DE1467063A1 - Selectively absorbable SiO2-containing material and process for its production - Google Patents

Description

Selectively absorbent SiO2-containing material and process its production The present invention relates to new SiO2-containing Substances in particle form that are particularly characteristic both chemically and physically and have special characteristics, but especially an extraordinary one high chemical reactivity and a unique selective absorption capacity for substances of a certain molecular size. The subject of the invention is also a process for the manufacture of these substances.

Finely distributed SiQ2-containing materials of the most varied types are already known. Some of them have significant uses as inorganic ones Fillers, suspension agents, extenders or pigments found: (1) natural, crystalline Silicates or clays, such as. B.

Kaolin; (2) finely powdered quartz, which is considered to be crystalline silicon-containing Substance of low chemical reactivity consists of SiO, tetrahedra which are linked spirally to form hexagonal prisms; (3) precipitated silica Compounds or hydrated silica with SiO4 tetrahedra and OH groups that are confused are bound to tiny spherical microcrystalline amorphous masses that like caking; (4) fumed or vaporized silica that secretedex represent anhydrous, spherical colloidal masses and mainly made of siloxan O-Si) groups exist; and finally (5) very finely divided downed Sodium-aluminum. msilicates, as they are e.g. Bo in U.S. Patent No. 2,739,073 are.

It has long been known that more or less contaminated silicon-containing Substances are obtained as residues in reaction sludge if particulate, water-containing aluminum silicates, such as kaolin or similar clays, whether they are aqueous States or after calcination, in an aqueous medium, for the purpose of extraction of aluminum from the silicates, brought into reaction with strong mineral acids like the @ e.g. is the case in aluminum extraction, where clay is mixed with sulfuric acid is allowed to react.

Although already different, both manufacturing and processing proposals were made with the aim of winning these backlogs in such a way that they would be economical are usable, this silicon-containing material, the so-called silica residue, quite generally separated from the reaction sludge and - for lack of it - more economical Recyclability-discarded. However, as disclosed in US * Patent Mr. 2,848,346, can be an aluminum solution obtained from kaolin and still containing silica residues can still be used economically if you react them with sodium silicate leaves and so a precipitated sodium aluminum silicate pigment with increased SiO2 content manufactures.

According to the present invention it has now been found that extraordinary Manufacture reactive and sorptive silica materials in a particle form let the particles, in contrast to known silicon-containing substances, are quite distinctly paracrystalline and a distinctly hexagonal, phylloidal one or have a wafer-like structure. Among other things, these particles stand out by a very large width: thickness ratio, i.e. by the fact that they are very are thin, and by an extraordinarily large porosity as well as by a unique chemical reactivity and selective sorption power. Composition, Shape and properties make these new fabrics very valuable and for many Purposes.

The silica materials according to the invention exist as the analysis shows, essentially of silica and bound water as well as small additions other mineral oxides. They contain at least 75%, preferably 83 and more% (wt.) SiOp, at least 5% bound or linked H20 and less than 15%, preferably less than 10% other oxides.

Structurally, the Si, oxygen, and hydrogen atoms are in laminar Arrangement networked with each other, whereby the individual particles expressed their own get a hexagonal, phalloidal shape, and also a very large surface, which is largely porous. Reactive silanol groups form on the surfaces (SiOH) with a concentration of more than 20 micromoles per square meter of the panels Particle area.

The particles of the new material have very different viewing dimensions in a measuring range of approx. 0.1 to approx. 5 microns.

The prevailing particle width is generally between o, 5 and 2 microns. The thickness of the particles is far less, and is average only. 003 to 2o microns 3o to 2oo Angstrom units). For example, how to use the stereo optical and see electron microscopic silhouette can, the predominant thickness is only. oo4 to eoo8 microns. The particles possess thus an extraordinarily large width: thickness ratio characteristic of them on the order of 254: '!.

The BET area of the material, determined according to the well-known BRUNAUER, EMMETT and TELLER method ("BET Multikayer Absorption Theory", Journal of the American Chemical Society, Vol. 60 (1938), p. 309) shows values between 300 to 500 m2 / g, and the most valuable material segar values between 350 to 470 m2 / g. the In contrast, finely divided, reclaimed heolines have BET area values of only approx. 15 m2 / g, while, comparatively, precipitated silica pigments have a BET area of 70 to 100 m2 / g.

