FI77436B - FOERFARANDE FOER FRAMSTAELLNING AV ETT FLYTANDE AEMNE FOER FOERBAETTRING AV ORENAT VATTENS KVALITET. - Google Patents

Description

η 77436

METHOD OF MANUFACTURING A LIQUID SUBSTANCE FOR IMPROVING THE QUALITY OF CONTAMINATED WATER - FOR THE PRODUCTION OF A LIQUID SUBSTANCE - FOR THE FRAME STATION AND FOR THE FLIGHT AND FOR THE CONSTRUCTION OF WATER QUALITY

5

The invention relates to a process for the preparation of a liquid substance for improving the quality of contaminated water, in particular swimming pools, natural bodies of water and waste water.

10 There are countless substances to improve the quality of water, such as swimming pools, beaches and sewage. Not only do these known substances require close monitoring and great care in their use, but their use may be prohibited because they often contain corrosive and toxic chemicals that can lead to health damage if misdosed.

AT 324 967 discloses a substance for purifying contaminated water based on an alkaline aqueous solution or slurry of inorganic salts. However, there is no reference in this patent publication to how this known substance can be prepared.

It is an object of the invention to provide a simple process for the preparation of a generally useful substance of the type described in the preamble, starting from naturally occurring substances.

According to the invention, this is achieved by adding to the aqueous solution or slurry 30 of the inorganic base, with stirring, a comminuted naturally occurring mixture of clay, common salt and gypsum ("Haselgebirge") and / or the extraction residue of such mixtures ("Werkleist") obtained from salt extraction. 2-5, preferably 3 h, that the pH of the resulting solution 35 is adjusted to between 7.5 and 10.5, preferably 9.5-10.5, with the addition of acid or lye if necessary, and that the solution is separated from the insoluble constituents.

2 77436

The method according to the invention is not only sourced from inexpensive raw materials, but is also extremely simple. Thus, the concentrations of the substances involved in the reaction (salt layer and possibly the salt layer-5 nucleus extraction residue and base) are not critical. Simple indicative experiments are sufficient to give optimal proportions and minimum quantities. Since the substance prepared according to the invention is a solution, any excess of the substance involved in the reaction is not disturbed, since it remains chemically unchanged in the residue.

Preferably, an aqueous solution or slurry having a pH of more than 10, preferably more than 12, is used.

In particular, starting from the extraction residue of the salt deposit, it is advantageous if solids (salt deposit, extraction residue of the salt deposit or a mixture thereof) with a NaCl content of between 20 and 80% by weight are added to the solution. In this case, it is recommended that before adjusting the pH to 20 to the final value, the table salt content of the solution is increased by adding table salt to the desired value of about 14 g NaCl / l solution and optionally adding table salt in the form of an aqueous solution, e.g. brine, preferably 28% NaCl.

What base is used in the process of the invention is not critical. Of particular value are calcium oxide, calcium carbide and sodium hydroxide.

The salt layer ("Haselgebirge") used in the context of the invention is a mixture of clay, salt and gypsum, found mainly in the Salzkammergut and the Berchtesgaden Alps. The extraction residue of a salt deposit ("Werk-leist") is a residue remaining when the salt is dissolved, which differs from the salt deposit ("Haselgebirge") on the basis of a substantially lower salt content or its absence.

The following are analyzes of two salt-rust samples (deep-drilled borehole flour

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1 77436 in Hallstatt): Sample 1 H 2 O soluble fraction (10 g sample / 500 ml dist. H 2 O) - 63% containing: 5%%

Ca— 3,778 CaSo4 12,833

Mg-- 0.244 MgCl 2 0.957 SO 4 - 9.477 Na 2 So 4 0.623

Cl- 52.445 NaCl 84.725 10 K- 0.386 KCl 0.736 H 2 O insoluble fraction (10 g sample / 500 ml dist. H 2 O) - 37% containing: ry

O

15 CaO 0.350

MgO 9.325 SO 3 0.729 K 2 O 12.494

SiO 2 49,740 20 Sesquioxide 27,215 Sample 2 H 2 O soluble fraction (10 g sample / 500 ml dist. H 2 O) - 33% containing: 25%

Ca— 5,602 CaSO 4 19,028

Mg - 1.279 MgCl 2 5.009 SO 4 "15.101 Na 2 SO 4 2.476

Cl- 48.039 NaCl 72.181 30 K- 0.580 KCl 1.106 Insoluble fraction of H 2 O (10 g sample / 500 ml dist. H 2 O) - 67% containing: ... '% 35 CaO 0.736

MgO 7.939 SO3 0.986 7 7 4 3 6 K20 10.916

SiOa 51,160

Sesquioxide 27,810 5 The average concentration of alpine salt clay from the salt deposit ("Haselgebirge") (averages 14 analyzes with alkali assays) can be seen in Table I.

