from a mixture that includes water and at least one inorganic material, comprising the step of adding to the mixture at least one additive selected from the group consisting of carboxylic acids whose salts with cations selected from the group consisting of Al⁺⁺⁺. Ca⁺⁺, and Mg are soluble to an extent greater than about lg/L in water at a temperatαre of about 25°C anhydrides of said carboxylic acids, salts of said carboxylic acios, and acyl halides of said carboxylic acids.

42. The process of claim 41, wherein the mixture includes at least one inorganic compound containing at least one element selected from the group consisting of Al, Ca, Mg, Fe, Zn, Co, Ni, Cu, Si, Ti, Na. K, C, N, and Cr.

43. The process of claim 42, wherein said at least one inorganic compound containing carbon is selected from the group consisting of carbon dioxide and carbonates.

44. The process of claim 41, wherein the at least one inorganic material is selected from the group consisting of magnesite cements, metals, metal oxides, metal hydroxides, metal salts, metal carbides, and metal nitrides.

45. The process of claim 44, wherein the at least one inorganic material is selected from the group consisting of magnesite cements.

46. The process of claim 44, wherein said at least one metal is selected from the group consisting of Al, Cu, Cr, Ni. Fe, Zn. and Co.

47. The process of claim 44, wherein said at least one metal oxide is selected from the group consisting of MgO, MgO 4SiO₂ H2O, Al₂O₃. SiO₂, ZrO₂, and TiO₂.

48. The process of claim 44, wherein said at least one metal hydroxide is selected from the group consisting of Mg(OH)₂, Ca(OH)₂, and Al(OH)₃..

49. The process of claim 44, wherein said at least one metal salt is selected from the group consisting of CaCO₃, ZrSiO₄, MgCO₃, CaSO₄, Ca₃(PO )₂, dolomite, and partly calcined dolomite.

50. The process of claim 41 , wherein the at least one inorganic material is fly ash.

51. The process of claim 41, wherein the mixture includes at least one water-soluble salt containing:

(a) at least one cation selected from the group consisting of bivalent cations and, trivalent cations and

(b) at least one anion selected from the group consisting of halide, nitrate, silicates, sulfate. organic sulfates, and organic sulfonates.

52. The process of claim 51, wherein said at least one cation is selected from the group consisting of Mg⁺⁺, Ca , Al⁺⁺⁺, Fe⁺⁺, Fe ⁺, Zn . Co Co⁺⁺⁺, Ni⁺⁺. Cu . Cr⁺⁺, and Cτ^→ .

53. The process of claim 41, wherein said carboxylic acids have the formula

R-(COOH)_n wherein n is a positive integer and R is selected from the group consisting of H. linear saturated alkyl having up to ten carbon atoms, linear unsaturated alkyl having up to ten carbon atoms, branched saturated alkyl having up to ten carbon atoms in the longest branch thereof, branched unsaturated alkyl having up to ten carbon atoms in the longest branch thereof, cyclic unsubstituted saturated alkyl, cyclic substituted saturated alkyl wherein the longest branch of said at least one substituent has at most ten carbon atoms, cyclic unsubstituted unsaturated alkyl, cyclic substituted unsaturated alkyl wherein the longest branch of said at least one substituent has at most ten carbon atoms, unsubstituted aryl, and substituted aryl wherein the longest branch of said at least one substituent has at most ten carbon atoms.

54. The process of claim 53, wherein said carboxylic acids are selected from the group consisting of decanoic acid, nonanoic acid, octanoic acid, 2- ethylhexanoic acid, heptanoic acid, hexanoic acid, pentanoic acid, 3 -methyl butanoic acid, 2-mefhylpropionic acid, butanoic acid, propionic acid, acetic acid, methoxyacetic acid, formic acid, acrylic acid, methacrylic acid, cyclohexylcarboxylic acid, benzoic acid. 4-t-butylbenzoic acid. 4-n-butylbenzoic acid, malic acid, citric acid, gluconic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, and valeric acid.

55. The process of claim 53, wherein at least one atom of said R, selected from the group consisting of carbon and hydrogen, is replaced by at least one atom selected from the group consisting of oxygen, nitrogen, phosphorus, and sulfur.

56. The process of claim 55, wherein said carboxylic acids are selected from the group consisting of 2-thiophenecarboxylic acid and 3-thiophenecarboxylic acid.