The materials according to the invention also have, in their individual particles, based on the total area, a measurable, more than 60%, for particularly valuable items Material, a porous area of 85 to 92% and more. This is known from Materials not to be found. Jumps or gaps in the atomic network should be allowed justify this porosity. In addition, 50 to 80% of the surface consists of pores, that are less than 2o Angatrom units (.002 microns). The determination is based on recognized, analytical test methods (A.VOET, "Determination of Pore Size Distribution ", Rubber World, 'Tol. 139 (1958), pp. 63,232). The pores are parallel arranged to the three crystal axes of the particles.

These pores give the material its unique, selective absorption capacity, whereby substances with an Angatrom and below are very easily absorbed, substance but hardly with larger molecules.

The extraordinarily high chemical reactivity of the new Silica materials is arguably best manifested by the speed of sight and the extent of their reaction with bases in dilute aqueous solutions it e.g. at a concentration of 39.6 g SiO2 / liter in a 1-N solution of NaOH (31.5 g NaO2 / liter) at 50 ° C for reaction, generally at least 80% dissolve SiO2 within 30 minutes. Material with a SiO2 content of more than 83% is even dissolved with 90 - 97% of the SiO2 content in the course of 30 minutes.

This uberuas high reactivity of the materials is the most pronounced attributable to the morphological structure of the silicon-containing particles. The particles are paracrystalline in that they are in the X-ray diffraction pattern of a broad amorphous band with no discernible crystal structure demonstrate. The particles seem to be formed from tetrahedral SiO4 groups, dite are crosslinked in hexahedral layers, with four 0 atoms inside each lying Si atom, and three 0 atoms have a peripheral Si atom in common. The fourth Valences of the peripheral Si atoms are saturated by hydroxyl radicals, so that these Atoms form parts of perlphCrer Silanol (SiOH) groups.

Calculations made on the basis of analytical results show that the concentration of silanol in the particles is more than 20 micromoles per square meter flat surface, considering the uses of the new Silica Staffe, you will find that in some cases, albeit more complex, materials already known and mentioned can be used in other cases but not. So the new materials are because of their high reactivity z. B. very useful in the production of more valuable silicates, where you can directly with various bases, including alkali metal oxides, calcium, magnesium and others alkaline brd metal oxides, other basic metal oxides such as zinc and lead oxides, lets react.

Their chemical and surface properties make them special Mass suitable as an absorbent for moisture, zoo for the preparation of Salt ; but also for the sorption of various gases, vapors, Odors and liquids and as a carrier for chemicals, such as rubber accelerators, or antioxidants, insecticides, fungicides and the like. They are further useful than Fillers, pigments or extenders in various compositions, including rubber, plastics and other polymeric substances, ceramics, adhesives, Paints, inks, paper, paper coatings, glass compositions and the like.

Quite surprisingly, it was found that the new material, in fine distributed solid state, direct and quite active, with finely distributed barium, Calcium, zinc, lead or magnesium oxide reacts, with the corresponding Form metal silicates in particle form that are free of soluble salts. The manufacturing cost are far lower than with comparable, previously known Metallailikaten. The solid state reaction can be carried out very simply by only the solid components are suspended in the aqueous medium and the suspension, z. B. heated to 9o-loo ° C. The temperatures can also be lower at the same time longer reaction time, or higher, with a simultaneous faster reaction, aein. the Particles of the metal silicates obtained in this way are extremely ports and have there are other significant characteristics, such as selectivity and extremely high latitude : Thickness ratio adopted from the Si material. When heating the material a violent exothermic reaction occurs with magnesium oxide in an aqueous medium. After 1 to 1 1/2 hours of heating at 90 ° C, the yield is on average consists of finely divided, absolutely crystalline, porous magnesium silicate and whose BET surface values are very high, for example at about 450 to 600 m2 / g.

It was also found there. the new material with primary and secondary alcohols. such as butanol, decanol or octadecanol, in a pressure reactor at temperatures of, for example, 200 to 240 ° C. react or condense leaves. Valuable esterified silicas, so-called "Estereils", are formed have retained the sheet-like particle structure of the starting material, although the 8ilanol groups mainly, but at least 90%, with the esterifying agent have reacted.

