Synthetic meixnerite product and method

The present invention relates to a process for the preparation of mixed chemical hydroxides or layered double hydroxides. The present invention relates to a method for the production of synthetic me.ixRer.it for the benefit of the public.

In nature, mexnerite occurs in the Ybbsi (Persenberg, Lower Austria) fracture, which is found in the fracture. The tabular, colorless cleavage of the mexnerite in its crystalline state is perfectly main-state. In terms of the general structure of the natural mexnerite, it is a close relative of the hydrotaxis and the pyroaurl. Infrared cloth. compares well with the spectra of, coolant · kit and other synthetic double magnesium ·· aluminum hydroxides., neixnerite in other circles in other circles ·> * »> <» 'Χ «» φ * Φ Φ « Φ X

ΧΦ * &lt;«φ XX« Φ »kit-like materials, listed or classified in the broader family of 'bidro bowls. According to the latter definition, meixnerlt is a carbonate-free member of the bidrotalkif family, in which only hydroxylilones are present. Others consider mexnerite to be a fully hydroxylated, layered double hydroxide.

A. meimnorite, that is, hydrated magnesium aluminum bldroxide in many cases, is: kggAi₂ (OH) -5 g - 4H₂SHE_f other times Mg, &lt;Ai₂struck &lt;- 3S₂G or tkg- ^ Ai (OH; &amp; amp; 2H₂Let me describe it with O formula

Although the synthesis of meixn.er.it is a fairly new process, it seems that these various production methods are not generally fermented, and this is not the case. G, Ma sco .1 o et al. [kineralogioal Magazine (1.98-0. xuara.)) described a conventional method in which magnesium oxide obtained by decomposition of magnesium carbonate at 650 ° C for 6 hours was stirred with an oxide-gel in an oven thermostated at 80 ° G. According to the analysis results, the product thus obtained is some. and about 0.8 ~ 1.0% by weight of carbon

- contained di oxi.do.

Six years later, 1, Pauseh et al. Described a modification of the above process [Clay and Miller, Here, magnesium oxide annealed at 50 ° C with alumina gel (S.-AlgOrj), MgCl 2, zh-yu and distilled water, then the mixture was stirred at 100 kPa. pressure. 100 ~ 350 for 7 ~ 42 days^cThe results of Ifrared Spectroscopic analysis showed that the product contains some carbonate contamination, but at 5% Intensity compared to natural hydrotactic ** · * χ ♦> * «* *« ** ΧΦ * ♦ Ο XX »Χ * Φ X * *« * * *> · »« »* Λ * # ί *

Di, Di.motak.ls et al., Inorganie Chemistry, vol.

No. 13 (1990; new edition ··) in their series, the synthetic mexnerium bed was made> that one [kg ₃A1 (OH) g] (CO3} ₀.₅ ♦ 2HyD] was stirred at S.0 ° C to give a metal oxide solution and then^SheAt C, the bridge was closed in a carbon-free environment.

It is a primary object of the present invention to provide an improved process for the production of synthetic mexnerite. A further object of the present invention is a process for the synthesis of mexnerite and similar minerals from two powders. Yet another object of the present invention is to provide a substantially lower carbonate content and virtually free from other anion effluents. 1 dret a. 1 kit ·· s 2 E re g u r e d 1 11 G e tting a. The Taim is more. relates to a process for the production of synthetic mexnerite which is independent of the use of alumina gels. It is a further object of the present invention to provide an improved melxnerite product with transient alumina. and activated magnesium oxide other than. burned or overcalculated,

An advantageous alternative to this process is that the synthetic mexnerite can be obtained from very crude and readily available raw materials, thereby allowing the industrial production of melxnerite and similar materials. surpasses others such as magnesium carbonates, magnesium hydroxides and / or aluminum · hydroxide salts,

In accordance with the above objects and advantages, the present invention relates to an improved process for the production of .meixner.it. The procedure out of it

