SI7811639A8 - Process for treating hides - Google Patents

Description

The process of making leather

FIELD OF THE INVENTION

The field of the invention is a process for making leather using linoleum water-insoluble alkali aluminum silicates.

State of the art and technical problem

The most important part in making leather is the partial or complete replacement of the auxiliaries that put a heavy strain on the wastewater of the factories. This is particularly the case for the degreasing and dressing of bare skins as well as for the tanning of furskins and leather. In addition, other auxiliaries such as dissolving and degreasing agents, surfactants, electrolytes, phosphates, neutralizers, etc. are used in addition to the machinery.

The invention * is intended to reduce the use of chemicals and the water load at. leather production. To this end, certain alkali aluminum silicates are used according to the invention, which can partially or completely replace the commonly used excipients and which lead to a significant improvement in the wastewater status due to their ecological integrity.

The use of alkali-aluminum silicates has proved particularly useful in the following processes:

A. Degreasing and coating of bare skin

Nowadays, much used warty bare skin as a starting material for the manufacture of leather is pretreated with salt and acid and thus preserved. The pH of the material in this state is less than

2.

In the case of pre-tanning treatment, care must be taken to prevent damage to the skin structure by swelling. This is generally the case with concentrated saline solutions (6 '- 8 ° / Be). For the degreasing, anionic or non-ionic surfactants and possibly solvents are added to the mixture depending on the type of tanning.

Since the machining effect of polyphosphates is known, polyphosphate as hexametaphosphate has been added to soften and degrease the skin material. Their weak mechanical effect prevents swelling.

The tanning effect itself is not so pronounced that the character of the leather at the lemm stage of leather making is already determined.

The use of alkali aluminum silicates in the degreasing and coating of warty bare skin leads in particular to the following advantages:

1. Reduction of phosphates reduces the risk of eutrophication of water caused by wastewater containing phosphates.

2. Use solvents to degrease warty bare skin can be partially or completely waived.

3. Alka 1aluminium silicates exhibit considerable acid binding capacity and thus act in the removal of warts.

• Ί. The formation of annoyingly colored, chromophosphate complexes in the subsequent chrome tanning known in the use of polyphosphate .....

tov.

B. Tanning of furskins and leather

By far the most important type of tanning is chrome tanning. Based on acidocomplex formation and agglomeration of basic chromium salts with carboxylic groups of collagen.

In addition, other basic metal salts, such as iron, aluminum, zirconium, titanium and silicon salts, have machining properties. In practice, only certain aluminum and zirconium salts have become established as combinatorial substances. Silicon compounds are practically not used because with starting materials which. they are mostly special water glass, difficult to handle in acidic engine media. In addition, the quality of leather, especially after aging, is generally insufficient, as it can cause stiffness, brittle onset and loss of tensile strength.

Description of the solution to a technical problem with a description of embodiments Used alkali aluminum silicates especially at. chrome tanning or. combination tanning with chromium, aluminum and silicon, tanning agents up to the following preconceptions:

1. By reducing the amount of kroner tanneries, a considerable reduction of the wastewater of the engine rooms is achieved. The chromium content is thus reduced in a proportional manner. By reducing the amount of chromium by 50% in the mixture, wastewater only takes up to 15% of the normal amount, as shown in Article di, compared to fully chrome tanning. ing. S. Felten v Wasser, Luft und Betrieb, 3, 1964.

2. The described disadvantages of silicon waxes are avoided because the alkali aluminum silicates dissolve in the tanning medium (pH 3-4.5) of sodium salt, aluminum salt and polymeric silicic acid in the finest distribution.

3. In combination tanning, alkalialumines.silicates are used with self-absorbing acidic use. The use of additional dissolving agents can therefore be waived. At the same time the machining performance is strengthened.

4. In the neutralization of chromium leather, alkali aluminum silicates used according to the invention may be used as neutralizers, without causing the leather to become unpleasant green due to polyphosphates. At the same time, they act as a camouflage salt, preventing the loss of highly basic chromium salts. In addition, a subsequent machine effect is achieved.

5. Salt and other electrolytes can be partially or completely saved by containing only small amounts of electrolytes in waste water compared to the normal process.

6. Alkalium aluminum silicates can be stored and handled without risk.

The subject of the invention is the use in the manufacture of leather of fine-grained water-insoluble, preferably water-containing alkali-aluminum silicates of the general equation (Kat2 / _n 0) _x . AlgO? - (SiO 2) y in which Kat is an alkali metal ion, preferably sodium ion, x number from 0.7 - 1.5, y number from 0.8 - 6, preferably 1.3 ..... 4, with a particle size of 0.1 to 25 μηι, preferably 1 to 12 μηι, demonstrating a calcium binding capacity of 20 - 200 mg CaO / g anhydrous active substance.