Furthermore, it was found that without difficulty, by simply Digestion of the material with sodium aluminate in an aqueous medium and at temperatures from 90 to 100 C. a sodium aluminum silicate can be produced, the particles of which have an extremely cubic shape and also have a correct crystal structure, interspersed with pores of a certain size9 are also the materials with liquid alkali silicates. mixed and then heated so they react directly and immediately. The product obtained is silicates with an increased SiO2 content, for example liquid sodium silicates with a Na2O # SiO2 ratio of 1: 4 and above, and for solid sodium silicates from 1 s 5.

This absorption of the new substances makes them very valuable for Paper and boxboard adhesives and silicate coating agents, such as Bie for roof sanding, Asbeetechindeln and similar products are used.

In the context of the present invention it was also found that the new, reactive, selectively sorptive silica material under atomic spheres Pressure conditions can be obtained by direct acid decomposition stormy reaction and one the same. early final treatment of a finely divided, particulate metal silicate anhydride, suspended in an aqueous medium, provided the used anhyz by high heat treatment or calcining of a hydrous metal silicate of fine particle form was obtained. For this process requires a strong mineral acid, e.g. Sulfuric acid found in the aqueous suspension of anhydrous metal silicate has a stormy exotherm Reaction triggers. Likewise cold or sulphate or hydrogen chloride gas be used.

The silica materials can preferably be made of finely divided clay, such as kaolin. Kaolin is an asaerhaltigesAluminiomeilikat.Aufdieae in the Satur It is wise to obtain not only much more valuable, new ones from a comparatively cheap raw material Silicas but also an aluminum salt solution that can be used on its own or as an output is valuable for the production of other substances, such as aluminum, if sulfuric acid is used or when nitric acid is used and recovered from solution or aluminum compounds in the production of aluminum or other aluminum compounds.

In a powerful process for creating the new fabric a very fine metal silicate, e.g. finely divided, water-containing aluminum silicate, like @aolinton with particles that have been brought to practically the size of an element, initially through the sufficientit.oaSilike.rlligwsarfreis.umachen, i,. r. :. ' ; . v, ui '? ,,; ^ a,. ° axr $ zEht durat heating to a temperature of 500 to 925 ° C and calcined for a period that is sufficient to make the Stlika @ @ öllig water-free. The fine-crowned anhydride obtained was then pensed out in a watery medium @@@ at atmospheric pressure with a stern mineral acid, such as @@ sulfuric acid, in one for one bracht, DiesP'.k.'c-i.cymiesu.daSsiaunterXontrlle} p; t'h. '. ti 'n? elLi a! :. > -1. , '. '.'a ""'. ::. 1P r a:., 3 ts! Y3 '38! '' R ^ the Mixture dissolved for a few hours at a temperature of 9o to 100 ° C, eo long to more than 80% of the metal oxide content of the particles is extracted and the The solid particles obtained have reached the desired high SiO2 content pending particle residues are then separated from the reaction liquid, washed to remove soluble components, and finally dried e The most favorable temperature for calcination is between about 700 and 900 ° C. When calcining in portions in a muffle furnace, for. B. is the cheapest Heating time at least 2 hours at 700 ° C. This time is increased with lower ones Temperatures and shortens accordingly at higher temperatures.

The heating can also be carried out continuously in a rotary oven, a vertical oven or a calcining furnace with a fluidized bed. In each of these ovens you can have one Temperature of 800 ° C. to be worked. This is achieved with a shorter heating period the same successes as with batch caiciner and the same Temperature.

The material treated in this way is an anhydrous aluminum part, which still has the appearance of kaolin particle when viewed under the electron microscope considered. The material is neither particularly reactive with a 1-N solution NaOH, still somehow usable porous in the nitrogen absorption test. The material is now broken or otherwise crushed and then completely suspended in water; The acid is then added to the suapersion and with the suspended particles brought to reaction.

The reaction takes place at atmospheric pressure and a concentration which is sufficient to initiate a stormy exothermic reaction in the mixture.

The necessary amount of acid is 90% of the stoohiometric excess Amount based on the Al content of the silicate. In the interests of an economic Utilization of the liquid medium and the recovery of the remaining aluminum The SEurenege should correspond to 95 to 100% of the stoichiometric amount.

Kan can use larger amounts of acid, the quality of the silica material however, this does not improve it and amounts of 120% can even be disadvantageous affect the properties of the product. When using sulfuric acid stubborn amounts of free acid remain in the aluminum sulfate obtained as a by-product.