57. The process of claim 41 , wherein said carboxylic acid salts are selected from the group consisting of Na carboxylates. K carboxylates. Mg carboxylates, Ca carboxylates. Al carboxylates. Fe carboxylates, Zn carboxylates. Co carboxylates. Ni carboxylates. Cu carboxylates, and Cr carboxylates.

SUBSTTTUTE SHEET (RULE 26)

58. The process of claim 41, further comprising the step of adding to the mixture at least one additive selected from the group consisting of carboxylic acids whose salts with cations, selected from the group consisting of Ca , Mg^"1^, and Al⁺⁺⁺, are sparingly soluble in water, anhydrides of said carboxylic acids, salts of said carboxylic acids, acyl halides of said carboxylic acids, polycarboxylic acids whose salts with cations, selected from the group consisting of Ca^, Mg^. and Al⁺⁺⁺, are sparingly soluble in water, anhydrides of said polycarboxylic acids, salts of said polycarboxylic acids, and acyl halides of said polycarboxylic acids.

59. The process of claim 41 , further comprising the step of adding to the mixture at least one additive selected from the group consisting of polymers, waxes, and greases.

60. The process of claim 41, further comprising the step of adding to the mixture at least one additive selected from the group consisting of polyolefins, paraffins, long chain fatty acid esters, and silicone rubbers.

61. The process of claim 41 , further comprising the step of adding to the mixture at least one polymerization initiator.

62. The process of claim 41 , further comprising the step of adding to the mixture at least one basic material.

63. The process of claim 62. wherein said at least one basic material is selected from the group consisting of NaOH, KOH. Ca(OH)₂, Mg(OH)₂. water soluble sodium silicates, ammonia, and amines.

64. The process of claim 41. further comprising the step of grinding said mixture.

65. The process of claim 41, wherein the fine powder precipitates from said mixture.

66. The process of claim 65, wherein said precipitation occurs in a stirred reactor.

67. The process of claim 65, wherein said precipitation occurs in a flotation cell.

68. The process of claim 41, wherein the fine powder includes at least one inorganic compound selected from the group consisting of Mg(OH)₂, Al OH)₃, Ca(OH)₂, CaCO₃, hydrotalcites, and zeolites.

69. A fine powder produced from a mixture that includes water and at least one inorganic material, by adding to the mixture at least one additive selected from the group consisting of carboxylic acids whose salts with cations selected from the group consisting of Al⁺⁺⁺, Ca⁺⁺, and Mg are soluble to an extent greater than about lg/L in water at a temperature of about 25°C, anhydrides of said carboxylic acids, salts of said carboxylic acids, and acyl halides of said carboxylic acids.

70. The fine powder of claim 69, wherein the mixture includes at least one inorganic compound containing at least one element selected from the group consisting of Al, Ca, Mg, Fe, Zn, Co, Ni, Cu, Si, Ti, Na, K, C. N, and Cr.

71. The fine powder of claim 70, wherein said at least one inorganic compound containing carbon is selected from the group consisting of carbon dioxide and carbonates.

72. The fine powder of claim 69, wherein the at least one inorganic material is selected from the group consisting of magnesite cements, metals, metal oxides, metal hvdroxides, metal salts, metal carbides, and metal nitrides.

SUBSTTTUTE SHEET (RULE 26)

73. The fine powder of claim 72, wherein the at least one inorganic material is selected from the group consisting of magnesite cements.

74. The fine powder of claim 72, wherein the at least one metal is selected from the group consisting of Al, Cu, Cr, Ni, Fe, Zn, and Co.

75. The fine powder of claim 72, wherein said at least one metal oxide is selected from the group consisting of MgO, MgO4SiO₂ H₂O, Al O₃. SiO₂, ZrO₂, and TiO₂.

76. The fine powder of claim 72, wherein said at least one metal hydroxide is selected from the group consisting of Mg(OH)₂, Ca(OH)₂, and Al(OH)₃.

77. The fine powder of claim 72, wherein said at least one metal salt is selected from the group consisting of CaCO₃, ZrSiO₄. MgCO , CaSO₄, Ca₃(PO₄)₂. dolomite, and partly calcined dolomite.