<img file="HUT75979A_D0001.tif" />

in the form of powdered magnesium hydroxide solution which is substantially carbonate free or is reacted in suspension with translucent alumina having a high specific surface area. In this reaction, a mexnerite-like region is formed, which can be removed from solution by filtration, centrifugation, vacuum dewatering or other known separation techniques. In a preferred embodiment, the specific surface area of ​​the alumina oxide thus combined with the activated magnesium oxide is about 100 m.²/ g or more. To form certain double hydroxides, the powdered starting materials to be mixed can be agglomerated before being contacted with water or steam. The same invention also encompasses an improved synthetic blend product obtained by the above method.

Further features, objects and advantages of the invention will become more apparent from the following detailed description of the preferred embodiments of the invention, reference will be made to the accompanying drawings, in which a method according to the invention is provided. , ja 1 á that she.

Transient alumina refers to al.um.ini-oxide having a large specific surface area in the form of powder or small particles. A preferred way of defining such alumina is to provide a specific surface area and a loss of luminosity (LG1). Thus, in particular, an aluminum oxide having a specific surface area of ​​about 100 µm / y as measured by the Brunauer-Ernmett-Taller (BST) method is considered to be of high specific surface area and thus suitable for the benefit of the present invention. Aluminum oxide with a BOT loss of about 1.5% or more is considered transient alumina at this level, whereas a typical δ-alumina is not. qualifies as such.

One particularly preferred species of transient alumina is referred to as re-hydrated alumina oxide · '. When in contact with a chair, they form strong hydroxy bonds, their reaction is strongly exothermic (heat-producing). Such alumina may have a particle size of from 0.01 to 200 µm, preferably from about 0.1 to 10 or 20 µm,

Certain alumina are more suitable than others for the purpose of the invention. Most suitable are alumina with a high specific gravity wall, which are prepared by rapid calcination of hydrated alumina at a temperature lower than that required for the oxymer bowl, i.e. for calcination. Such alumina oxocarbon gen l cl £ 1 year is determined to be amorphous according to the determination of 1 m, ie they have no microcrystalline structure.

In a more preferred embodiment, the trivalent oxide of the trivalent oxide to be mixed with the magnesium oxide is prepared by rapid dehydration of alumina trihiarate, usually by passing the anhydrate through a burning or lithium gas in about 3.5 seconds. The resulting alumina derivative is LÖT. from about 4 to about 12% by weight of BST with a specific surface area of ​​about 200 to about 300 ppm. / g. One typical and preferred material is the activated alumina powder commercially available from CB Seriem Aluminum Company of America (Alcoa). mark. Such powders are available in a variety of particle sizes.

The Alcoa CB labeled sled shows the average particle size of the product, for example, more than 50% of the particles in Alcoa bump powder have a size of 1 µm or larger. Alcoa CB-2

X &lt;l. &lt;«99» X

9 9 * 9 *

X 9 ·> ♦ ** 9

9: 5 * 9 »» 5 .9 9 * 9 9 9 * 5 9, more than 50 'of the particles have a particle size of 2 µm or more, and so do the Alcoa CP-5, CP-7 and CP -iQ topics,

As used herein, either magnesium oxide or magnesium oxide is a magnesium-activated product activated by mild combustion at temperatures between 450 and 90 ° C. The specific surface area is generally IC - 200, preferably approximately. 25 - 150m²/ g, HORSE. and from 1.0 to 6.0% by weight. Material A generally contains from 0.51 to 1.61% of carbon dioxide. Criteria distinguish this preferred material from activated or completely chelated activated magnesium oxide. Although it is. in the latter, melxneris may develop over a longer reaction time and under more intense reaction conditions, but it must be obtained in such conditions! significantly smaller than in the process of the invention. For example, commercially available magnesium carnonate is heated to expel carbon dioxide to form active magnesium oxide. Magnesium oxide can also be produced to produce exemplary or artificially produced magnesium oxide 360 It is heated to 95 [deg.] C. and basic magnesium carbonate is treated with lime magnesium chloride. We are heated. Various methods are known to those skilled in the art, and for example, magnesium powders of various particle sizes and / or species surfaces are available at