The ability of calcium to bind is determined by the procedure given in the example work i.

The alkali aluminum silicates which are useful according to the invention are manufactured in a simple manner, e.g. by reaction of water-soluble silicates with water-soluble aluminates in the presence of water. For this purpose, the aqueous solutions of the starting materials may be mixed with one another or in a solid state the component may be converted to another as an aqueous solution of the component.

Also, by mixing the solid components of the two components together, the desired aluminum silicates are obtained in the presence of water. Also from AlfOH) .-, AIoOt or Si0 _o can be converted, with alkalisilicate sj X- '-V X.

or the aluminum solution is made by alkali aluminum silicates. Finally, such substances are also formed from Stalin, but due to the high melting point required and the need to convert stalin to fine-grained products, this process seems less economically interesting.

Alkalium aluminum silicates, produced as sediment or by other processes transferred in a fine-grained state to aqueous suspensions, can be translated by heating to temperatures of 50 - 250'C from amorphous to aged or aged. to the crystalline state. In water suspension .....

The amorphous or crystalline alkali-aluminum silicate present can be separated from the remaining aqueous solution and dried .....

peraturi e.g. from 50 - 800 ° C. Depending on the drying conditions, the product contains more or less bound water. Anhydrous products are obtained at 800'C. However, water-containing products, especially such products, are preferred. as obtained when drying pr i 50 - 400 * C, especially 50 ..... 200C.

Suitable products may exhibit their total weight e.g. water content of about 2-30%, mostly about 8-27%.

The formation of the desired small particle size of 1-12 h may already be due to deposition conditions, by exposing the intermixed aluminate and silicate solutions, which can also be led simultaneously into the reaction vessel by strong shear forces, e.g. the suspension is vigorously stirred to produce crystallized alkali-aluminum silicates - these are preferably used according to the invention - thereby preventing the formation of larger, possibly piercing crystals by slowly stirring the crystallizing mass.

Nevertheless, unwanted agglomeration of crystalline particles may occur during drying, so it is recommended that these secondary particles be removed in an appropriate manner, e.g. with a branch. Even in the more severe state of the alkali aluminum silicate, which has been ground to the desired grain size, it can be used. For example, they are suitable for example. mills and / or feeders or their combinations.

Preferred products are e.g. synthetically produced crystalline alkali aluminum silicates composition

0.7 1.1. Floor ₂ / _n 0. Al ₂ ° 3 · 1.3-3.3 Si0 ₂ in which Kat is an alkali cation, preferably a sodium cation. It is useful when crystallites of alkali-aluminum silicates exhibit rounded corners and edges.

in order to produce alkali aluminum silicates with rounded corners and edges, it is advantageous to proceed from a nozzle whose molar composition is preferably in the range ₂ / _n 0. Al ₂ 0 ₃ .0.5 ..... 5.0 Si0 ₂ .60 200 H ₂ 0

2,5 - 6,0 Kat wherein the cat ₂ / _{n has} the meaning given above and means in particular the sodium ion. This nozzle is normally crystallized. In a preferred manner, this is done by heating the nozzle for at least 1/2 hour at 70 ~ 120 ° C, preferably at 80-95'Cp, while stirring. The crystalline product is isolated in a simple manner by separation of the aqueous phase. It is recommended that the product be washed with water and dried before further treatment. Also, when working with a single fitting whose composition deviates slightly from the above, products with rounded corners and edges are also obtained, especially if only one of the above four concentration parameters is varied.

Further, according to the invention, such < RTI ID = 0.0 > f < / RTI > grains of these water-insoluble alkali aluminum silicates, which have been obtained as a precipitate in the presence of water-soluble inorganic or organic dispersing agents and which have been aged or can be used, may also be used. crystallized. Such products are technically easily accessible. Surfactants, aromatic non-surfactant aromatic sulphonic acids, and compounds with complex calcium-forming capacity are suitable as water-soluble dispersants. Named dispersing agents can be introduced in any way before or during settling into the reaction mixture, e.g. like razto .....

foam or dissolve in alum and / or silicate solution. Particularly good effects are achieved if the dispersing agent is dissolved in a solution and is not a solution. The amount of dispersant should be at least 0.05% by weight, preferably 0.1-5% by weight, based on the entire settling portion. For aging or. crystallization is heated by settling product for 1/2 to 24 hours at a temperature of 50-200'C. From a variety of usable dispersing agents, they should be named e.g. natriumlauriletersulfate, sodiumpolyacrylate, hydroxyethanediphosphate and others.