When the acidic reaction mixture is produced, that of the suspension stands the amount of water serving the Sillkatpartikel in relation to the amount and concentration the added acid. An acid concentration of Do-50% in the aqueous should preferably be Medium present. In certain cases it is possible to work with a lower acid concentration-2o % and below-this comes at the expense of longer development time, however, it takes longer until the stormy exothermic reaction increases.

The acid is preferably added in a highly concentrated form, so that one can use the heat of solution. With concentrated sulfuric acid is sufficient the heat of solution to increase the temperature of the reaction mixture, e.g. from 20 to 30 ° C, 75 to 85 ° C. to raise.

The violent exotherm occurs 2 to 3 minutes after the addition of the acid Reaction starts spontaneously, heating from outside is not necessary, the initial temperatures suddenly rise to over 100 ° C with the addition of the acid. at.

The exothermic reaction described and the smoke that accompanies it The development of heat within the whole reaction mixture causes a strong one at the same time Boiling and frothing, the mixture expands, the liquid level in the reactor increases To keep the reaction in check, a very tall reactor is necessary.

In the case of large-scale production, however, this measure is not sufficient either, it can. a very high reaction vessel alone does not control the reaction be held, the mixture foams too much.

The reaction can, however, be kept under control in this way, dad then let the Gemiach boil stormily until the initial volume is reached dae has expanded 3 - 5 times, and then the mixture has excess heat which lasts In this way, the cooking does not get out of control.

The excessive foam of the mixture can be contained in that relatively cold water is added to the stormy reaction. The water becomes sprayed onto the turbulent surface of the mixture using spray nozzles The addition of water not only absorbs excess heat but also ensures that that the liquid medium remains sufficiently watery despite the constant loss of water. if the steam created by the boiling of the mixture in the icht:: xr: in the Rta. kf. uL ic; aris. ^ we ,, r g. c,: ztl ez. e ..., but must not be like that be great that the stormy reaction is prevented or slowed down. One begins so after the @; . he Feaan gtzt n. xd. i. ca: --i * ta. dd wc, u : r zti. t. n tgn8en, la: di c tz '. :. c. e x u = r3. 3. Whole device @ by no means but may the crowd calm down x. n, iaee eree. utun: x2 a nc. . : ale'aa:. vni i; ' : '. 1 e:, r. n.

The reaction has been allowed to run its course.

The reaction mixture is stirred with constant vigorous stirring at a Temperature of over 90 ° C and in any case below -1o5 ° C unlocked for a period that is sufficient to completely remove the aluminum from the silicate particles. The digestion is preferably carried out at a temperature between 94 and 100 ° C. The duration is 2 to 6 hours, whereby the temperature is increased by adding external heat is held. This is done by direct introduction of steam or by heating of the reactor in any way, e.g. B. by a steam jacket or by gas firing or by an electric heating jacket.

During the treatment, the aqueous medium is at an acid concentration held, which is calculated-incl. free and bound acid-based on the added quantity of SQur and is below 50%, preferably between 2o and 4o%. One Acid concentration of approximately 30% is particularly advantageous for an economical one Recovery of the aluminum from the reaction liquid present at the end. Concentration and temperature during the digestion can be adjusted by adding an appropriate additive of cold water to be adjusted to the reaction mixture as soon as the exothermic Reaction the mass no longer expands and falls to normal. It should, however Avoid diluting the acid concentration below 15% a sinks. Indeed, this would lengthen the treatment time to such an extent that it was uneconomical will.

It is of particular importance that the acid concentration during the digestion below 50%, and the temperature is below 1o5 0. Higher temperatures and higher Acid concentrations have a detrimental effect on the silica material, which is great Surface and high porosity of the material is concerned.

It also makes the silica material with harmful and disadvantageous Amounts of acid permeated by the usual filtration, washing and neutralization cannot be removed ...

The quality and usability of the final product will greatly increase influenced not only by the course of the acidic reaction but also by how the calcination proceeded.

A product with, for example, 67.5% SiO2 that has been extracted, by calcining for 2 hours at 55o ° C, then for 4 hours at 94 ° C first exothermic, then in an aqueous suspension with one of the A1203 content of the silicate had digested the corresponding amount of H2S04, showed considerably poorer quality, in terms of reactivity, surface area and porosity, ale z. B.