As used herein, carbonate contamination refers to the concentration of carbenate ion. the final product. This is sometimes given in carbon closed-litter k, which should be converted to the more pronounced actual carbonate content. such as calcium oxideφ ** φ * &lt;♦ »φ φ # * χ 5 ** · * φ * * φ Φ $

Φ X- Φ Χ * φ «» χ

Φ Φ ί Φ V * ** Φ ΦΦΧ φ Φ * / ΦΦ • -Ϊ glaze.

This mechanism can be summarized, for example, by the following reaction equation:

V y 'k._?o - 'Jvk' Mi _Kwherein t is from about 0.1 to about 1.0.

In order to increase the overall solubility of the fructose ai.u.mi.nium boxide starting material, the pH is preferably maintained at 11 or higher. Limiting the temperature of the contacting aqueous solution also advantageously affects yield. The reaction is preferably carried out at a temperature of 80 to 180 ° C. At such temperatures, it is generally possible to obtain fumes of between 85% and 90%. The reaction temperature is still preferably between 95 and 150 ° C,

The products of the present invention can be used for various purposes. The most important case is that it is contacted with carbonate or other anionic exchange agent to form a brothalkite. or hydrothalkite-like material.

The following examples are available at two temperatures; at atmospheric boiling point of 98 ° C} and 15 ° C. At atmospheric boiling point, significant transformation takes place within 2 hours, but an even greater degree of transformation was observed in the X-ray diffraction pattern._1A Aluminum double hydroxide was obtained by heating the slurry of magnesium oxide-aluminium oxide for 2 hours or more at -58 ° C, m.p._;... Jl £ UDA t ..... ..... AktryáÍ_;YJT t ^^ ^ ,,, aInitlgútumuud nézUsnopxlö alkaimazésa ...

AF; is he r S e 1. e n. ye fi c c supplies 11 M g (G 0₂} 4 (OH)>

K₂0 *> X »» Χ X Φ ·>

·> Ψ φ X Φ X

X «. Romag »képl -XX Χ-ΦΦ ~ g Bridge Magnetite for Magnesium Oxide Production for 2 hours 475^SHEWas heated to about C,

(a) Reaction at atmospheric boiling point:

A reactor was charged from the resulting magnesium oxide

52.5 g and 34.2 g of alninuric oxide activated on Alcoa ÜP-2, approximately 2 nm particle size. 'χ r. · - r and an additional 18.5 hours on this. we kept it at that value. Two hours after the reaction mixture reached 98 ° C, the slurry was sampled, filtered and the resulting solid was dried at 105 ° C. X-ray analysis showed that the solid thus obtained was largely mexnerite-like and a small amount of magnesium hydroxide was present. The suspension was stirred and heated for an additional 16 hours, then cooled and filtered.

The supernatant was dried overnight at 5 ° C, X-ray diffraction. analysis showed that the post-hybrids were composed mainly of mexnerite and that some residual magnesium hydroxide was present.

b) Reaction at 15 ° C

Another suspension of the above formulation was stirred at 60 ° C for 4 hours, then the temperature was raised to 55 ° C and the temperature was maintained at this temperature for an additional 13.5 hours. hours after the reaction temperature reached 150 ° C, it contained mexenent and a small amount of converted magnesium hydroxide. Two further samples of cooled reaction bundles of samples showed only the presence of a meixner-like substance.