In its crystalline structure, a particular variant of the alkali-aluminum silicates used according to the invention is a compound according to the general equation. :

0.7 ~ 1.1 Na ₂ 0. Al ₂ 0 ₃ .7 2.4 - 3.3 Si0 ₂

There are no differences with other so-called alkali aluminum silicates as a soap excipient.

A second embodiment of the presently useful fine-grained water-insoluble alkali aluminum silicates is represented by the compound of the formula:

0.7 - 1.1 - At ₂ 0. Al ₂ 0 ₃ > 3.3 - 5.3 Si0 ₂

In the manufacture of such products, we proceed from an attachment whose molar composition lies primarily in the field of:

2.5 - 4.5 Na ₂ 0; Al ₂ 0 ₃ ; 3.5 - 6.5 Si0 ₂ ; 50 - 110 H ₂ 0

This nozzle is normally crystallized. Preferably this is done by heating the nozzle while vigorously stirring for 1/2 hour at 100-200'C, preferably at 130-160'C. The crystalline product is isolated in a simple way by separating the liquid phase. Afterwards, wash with water and dry at 20-200'C. Thus dried products contain bound water. If we make the products as described in this way, we get very fine crystallites that fold together into globular particles, possibly into hollow spheres about 1 to 4 pm in diameter.

Suitable for use according to the invention are alkali-aluminum silicates, which can be made from calcined (destructured) kaolin by hydrothermal treatment with aqueous alkali hydroxide. The product of the true equation is:

0.7-1.1 Floor ₂ / _n 0. Al ₂ 0 ₃ . 1,3-2,4 Si0 ₂ . 0.5-5.0 H ₂ 0 wherein Kat is an alkaliation, in particular sodium cation. The production of alkali-aluminum silicates from calcined kaolin leads directly to a very finely divided product without special technical effort. Hydrotherm.1 to treatment previously at 500 to 800 ° C of calcined kaolin is carried out with aqueous. alkali hydroxide at 50 to 100 ° C. The resulting crystallization reaction is generally complete after 0.5 - 3 hours.

The commercially available washed kaolins exist predominantly from the clay mineral kaolin of approximately Al ₂ 0 ₃ composition. 2 Si0 ₂ . 2H ₂ 0 having a layered structure. In order to achieve this by hydrothermal treatment with alkalihydroxide to the alkali aluminum silicate used according to the invention, it is first necessary to destruct the kaolin, which is most efficiently carried out by two to four hours of heating the kaolin at temperatures from 500 to 800 ° C. from kaolin an x-ray amorphous anhydrous metakaolin. In addition to the calcins injured, the destruction of kaolin can also be achieved by mechanical treatment (milling) or acid treatment.

Kaolins as a starting material are bright powders of high purity, but in any case their iron content is about 2000 to 10 000 ppm Fe significantly higher than the values of 20 to 100 ppm Fe in alkali-aluminum silicates made from alkalisilicate and alkali-aluminate solutions by deposition. This higher content of kaolin-made alkali-aluminum silicates is not a disadvantage, as iron in the form of ferric oxide is firmly embedded in and cannot be released from it. The hydrothermal effect of sodium oxide on the destructured kaolin produces sodium aluminum silicate with a cubic, faujasite-like structure.

The alkali aluminum silicates which are useful according to the invention can also be made from kalyinated (destructured) kaolin by hydrothermal treatment with aqueous alkali hydroxide with the addition of silicon dioxide or a compound giving silicon dioxide. In this case, the generally obtained mixture of alkali-aluminum silicates of different crystalline structure consists of very fine-grained crystalline particles having a diameter of less than 20 µm and consisting mainly of 100¾ of particles smaller than 10 µm.

In practice, this conversion of the destructured kaolin is carried out preferably with a sodium hydroxide and water glass. This produces sodium silicate J, which has been identified in the literature by several names, e.g. as a 13Χ molecular sieve or Zeolite NaX (cf. O.Grubner, P. Jiru and M Ralek, Molekularsiebe Berlin 1968, 32, 85--89), if the attachment is not preferably stirred during hydrothermal treatment, a little shear energy is introduced in every way, and preferably at a temperature of about 10-20 ° C below the boiling point (about 10 3'C), Natriumaluminum silicate J has a naturally occurring faujasite-like cubic crystal structure. The conversion reaction can be influenced, in particular, by mixing the attachment, with an elevated temperature (boiling temperature at normal pressure or in an autoclave) and larger quantities of silicate, that is, by a molar ratio of the SiC ^ attachment: Na ₂ 0 at least 1, in particular 1.0 - 1 , 45, so that it arises in addition to or. instead of sodium silicate J sodium sodium silicate F.