Products that were manufactured in the same way, only with dom difference that silicate anhydrides were used for two hours Temperatures of 700 ° C, 800 ° C and 900 ° C. had been calcined. Comparative figures are brewed in Table I. As can be seen from the same table below, According to the invention, however, more valuable material can also be obtained if one in in the same way starts from anhydrous silicates, which at 550 ° C. but significant had been calcined for a longer period of time.

Bingo characteristic bigenso adhesions of the silica material according to the invention can be seen from the attached electron micrographs.

Fig. 1 shows, somewhat reduced, a typical group of particles at 14. Ooo times magnification.

2 shows the same material at 92 in a micrograph. ooo times magnification.

Pig is particularly good at. 2 rule that the elementary particles of the material have a decidedly hexagonal shape when viewed from above and so thin and are delicate in that they are almost transparent to the electrons. Although the heragonal Outlines of kaolin particles remember, they are different clearly distinguished from these by their extremely thin wafer appearance.

The materials and their manufacture are discussed in the following Examples and test results are described in more detail.

Example A 1. 000 g of a kaolin clay that has been refined in this way was that 55-60% of its particles were smaller than 2 microns and only 20-25% coarser than 5 micron goods (air-floated soft clay mined and refined at Langley, South Carolina) were heated for 24 hours at 55o ° C, then cooled and finally thoroughly in 1505 g of water to which 2.5 g of tetrasodium pyrophosphate were added as a dispersant The kaolin used had a BET surface area of 14.9 m2 / g and had the following composition: Al2O3 39.25% 8iO2 45.12% Fe2O3 0.71% TiO2 o. 89% CaO o. 49% MgO 0.14% N O (bound) 14.13% of the dispersed, heat-treated Kaolin anhydride was concentrated by adding 119o g. Sulfuric acid (93, 19%) with a spec.

Acidified weight of 10835. The acid was added quickly and while vigorously stirring the slurry. Stirring was also continued during the reaction. The amount of acid corresponded to 100% of the stoichiometric amount of the A1203 content dee used tones.

This resulted in an acid concentration of 40.8% in the aqueous medium.

Immediately after the addition of the acid, which in itself already becomes a considerable one Increased temperature of the pulp, a stormy exothermic reaction occurred, which after 2 minutes already a strong boiling and foaming of the mass, as well as a Reaction temperature of 1o5 ° C resulted. The mass was left in the reactor Boil for a long time until the volume has multiplied. Then there was another Foaming is curbed by tapping water at intervals and amounts of 100-20o g added.

After the stormy, exothermic reaction has ended and the Volume to almost normal, water was added again, whereupon the temperature rose 94 ° C and the acid concentration to 3o% - calculated on the addition of acid - sank. All in all 100 g of water were needed to contain the foaming and the final temperature as well as adjust concentration.

The acid reaction was terminated or brought to an end by the Mud held at 94 ° C for 4 hours. After processing was completed, the slurry became slurry chilled, diluted with water, and then filtered; the filter cake was made in order to Removal of free acid and aluminum sulfate, washed with water; the washed out Solid components were at 105 ° C. dried and then crushed in a powder mill.

The silica material obtained was analyzed and checked for various Kind of examined. For the set of results, see the last row of Table I.

Example B The same procedure was used with regard to dispersion and SFure reaction in example A only heat-treated aluminum silicate those of kaolin were used that had been calcined at 550 ° C for 2 and 8 hours instead of 24 hours. The two end products produced values in the first and penultimate rows Table I are listed.

When using the silicate material, which is only 2 hours at 55o ° C. had been calcined, no boiling of the acidified slurry occurred a. The measured maximum temperature. was 96 ° C and the slurry took 6 minutes until it reached this temperature level.

When using the silicate material that is kept at 55o ° C for 8 hours. had been calcined, boiling and foaming occurred, reaching after 6 minutes the pulp has a measured temperature of 1o5 ° C. At this point it was started curb foaming.

Example C Dispersion and acid reaction was carried out as in Example A, with the only difference that heat-treated aluminum silicate was used, that came from kaolin, that was 2 hours at 700 ° C, 800 ° C and 900 ° C, instead of 24 hours 550 ° 0 had been calcined.