&lt;"* Χ * ~ 9 -

X .... £ éhda U / ellerim; ....nagné ^ η, ΑΪηόΐΙΖίΙηΖΐη

About 53.5 g of magnesium oxide and 34.2 g of activated aluminium oxide were mixed in a Turbula powder blender for 2 min. The pore mixture was then formed into a pellet by a hydraulic press at a pressure of about 2270 kg (5000 lbs)>

(a) Reflection at atmospheric boiling point:

Of the pellets prepared in the font, lo db was placed in a beaker and filled with deionized water. The system was boiled at atmospheric pressure and heated for about 2 hours. Except for the turbulence of the boiling water, stirring was not used. One pellet was split into three, another into two, the rest remaining, though some appeared cracks perpendicular to the press. X-ray diffraction analysis showed that the pellets contained mexnerite-like compounds, a small amount of magnesium hydroxide and traces of magnesium oxide, b; Liquid preservative in water at 15 ° C

From the above pellets, a new db was placed in the Parr ankle and a little deionized water was added. The reactor was then sealed, about 1Sö⁰It was warmed to C and kept at a temperature of 2 hours within. After the reactor cooled, the pellets were removed and placed in a vacuum cabinet overnight.^SheIt was dried at C. X-ray diffraction analysis showed that pei.I.et contains a merxnerite-like compound and a small amount of boomite.

Example L ..... ..... ... n..Magaezlt sky grcUnrUt signal ,,, ^

A sample of minerals containing magnesite, dolomite and quartz was ground at 44 µm (325 mesh) and calcined at 700 ° C for 2 hours, resulting in a total weight loss of 46.5%. Analysis of the material thus obtained showed the presence of about 16.9 weight percent magnesium, about 5.66 weight percent silicon, about 1.75 weight percent silicon, and about 0.4 weight percent iron (the amount of magnesium, calcium, and silicon by atomic absorption, spectroscopy), the sulfur content as determined by bKCO analysis was found to be 46.2%,

750 ml deionized water, .34.2 g Alcoa C? ~ 2 alumina and 61.6 g of the above caidite magnesite. The resulting S2 suspension was placed in a? Autoclave ··· reactor and kept at 60 ° C for 4 hours with constant stirring.

(a) Recycling at atmospheric boiling point:

The suspension was refluxed for 2 hours at atmospheric pressure and the sample was spiked. The residue was filtered, dried at 110 ° C overnight and then sampled for analysis. According to X-ray diffraction analysis, the solid consisted of raxnerite-like materials and tricalcium-aluminum backing, and contained a large amount of quartz,

(b) Recycle at 150 ° C:

The reaction mixture was heated to <RTI ID = 0.0> 8S8 </RTI> and after 2 hours a sample was taken. At the end of the experiment, the reactor contents were filtered and the filtrate was sampled for analysis.

Both samples were dried at <RTI ID = 0.0> 1100 </RTI> overnight. X-ray diffraction analysis showed both solids

X ** ΦΛ * «χ«

Contains high levels of meixneric t-like substance, tricalcium aluminate, nysmm of quartz and trace amounts of mica.

For comparison, some mexnerite samples were delayed using alminium hydroxide as the starting material and magnesium oxide prepared as in Example 1 above, using a direct comparative chromatographic (Οηό ^^ώ~) -absorption test. (which serves to determine the relative amount of mexnerite-like substances present in the resulting product) the samples are not. they gave me great results like the ones we made with trane aged aluminum oxtd,

BOARD

Sample Aluminum Formation Cream Content Source Time (Hours) {·%) (Relative to Grass Control)

<td>THE</td><td>CP-2 A1₂SHE_?</td><td> 18,5</td><td>11, δ 4</td><td> [6,82)</td>

<td>B</td><td>Al (OH)₃</td><td> 21.73</td><td>7, SEE</td><td> 18,32]</td>

<td>C</td><td>Al (OH)₃</td><td> 22, .17</td><td> 7,43</td><td> (8.52;</td>

In the foregoing, the presently preferred embodiments are embodied, but tslákkao are m - '&lt;e \ el' ypoutok? Italm_THE can be implemented in other ways within koo.