Natriumaluminum silicate F is referred to in the literature as Zeolite P or type B (cf. D.W. Breek, Zeolite Molecular Sieves, New York 1974, p. 72). Natriumaluminum silicate F has a naturally occurring Gismondin and Garronite zeolite structure and has the appearance of external spherical crystallites. In general, the manufacturing conditions for sodium silicate F and mixtures of J and F are less critical than for pure crystalline type A.

The degreasing and coating of bare skins is carried out in a known manner e.g. in the machining barrel. Alkalium aluminum silicates are preferably introduced in combination with surfactants, in particular anionic and non-ionic surfactants. Higher sulphates or sulphonates with 8-18 C atoms, such as primary and secondary alkyl sulphates, alkyl sulphonates or alkali lsul fo-nates, are particularly suitable as anionic surfactants. Suitable non-ionic surfactants are, for example, adducts of 5 to 30 moles of eLilenoxide to higher fatty alcohols, alkylphenols, fatty acids or fatty amines of 8-18 atoms C. Anionic and non-ionic surfactants can be used advantageously in mixtures, but also individually with respect to washing goods. In addition, it is possible to add alkali-aluminum silicates as separate auxiliaries to conventional mixtures or to use them in conjunction with a smaller proportion of acidic chromium solvents combined.

In the case of the process according to the invention, 10 - 50 g / l surfactants and 10 ..... 50 g / l alkalium aluminum silicates are required.

In order to support the fat-melting effect of the cleansing mixture in degreasing heavily fatty bare skin, fatty solvents in quantities of 50-100 g / l may be further added. Suitable solvents are selected from the group of petroleum hydrocarbons, hydro-aromatics, alkylbenzols and mineral oils. In general, however, the use of solvents may be waived.

Tanning of fur skins and leather is also carried out in the usual way, depending on the type of leather known to the tanner, e.g. Vegetable-synthetic tanning agents, chromium tanning agents, etc. with the addition of electrolytes such as table salt, inorganic and organic acids such as sulfuric acid, formic acid or acidic acid, etc. Pickling and tanning can be combined in a known way. Subsequently, the tanning and fatting of the leather may be carried out.

The use of alkali aluminum silicates in the named tanning processes amounts to 5-80 g / l of the tanning mixture.

Alkaluminium silicates can also be useful in neutralizing leather, since they are converted into an acidic medium by acid binding and the formation of alkali and aluminum salts as well as polymeric quartz acids. In this case, 2 to 20 g / l of alkali aluminum silicate is required.

The use of the fine-grained, water-insoluble alkali-aluminum silicates according to the invention achieves the previously described advantages over the processes so far. Alkalialumini silicates can be translated as /, dry powders by mixing with water or a dispersing agent.

I containing solutions in stable dispersions and can be well handled in this form and easily diluted with water.

Production of suitable alkali aluminum silicates

In a container containing 15 l, an aluminate solution was mixed while stirring vigorously in a silicate solution. It was mixed with a dispersion plate mixer at 3,000 rpm. Both solutions had room temperature. It was formed by exothermic reaction, as a product of primary sediment, rontgenamorphic sodium silicate. After stirring for 10 minutes, suspensions of the product of deposition were transferred to the crystallization vessel, where it remained at 90 ° C for 6 hours while stirring (250 rpm) for crystallization purposes. After suction of the pool of crystalline slurry and subsequent washing with diluted water until the effluent showed a pH value of about 10, the filter residue was dried. Instead of dried natriumaluminum silicates, a suspension of the crystallization product or a so-called crystallization product was used to make soap auxiliaries. crystalline. The water content was determined by heating the pre-dried product to 800 ° C for one hour. Up to a pH of about 10 washed or washed. the neutralized and then dried sodium silicates were subsequently ground in a ball mill. The grain size distribution was determined using a sedimentation balance.

The Ca Al-silicate bonding ability was determined as follows: 11 aqueous, 0.594 g CaCl? (= 300mg CaP / l = 30 ° dH) containing and diluted NaOH to a pH value of 10 the adjusted solution is mixed with 1. g aluminum silicate (relative to AS). Then it .....

it is stirred vigorously for 15 minutes at 22 ° C (-? 'C). After filtering the aluminum silicate, the residual hardness x of the filtrate is determined. From this, we calculate the ability to bind calcium in mg CaO / g AS by the equation: (30 - x) .10.

if the ability to bind calcium at higher temperatures is determined, e.g. at 60 C C, we always find better values than 22′C.