The silica material obtained gave values as they are in the 2nd, 3rd and 4th row of Table I are listed.

When using the anhydrous silicate with a calcination 700 ° 0 a stormy exothermic reaction occurred in the acidified slurry and in 4 minutes a state occurred which made it necessary to keep the SchCumen under control bring to.

The measured temperature at this point was 105 C.

In the pollen, where silicates were used, resulting from a calcination at 800 ° C or 900 ° C. an extraordinarily stormy exotherm occurred A reaction that was so strong that the measured value in both pollen within 1 minute Temperature of the sludge to 111 ° or. 113 ° C. rose, and every further minute by 65 continued to rise up to 70 ° C. Foaming had to be curbed immediately.

Other investigations made have shown that one according to the invention Silica material is not obtained if calcination temperatures are below 5oo ° C and above 925 ° E. Such a material can be made by using hydrochloric acid or Nitric acid, used instead of sulfuric acid; but sulfuric acid is generally preferred because it is cheaper, more practical and more effective. Phosphoric acid in any case iat unsuitable as it only produces a slight exothermic reaction with the silicate, permanent phosphate residues and harmful acids are formed in the end product. Such an end product has neither the reactivity nor the porosity of the Silica material made according to the invention.

Natural hydrous aluminum silicates can be used in the production process be used, einohl. of the various types commercially available Kaolins with particles smaller than 10 microns in diameter.

T a b e 1 1 e I Calcination 2 hours longer at 550 ° C Chemical analyzes 550 ° C 700 ° C 800 ° C 900 ° C 8 hrs. 24 hrs.

% SiO2 67. 5 84. 4 86. 8 88. 6 77 85.3% H2O bound (loss at 900 ° C from dry weight at 105 ° C) 10.65 8.30 7.47 5.50 9.75 8.18% metal oxides 21. 85 7. 3o 5. 73 5.90 13.24 6.52 Reactivity% SiO2 content soluble in 30 min. in 1-N-NaOH at 50 ° C sample 39.6 g SiO2 / liter 67.4 96.0 95.1 96.0 81.5 93.5 Silanol concentration Micromoles / m2 flat surface 42 129 148 148 74. o 135 acid-mol. equ./100 g. oo5. oo4. oo3. 003. 004.005 Total BET Surface Area, m2 / g 200 398 457 457 313 418 flat m2 / g 64 36 41 41 56 38 pore area m2 / g 136 362 416 416 257 380% of the surface in pores 68 91 91 91 82 91% volume in pores 15 36 4o 55 26.5 39 Oil absorption ml./100 g 62 72 66 76 63 70% water absorption at 72 R.H. 7 13.7 16.7 18 12. 3 14. 2 Water tolerance for salt 0.50. 59, 64, 72, 54, 58 the The values listed in the table for the silanol concentrations were determined according to ZEREWITINOFF REAGENT METIIOD determined for the determination of active hydrogen. the Technique of this method has been described in: SIGGIA, "Quantitative Organic Analysis Via Functuonal Groups "(Wiley & Sons), page 41, and GUENTHER," Determination of Silanol with Grignard Reagent ", ANALYTICAL CHEMISTRY, Vol. 3, No. 6 (JUNE 1958), Page 1118.

The numerical values given for the water tolerance give the number the milliliter is distilled. Water, that of loo g table salt with 1 wt.% Refining agent be tolerated until the salt in its container begins to clog The water is added by means of a burette at intervals and in an amount of 2-3 drops and the container is shaken for 1-2 minutes after each addition. Not refined Table salt usually has a water tolerance between o, o6 and o.18.

"Kaolin" and "kaolin clay" are understood to mean clays that are in the natural Raw state as the main component one or more of the naturally occurring hydrous Contain aluminum silicates, such as. B. kaolinite or halloysite, their composition can be represented with the following formula: Al203. 2 SiO 2 nH 2 O, (n = 2). the naturally occurring water-containing aluminum silicates or clays, which in the sense of the invention are useful generally contain SiO2 and Al2O3 in weight ratio approx. 1. o and approx. 1, 5

Claims (27)