78. The fine powder of claim 69, wherein the at least one inorganic material is fly ash.

79. The fine powder of claim 69, wherein the mixture includes at least one water-soluble salt containing:

(a) at least one cation selected from the group consisting of bivalent cations and trivalent cations, and

80. The fine powder of claim 79, wherein said at least one cation is selected from the group consisting of Mg ⁺, Ca^{^} , Al \ Fe ⁺, Fe ⁺ , Zn , Co⁺⁺.

81. The fine powder of claim 69, wherein said carboxylic acids have the formula

R-(COOH)_n wherein n is a positive integer and R is selected from the group consisting of H, linear saturated alkyl having up to ten carbon atoms, linear unsaturated alkyl having up to ten carbon atoms, branched saturated alkyl having up to ten carbon atoms in the longest branch thereof, branched unsaturated alkyl having up to ten carbon atoms in the longest branch thereof, cyclic unsubstituted saturated alkyl, cyclic substituted saturated alkyl wherein the longest branch of said at least one substituent has at most ten carbon atoms, cyclic unsubstituted unsaturated alkyl, cyclic substituted unsaturated alkyl wherein the longest branch of said at least one substituent has at most ten carbon atoms, unsubstituted aryl. and substituted aryl wherein the longest branch of said at least one substituent has at most ten carbon atoms.

82. The fine powder of claim 81, wherein said carboxylic acids are selected from the group consisting of decanoic acid, nonanoic acid, octanoic acid, 2- ethylhexanoic acid, heptanoic acid, hexanoic acid, pentanoic acid, 3-methylbutanoic acid, 2-methylpropionic acid, butanoic acid, propionic acid, acetic acid, methoxyacetic acid, formic acid, acrylic acid, methacrylic acid, cyclohexylcarboxylic acid, benzoic acid, 4-t-butylbenzoic acid. 4-n-butylbenzoic acid, malic acid, citric acid, gluconic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, and valeric acid.

83. The fine powder of claim 81 , wherein at least one atom of said R, selected from the group consisting of carbon and hydrogen, is replaced by at least one atom selected from the group consisting of oxygen, nitrogen, phosphorus, and sulfur.

84. The fine powder of claim 83, wherein said carboxylic acids are selected from the group consisting of 2-thiophenecarboxylic acid and 3- thiophenecarboxylic acid.

85. The fine powder of claim 69, wherein said carboxylic acid salts are selected from the group consisting of Na carboxylates, K carboxylates, Mg carboxylates, Ca carboxylates, Al carboxylates, Fe carboxylates, Zn carboxylates, Co carboxylates, Ni carboxylates, Cu carboxylates, and Cr carboxylates.

86. The fine powder of claim 69, wherein at least one additive selected from the group consisting- of carboxylic acids whose salts with cations, selected from the group consisting of Ca⁺⁺, Mg^, and Al^{+ +}, are sparingly soluble in water, anhydrides of said carboxylic acids, salts of said carboxylic acids, acyl halides of said carboxylic acids, polycarboxylic acids whose salts with cations, selected from the group consisting of Ca++, Mg++, and A1+++, are sparingly soluble in water, anhydrides of said polycarboxylic acids, salts of said polycarboxylic acids, and acyl halides of said polycarboxylic acids, is added to the mixture.

87. The fine powder of claim 69, wherein at least one additive selected from the group consisting of polymers, waxes, and greases, is added to the mixture.

88. The fine powder of claim 69, wherein at least one additive selected from the group consisting of polyolefins, paraffins, long chain fatty acid esters, and silicone rubbers, is added to the mixture.

89. The fine powder of claim 69, wherein at least one polymerization initiator is added to the mixture.

90. The fine powder of claim 69, wherein at least one basic material is added to the mixture.

91. The fine powder of claim 90. wherein said at least one basic material is selected from the group consisting of NaOH, KOH. Ca(OH)₂, Mg(OH)₂. water soluble sodium silicates, ammonia, and amines.

92. The fine powder of claim 69, wherein the mixture is ground.

93. The fine powder of claim 69, wherein the fine powder precipitates from said mixture.

94. The fine powder of claim 93, wherein said precipitation occurs in a stirred reactor.

95. The fine powder of claim 93, wherein said precipitation occurs in a flotation cell.

96. The fine powder of claim 69, wherein the fine powder includes at least one inorganic compound selected from the group consisting of Mg(OH)₂, Al(OH)₃, Ca(OH)₂. CaCO₃, hydrotalcites, and zeolites.

SUBSTTTUTE SHEET (RULE 26)