Manufacturing conditions for sodium silicate A:

Precipitation: 2,985 kg of aluminate solution with composition: 17.7% Νει ^ Ο, 15.8% Al ₂ 0 ₃ , 66.6% H ₂ 0

0.15 kg etched natron

9,420 kg of water

2,445 kg of commercially available water glass and lightly alkali-soluble quartz acid freshly made 25,8% natrium silicate solution with the composition: lNa _? O.6,0Si0 ₂

Crystallization: 6 hours at 90 ° C

Drying: at 100 ° C for 24 hours

Composition: 0.9 Na ₂ 0. 1 Al ₂ 0 ₃ . 2.04 Si0 ₂ - 4.3 H ₂ 0 (= 21.6% H ₂ 0)

Crystallization rate: Full crystalline

Calcium binding capacity: 170 mg CaO / g of active substance.

In the sedimentation analysis, the maximum particle size distribution at 2 - 6 pm was determined.

Natriumai soothed silicate A shows in the X-ray diffraction pattern of the following interference line;

about the d value recorded with Cu ..... ..... in A:

I

12,4

8.6

7.0

4.1 (+)

3.68 (+)

3.38 (+) 3.26 (+) 2.96 (+)

2.73 (+)

2.60 (+)

It is quite possible that not all of these interference lines appear in the X-ray diffraction diagram, especially if the aluminum silicates are not completely recrystallized. Therefore, the most important d-values of Z (+) have been designated as the! Character.

Manufacturing conditions for sodium silicate B:

Precipitation: 7.63 kg aluminate solution composition: 13.2% NA _? O; 0.8% Al ₂ 0 ₃ ; 78.8% H _? 0;

2.37 kg of sodium sodium silicate solution composition: 8.0% Na ₂ 0; 26.9% SI0 _2; 65.1% H _? 0;

Mounting ratio in Mols: 3.24 N ^ O; 1.0 A1 ₂ 0 ₃ ; 1.78 Si0 ₂ ;

70, h> 11 ^ 0;

Crystallization: 6 hours at 90'C

Drying: 24 hours at 100 * C

Composition of the dried product: 0.99 Na? 0. 1.00 Al ₂ 0 ₃ . 1.83 Si0 ₂ 4.0 H _? 0; (= 20.9% H ₂ 0)

Crystal shape: cubic with strongly rounded corners and edges; Mean particle diameter: 5.4 pm

Calcium binding capacity: 172 mg CaO / g of active substance.

Conditions for the production of sodium silicate C:

Precipitation: 12.15 kg aluminate solution of composition: 14.5 Na ₂ 0; 5.4% Al ₂ 0 ₃ ; 80.1% H ₂ O; 2.87 kg of sodium sodium silicate solution composition: 8.0% Na ₂ 0; 26.9% SI0 _2; 65.1% H ₂ O;

Molar Ratio: 5.0 Na ₂ 0; 1.0 Al ₂ 0; 2.0 Si0 ₂ ; 100 H ₂ O;

Crystals. raid: 1 hour at 90 ° C Drying: hot wash of the product suspension (pH 10) at 295 ° C; a solids content of 46%; Composition ( - »Dried product: 0.96 Na ₂ 0. 1 Al ₂ 0 ₃ . 1.96 Si0 ₂ . 4 H _? 0 The form of which istal: cubic with strongly rounded corners and edges, water content of 20.5%; Medium | jremer particle. 5,4 pm The ability calcium binding: 172 mg CaO / g of active substance.

Conditions for the manufacture of potassium aluminum silicate D:

It was first made sodium silicate C. After suction

master lye and wash crystalline rass with razmineral i.zi wound water all the way to the pl 1 of value 10, the filter residue was reduced to mucus v 6,1 1 25 percent KC1 solution. Suspension and. ja was briefly heated to 80 ~ 90 ° C. Then it is was oh h price and re-filtered and washed. Drought e; 24 hours at 100 ° C;

Composition of the dried product: 0.35 Na-> 0. 0.66 K-> 0 1.0 Α'1ς> 0 _χ

Z. x_.

. 1.96 SiO? . 4.3 H ₂ O; (water content 20.3%)

Conditions for the production of sodium silicate E:

Precipitation: 0.76 kg of aluminate solution composition:

36.0% Na ₂ 0, 59.0% Al ₂ ° 3 ' ⁵ > °% water;