P a t e n t a n s p r u c h e: 1. Reactive, selectively sorptive Silica material consisting essentially of individual, hexagonal-phylloidal particles which is based on weight analysis in the dry state at 1o5 ° C. 75-92% SiO2, at least Contain 5% H20 and less than 15% other oxides, characterized in that the particles have a characteristic thickness of approximately. oo3 to. own o2o microns, their facial dimensions are between 0.1 and 5 microns, their BET area values 300 to 500 m2 / g and at least 60% of the area of the particles being porous is. 2. Material according to claim 1, dad. gek. that the pores in the main have a diameter of less than a few hundred microns. 3e material according to claim 1, dad. gek., that at least So% of the SiO2 content dissolve in an aqueous 1 N NaOH solution within 30 minutes if the particles at 5o ° 0. and a concentration of 39.6 g SiO2 / liter of solution reacted will. 4. Reactive, selectively sorptive silica material that is essentially is composed of individual, hexagonal, phylloidal particles that are due to Weight analysis in the dry state at 105 ° C., 75-92% SiO2, at least 5% H20 and contain less than 15% other oxides, Claims (continued) due to the fact that the laminar crosslinked silanol (SiOH) groups of the particles are in a concentration of more than 20 micromoles per m2 flat BET surface are that the particles have facial dimensions, the measured values of which are mainly between 0.1 and 5 microns, that the characteristic width: thickness ratio the particle is 25o: 1 and the BET area number is between 300 and 500 m / g, The surface consists predominantly of pores, the diameter of which is smaller al9 oO02 microns. 5. Reactive, selectively sorptive silica material that is essentially consists of individual, hexagonal, phylloidal particles, which, based on weight analysis in the dry state at 05 ° C., 83-92%, 5-10 H2O and not more than 10% other oxides contain, in that the BE areas of the particles are between 35o and 47o m2 / g and at least 85% of this pluche is porous. 6. Material according to claim 5, dad. gek., that the particles per loo g less contain all o1 moles of acid. 7. Material according to claim 5, dad. gek., da8 over 90% of the SiO2 content dissolve in an aqueous 1 N NaOH solution within 30 minutes if the Particles at 5o ° C. and a concentration of 39.6 g SiO2 / liter (equivalent) be made to react. Claims (continued) 8. Material according to claim 1, dad. gek. that an anhydride is used. 9. Reactive, selectively sorptive silica. Material, dad. marked, that it consists essentially of individual, hexagonal, phylloidal particles, the facial dimensions between 0.1 and 5 microns, a thickness of approx. oo3 to o2o Micron and form tetrahedral SiO4 groups that are laminar to one another are cross-linked, the inner Si atoms being four oxygen atoms, and the peripheral Si atoms have three oxygen atoms in common and carry hydroxyl radicals, which in turn form peripheral silanol (SiOH) groups, and in addition, the particle analysis Weight% based on dry material (1o5 ° C) -75 to 92% SiO2, at least 5% H20 and contain less than 15% other oxides, their BET area is 3oo to 5oo m2 / g, at least 60% of this area is made up of pores, and the silanol concentration is over 20 micromoles / m2 the flat surface. 10. Reactive, selectively sorptive silica material, thereby characterized in that it consists essentially of individual, hexagonal, pphylloidalen, paracrystalline particles consists or is formed from tetratedric SiO4 groups, which are interlinked in layers, whereby the inner Si atoms are four O2 atoms, and the peripheral Si atoms have three Op atoms in common and peripheral silanol (SiOH) groups carry forming hydroxy residues, let the particle face dimensions between o. 1 and 5 microns - dry at 105 ° C. - from 83 - 92% SiO2,5-10% H2O and not more than 10% of other oxides, and their BET area between 350-470 m2 / g, with at least 85% of the F: '; hf "n-Prorf; n'.t't ;, Claims (Continuation) 11. Material according to claim lo. dad. gek. that the vast majority the pores have a diameter smaller than. oo2 microns. 12. Material according to claim 10, dad. gek. that over 90% of the SiO2 content are soluble in an aqueous 1 N NaOH solution within 30 minutes, if they in this at 5o ° C. and a concentration equivalent based on 39.6 g SiO2 / Liters of solution are reacted. 