0.94 kg etched natron 9.49 kg water

3.94 kg of commercially available natrium silicate solution composition: 8.0% Na ₂ 0, 26.9% Si.O ₂ , ^ ⁵ '1% ^ 2 °'

Crystallization: 12 hours at 90 ° C

Drying: 12 hours at 100 ° C

Composition: 0.9 Na o0 - 1 A1 ₂ 0 »1 S and 0 <7. 5 H ₂ O;

Crystallization rate: Full crystalline

The maximum particle size was at 3 - 6 μηι

Calcium binding capacity: 110 mg CaO / g of active substance

Aluminum silicate E shows in the X-ray union diagram the following interference lines:

d-values recorded with Cu radiation in 8;

14,4

8.8

2.88

2.79

2.66

Conditions for the production of sodium silicate F:

Precipitates at: 10.0 kg aluminate solution composition:

0.84 kg NaA10 ₂ t 0.17 kg NaOH + 1.83 kg H ₂ 0;

7,16 kg natriumsilicate solution composition:

8.0% Na ₂ O, 26.9% SiO ₂ , 65.1% H ₂ O;

Crystallization: 4 hours at 150 ° C

Drying: hot question 30% suspension of the washed product (pH 10)

Composition of the dried product: 0.98 to ₂ 0. 1 Al ₂ 0j. 4.12 Si0 ₂ . 4.9 H ₂ O;

The particles have the shape of a sphere, with an average diameter of about 3

- 6 μ m.

Calcium binding ability: 132 mg CaO / g of active substance at 50'C.

Conditions for the production of sodium silicate G:

Precipitation: 7.31 kg of aluminate (14.8% Na ₂ O, 9.2% Al ₂ 0 ₃ ,

76.0% H _? 0)

2.69 kg of silicate (8.0% Na ₂ O, 26.9% SiO ₂ , 65.1% H ₂ O); Sole ratio in Mols: 3.17 Na ₂ 0 1.0 Al ₂ 0 ₃ , 1.82 Si0 ₂ , 62.5 H ₂ 0;

Crystallization: 6 hours at 90 ° C;

Composition of the dried product: 1.11 Na ₂ 0. 1 Al ₂ 0 ₃ . 1.89 Si0 ₂ ,

3,1 H _? O (-16.4% H ₂ O);

Crystal structure: a structural mixture of types in a ratio of 1: 1 Crystal shape: rounded crystals;

Mean particle cross-section: 5.6 μη.

Calcium binding capacity: 105 mg CaO / g of active substance at 50'C

Terms of manufacture of kaolin-made sodium silicate H:

1. Destruction of kaolin

To activate the natural kaolin, mackerel of 1 kg was heated for 3 hours at 700 ° C in a chamotte smelter. In this, the crystalline kaolin Al ₇ 0 ₃ was converted. 2 Si0 ₂ . 2 H ₂ 0 to the amorphous metakaolin Al ₂ 0 ₃ .. 2 Si0 ₂ .

2. Hydrothermal treatment of metakaolin

Alkali alkali was poured into the mixing vessel and calcined kaolin was stirred at temperatures between 20 ° C and 100 ° C. The slurry was heated to a crystallization temperature of 70-100 ° C during stirring and maintained at this temperature until completion.

2.2 crystallization process. The mother liquor was then aspirated and the residue was washed with water until the effluent wash water showed a pH of 9 to 11. Drank three wounds. > and hi 1 dried and then ground to fine powder, respectively. was ground for removal by drying the resulting agglomerates. This grinding process was canceled if the filter residue was further treated or if spray or stream drying was carried out. Hi .....

dermal treatment of calcined kaolin can also be carried out in a continuous working process.

Nozzle: 1.65 kg of calcined early kaolin

13.35 kg NaOH 10%, stirring at room temperature;

Crystallization: 2 hours at. 100'C

Drying: 2 hours at 160 * C in a vacuum drying jacket i.

Composition: 0.88 Na _o 0. 1 Al _o 0 ₇ . 2.14 SiOo. 3.5 H _Q 0 / L, X «XŠ X— (= 18.1% H _? 0);

Crystal structure: a structural mixture of types such as Na-Λ1uminium silicate G but an 8: 2 ratio

Mean particle diameter: 7.0 pm

Calcium binding capacity: 126 mg CaO / g of active substance.

Terms of manufacture for kaolin-made sodium silicate J:

The destruction of kaolin and hydrothermal treatment was performed in an analogous manner to that of H:

Extension: 2.6 kg of calcined kaolin,

7.5 kg NaOH, 50 percent,

7.5 kg of water glass,

51.5 kg of ionized water, stirring at room temperature

Crystallization: 24 hours at 100 ° C without stirring.

Drying: 2 hours at 160'C in a vacuum oven

Composition: 0.93 Na ^ O. 1 Al ₂ 0 ₃ . 3.60 SiO _? . 6.8 H ₂ O (= 24.6% H ₂ O);

Crystal structure: Sodium aluminum silicate J by previous definition, cubic crystallites;

Mean particle diameter: 8.0 pm

Calcium binding capacity: 105 mg CaO / g of active substance.

EXAMPLES

Example 1

Degreasing and coating of sheep's skin for vegetatively tan leather

Sheep's bare skin (pH 1.8 per shin) is rolled in a barrel for 90 minutes with 38% C water% alkylphenol polyglycol (9.5 AO)% Na "Al-silicate according to the case of Α, Β, Ε, and then diluted with 100¾ of water at 38 ° C and continue to boil for 60 minutes (ptl gaps 3.8--4.0). The mixture is discarded and rinsed at 35 ° C for 1.5 minutes ...

Tanning:

Skimmed and degreased bare skin with

100% water 25 ° C% synthetic light and soap tanning agent commercially available type of roller for 15 minutes, then% additive commercially available on persistent agents

7.Ά soaking, 45 minutes roll in the same mixture;

% mimosal powder (powder) 7 a total of 10% guebracho powder (powder) -J added and 4 hours are machines.

The leather is then in a new blend, treated with 100% water and 0.5% ok saliva for 30 minutes and made brighter, leaving · η stable. pH in the bath at about 4, .1.-4,2.

After rinsing the leather at 25 ° C for 10 minutes, the leather is stretched as usual and dried. Without ecologically sound, otherwise necessary higher salt and polyphosphate amounts, degreasing and pre-coating results in good quality leather.

Example 2

Degreasing and coating of sheep's skin for chrome tanned hooded leather:

Bare skins with the meat removed are degreased and redistributed as in Example 1 (pH '3.8-4.0 per shin). They are then rinsed at 35 ° C until the pure mixture drains.

Tanning:

100 vode water 25 ° C% commercially available, chromium persistent synthetic t1 toughened 30 minutes in a barrel, then addition of% commercially available soap tanner: tanning time 5 hours (pH about 3.8 in bath) , the leather hangs on the racks for 1-2 days and then wears off.

Post-tanning:

200% water 45 ° C minute rinsed, new mixture,

100% water 45 ° C,% soap tanning, commercially available chromium tanner 15 minutes, pour time,% on chromium tanner with a stable and light resistant grease - 45 minutes,% soap tanning, neutral auxiliary tanner, flow time 30 minutes, pH 4.4 in a bath, then rinse p>'i 50 ^a C for 10 minutes,

Revenge:

150¾ water 50 ° C,

5-7% commercially available softening, natural or synthetic leather grease, 45 minutes flow time.

The leather is further processed and dried in the usual way. In this way, without the usual and necessary sharing of cooking salt or polyphosphates, we obtain good quality pickle and grease.

Example 3

Tanning of sheep fur

Well-washed and possibly trimmed sheep fur for 15 minutes: rinsed at 35 ° 0 in the skin spindle.

Imitation and tanning

Water '0-35'C, mix ratio 1:20 ,.

g / 1 table salt, g / 1 commercially available, electrolyte-resistant skin grease, 30 minutes, g / 1 organic low molecular weight acid, e.g. formic acid acid formic acid, duration 3 hours.

Allow to lie in the bath overnight.

4-5 g / l of commercially available chromium powder powder, g / 1 of Na-Al-silicate according to Example A, B, C for a duration of 3 hours, then let stand overnight (pH about 4.0 in the mixture), then Rinse for 15 minutes, hang on racks and dry hung.

In this way, between 1/3 and half of the usual amount of chromium solvent is saved, which results in the ecologically contentious content of chromium in waste water. at about 0.5 g / l without. suffered from sheepskin quality.

Example 4

Chromium tanning of bovine upper leather

In the usual way 1 baked, crucified and leavened beef bare skin is rinsed after a brief rinse! at. 20 ° C with:

Tapping and tanning together:

100% water 20 ° C ® '. table salt for 10 minutes, then the addition of 0.6 t of formic acid, for 20 minutes.,

0.6% sulfuric acid, 2 hours overnight in a bath (pH 3.5 per shave),

1; commercially available crystalline powder in powder, t Na ..... Al-silicate after case h, C, D, duration 5 hours (pH about 3.8 in bath).

The tanned leather is hung overnight on the racks, then it waxes, then with threes and grease. The leather is then dried and finished as usual.