130 Process for the production of a highly reactive, sorptive, particulate silica material, dad. gek. that in an aqueous liquid finely particulate anhydrous aluminum silicate which, through heat treatment, contributes 500 ° to 925 ° C was obtained from fine water-containing aluminum silicate, suspended It becomes clear that this suspension is a strong mineral acid, the anion of which is only a soluble one Forms salt with aluminum, in an over-. Schüssigen amount of 9o% -related to the stoichiometric amount of the Al content of the silicate and a concentration that sufficient to cause a violent exothermic reaction, it is added that one this suspension (acidified) can be brought to the boil, but the one that occurs with the heat of the reaction Curbs foam formation that, after the reaction, the reaction mass is over 90 ° C and for a time that is sufficient that more than 80% of the metal oxide content the particle is withdrawn, treated further, and finally the reaction liquid separates, the solid components washes and dries. @ Claims (Continuation) 14. The method of claim 13, dad. gek. that the anhydrous used Silicate was obtained by heating finely divided kaolin, with a particle diameter smaller than 10 microns, at temperatures between 500 ° C and 925 ° C and for a duration, the at least one heating of the kaolin for 2 hours at 7oo ° C. is equivalent to. 15. The method of claim 13, dad. gek. that the anhydrous silicate was obtained from finely divided kaolin, the Binzel particles of which are smaller than 10 microns and that has been subjected to a heat treatment of 700-9oo ° C, 16. Procedure according to claim 13, dad. gek. that sulfuric acid was used. 17. The method of claim 13, dad. gek. that the added acid was approximately equivalent in amount to the Al content of the suspended anhydride. 18. The method of claim 13, dad. gek., that the addition of acid in in such a way that an acid concentration of 30-5o% occurred. 19. The method of claim 13, dad. gek. that the acid in a Concentration was added that the suspension warmed to a temperature which is sufficient due to the heat of solution the stormy Bxothermal reaction in To put in gear. 20. Verfahron according to claim 13, dad. gek. that you get the acidified Let the suspension boil to a multiple of its initial volume and then the foaming by extracting the excess exothermic heat of reaction under control. Claims (continued) 21. The method according to claim 2o, dad-k., that one takes away the heat by proportionately to the violently reacting mass cold water added. 22. The method according to claim 21, dad. gek. that the water on the Surface of the reaction mass, and added in single doses that the stormy Do not stall the reaction. 23. The method according to claim 13, dad. gek. that the explanation at a temperature between 9o ° and 100 ° C takes place, and the acid concentration of the Liquid the reaction mass is below 5o%. (calculated on the amount of acid added). 24. The method of claim 23, dad. gek., that temperature and concentration during the digestion is adjusted by adding cold water as soon the stormy exothermic reaction has calmed down. 25. The method of claim 13, dad. gek. that the explanation at a temperature of 94-1oo ° C. is carried out and for a period of 2-6 hours, the acid concentration being between 2o and 4o%. (Betechnet as above). 26. Process for making a highly reactive, selective sorptive, particulate silicate material, dad. gek. that finely divided, particulate, anhydrous Aluminum silicate is completely suspended in water, the silicate being in the way had been produced that one finely powdered kaolin, whose tertikol in the Nauptea. which had a smaller diameter ale lo tikron, at temperatures of 700 - 900 ° C low processed, Claims (continued) -still Claim 26-further dad. gek. That the slurry is stirred vigorously, that the Concentrated sulfuric acid is added to the suspension in an amount which is approximately the stoichiometric of the aluminum content of the dispersed silicate corresponds to the fact that the added amounts of water and acid in the liquid medium have an acid concentration create from 30 - 50% so that the slurry by the heat of solution of the acid heated and the strong exothermic reaction is set in motion, whereupon it in the reactor boils violently that after foaming the sludge-to 3 to 5 times the Initial volume - relatively cold water is distributed on the surface, and in quantities that would prevent further foaming, the stormy reaction but do not interrupt, whereby the addition of water is repeated depending on the foam, that the resilience after the stormy exothermic reaction has subsided, cold water is added, whereby the temperature is lowered to 94-100 ° and the acid concentration is lowered to 2o to 4o%, that the Aufschlammung eodern For 2 to 6 hours at ej-nor temperature tone 94-1oo ° 0. what is sufficient is kept Enrich the SiO2 content of the suspended particles to 83-92%, and finally dad. gek., dß abachliesaend the reaction liquid is separated and then the Solid components are washed and dried. Claims (continued) 27. The method of claim 26, dad. gek. that the acid concentration after lowering is about 3o% that it enables the proportion of aluminum sulfate in the reaction liquid without difficulty can be recovered.