In this way, the chrome tanner offered can be reduced from the normal 10¾ to less than 8%, without reducing the quality of the leather, at. leaving the chromium content of the wastewater from about 8 g / l CrgOj ^to less than 1 g / l.

Example 5

Neutralization of bovine upper leather

The processing is carried out as in Example 4.

Neutralization

Wash the leather (pH 3.7-4.2) at 35 ° C for 10 minutes

100% water 35 ° C,

0.5 - l% Na-Al-silicate according to Example B, G, F.

time t 30 minutes.

pH in leather cut 4.5 - 4.7.

Further work as in Example 4.

In this way we get a 'neutralizing effect' associated with a particular

I after tanning, noting the effect of o.

Example 6

Tanning of white bovine leather:

Pre-treatment of bare skins, including crucifixion and salting, is carried out in the usual way.

Tapping and tanning together:

100% water 20′C% k in Ii and n j s ke salt, duration of 10 minutes,

0.7% formic acid - 15 minutes.

0.7% sulfuric acid - 2 hours,

Overnight, bare skin remains in the bath of picnicking (pH 3, in the skin incision).

% Na-Al-silicate of Example A, C, D, F into the same bath.

1.5% sulfuric acid - duration of 5 hours (pl) about 4.2 in the bath).

Then put it on the racks and measure.

Post-tanning and revenge:

Mild leather is rinsed 10 rnuts at 40 ^a C and treated in a new mixture with:

100% water 40 ° C neutral mild and light tan synthetic triple aid1a 30 minutes duration.

.1.0% for white leather suitable, commercially available, electrically .....

casters and grinders of a permanent degreaser. duration of 45 minutes.

% commercially available white tanner for 30 minutes in the same mixture.

New mix.

200% water 45 ° C

0.3% oxalic acid,, _______

time f; paradise a 15 minutes.

Place the leather on the racks and dry the hanged. With this combination of Na-Alsi 1ikats with white machineries, leather is more solid, with higher water resistance of commercially normal quality, compared to conventional tanning with aluminum machineries and white machinists.

Claims (9)

1. The use of fine-grained, water-insoluble, preferably water-containing alkali-aluminum silicates according to the general equation (Kat _{2 / n} 0) _x . fll ₂ 0 ₃ . (Si0 ₂ ) _y , in which 'Kat is an alkali metal ion, preferably sodium ion, x Number 0.7-.1.5, y number 0.8-6, preferably 1.3-4, / large ·;!. · ··· particles of 0.1 to 25 pm, preferably 1 to 12 pm, which demonstrate the ability of calcium to bind 20 - 200 mg CaO / g of water of the free active substance in the manufacture of leather. Use of fine-grained alkali aluminum silicates according to claim 1, characterized in that such products are used which correspond to the general, Eq. 0.7 - 1.1 Floor ₂ / _n O. Αΐ ₂ θ3 · 1.3–3.3 Si.0 _? Use of fine-grained alkali-aluminum silicates according to claim 1, characterized in that such products according to the general equation are used 0.7 - 1.1 Na ₂ 0, Al ₂ 0 ₃ . > 2.4 - 3.3 Si0 ₂ Use of fine-grained alkali-aluminum silicates according to claim 1, characterized in that such products according to the general equation are used - 1.1 Na ₂ 0. Al ₂ 0 ₃ . > 3.3 - 5.3 Si0 _? 0.7 610 5. The use of fine-grained alkali aluminum silicates according to claim 1, characterized in that the calcined kaolin-manufactured products according to the general equation are used 0.7 - 1.1 Kat _{? / N} 0. Al ₂ 0 ₃ . 1,3-2,4 Si0 ₂ . 0.5-5.0 Η _; , 0 Use of fine-grained alkali-aluminum silicates according to claim 1 -5 in combination with anionic and / or non-ionic surfactants in amounts of 10-50 g / 1 silicate and 10-50 g / 1 surfactant for degreasing and protrusion of warty skin. Use of fine-grained alkali aluminum silicates according to claim 1-5 in combination with adducts of 5-30 moles of ethylene oxide to higher fatty alcohols, alkylphenols, fatty acids or fatty amines of 8-18 C atoms for degreasing and pre-te ration of warty bare skin . The use of fine-grained alkali aluminum silicates according to claim 1-5 in an amount of 5-80 g / l for tanning and lining fur and leather in combination with chromium, synthetic and / or plant machinery. Use of fine-grained alkali-aluminum silicates according to claim 1-5 in an amount of 2 to 20 g / l to neutralize the leather.