10 TABLE I

Group Group black salt clays green-gray salt clays Stone types black, black green green gray gray gray 15 anhydr. -black -green (Hall, (Hallein) salt clay Tyrol) A1203 15.80 17.50 18.85 20.21 22.20 16.75 19.80

SiO 2 45.24 43.20 46.00 49.20 50.34 61.65 52.86

MgO + CaO 16.28 15.60 12.16 10.80 9.36 7.82 10.10 20 (KNa) O 3.12 4.48 5.19 4.01 4.41 3.14 4.04

Fe 2 O 3 + FeO 5.60 7.00 7.20 7.33 8.53 5.81 5.98% conc. 86.04 87.78 89.40 91.55 94.84 95.17 93.36

Mineral components (averages) 25 Clay alkali silicates 42.36 49.01 56.64 60.60 60.73 47.93 55.94

Mg-Hydrosilik.16.70 17.80 17.49 16.70 17.65 14.98 18.50

Quartz 14.98 9.62 7.77 8.29 10.39 29.12 14.01

Anhydride 16.16 4.82 1.94 1.28 0.94 1.24 1.36 30 Calcite - - 0.75 0.92

Dolomite - 0.82 0.29 0.40 -

Magnesite 4.20 10.93 7.06 5.17 0.95 to 3.62

Sum of Fe oxides and by-products 35 5.60 7.00 8.81 7.56 8.69 5.31 6.57% of total 100.00 100.00 100.00 100.00 100.13

Specific gravity 2.77 2.75 2.74 2.73 2.77 2.78 2.75

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; 77436

The process according to the invention preferably uses a salt bed with a common salt content of 20 to 80%, preferably between 30 and 50%. A salinity of about 5 to 40% has proven to be particularly advantageous.

If the salt content in the salt layer used is too high, it is possible to use a salt layer mixed with the extraction residue of the salt layer. The extraction residue of the salt deposit is the residue remaining in the extraction of 10 table salts by the extraction method, and the residue of the Rotsalz Mountains in Hallstatt gives, for example, the analyzes given in Table II.

TABLE II 15

Water soluble: 6.73% Of which NaCl 3.70% 30

Insoluble in water: 93.27% (separated at 120 ° C)

Specific gravity 2.67 20 SiO 2 49.72% Al 2 O 3 20.50%

Fe 2 O 3 8.00%

CaO 0.91%

MgO 10.59% 25 K 2 O.

Na 2 O 4.50%:: CO 2 1.19% SO 3 0.74% H 2 O 3.84% 30 30 can rise to 15% (with a water solubility of 18%)

The chemical composition of the extraction residue corresponds to the chemical composition of alpine salt clay, as shown in Table III.

35 6 77436

TABLE III

Chemical composition of alpine salt clay (within limits) Illiitti Alpine salt clays

SiO 2 44 - 52.2% 42.5 - 53% 5 Al 2 O 3 21.5 - 32.8% 17.4 - 23%

Fe 2 O 3 2.3 - 6.2% 5.6 -8%

FeO

MgO 1.3 - 3.9% 8.0 -13.5%

CaO 0.0 - 0.9% 0.3 -2.3% 10 Na 2 O 0.1 - 0.9% 0.1 - 2.5% K 2 O 4.8 - 7.7% 2.8 - 5, 1%

MnO 0 - 0.1%

TiO 2 0 - 0.7% H 2 O 8.5% 1.8 - 5.8% 15

In detail, the preparation process according to the invention proceeds as follows: 1. The base (burnt lime, calcium carbide, soda liquor) is gradually added to water, whereby the pH of the solution or slurry obtained is above 12.

2. To this strongly alkaline solution, a salt layer ("Haselgebirge") is added with stirring, e.g. in the form of drilled flour. Instead of drill flour, a salt layer extraction residue ("Werkleist") or a mixture thereof can also be used. The amount added adapts to the edible salt content of the solids, which can be between 0% (salt deposit extraction residue) and 20 to 80% (salt deposit). The higher the NaCl content (lower silicate content), the more the salt layer is then added.

3. The resulting mixture is stirred to activate the clay (swelling) for about 2-4 hours.

4. To improve the electrolytic properties, in particular with a high degree of salt deposition change (i.e. with a lower NaCl content of the solids given in point 2), crude salt water (28% NaCl) is added. In total, the solution must be

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7 77436 si 2 - 20% NaCl.

5. After repeated stirring for 1 to 3 hours and possibly after dilution with water - especially when 5 less water was originally used - the pH is adjusted to 9.0 to 11.0, preferably 9, with a base or acid (e.g. hydrochloric acid). , from 5 to 10.5.

6. After settling of the insoluble constituents (takes 5 to 10 hours), decant the remaining 10, colorless, clear solution.

The substance prepared according to the invention has excellent properties and its addition causes a significant improvement in water purification and quality. Especially in the field of water treatment, practical and scientific data are of primary importance: in order to determine the possibilities of use in the case of wastewater, four wastes of different types were treated with varying addition rates. agent.

The test water used was: 20 1. Water from a municipal mechanical treatment plant 2. Water from a brewery (direct supply) 3. Water from a dairy company (direct supply) 25 4. Water from a hospital (third chamber, chlorinated 0.2 mg / 1 chlorine)

The experiment determined: a) sedimentation time b) decay 30 c) oxygen consumption d) oxidizability e) biological oxygen demand In this case, the corresponding equivalence values were found: 35 a) shorter b) long c) low 77436 d) low e) low undoubtedly the positive effect of the substance prepared according to the invention on the quality of the effluent.

Similarly, a substantial improvement in flocculation in public swimming pools can be observed in conjunction with chlorination instructions; in this connection, the chlorine content of bathing water can be reduced, ensuring perfect water quality by an order of magnitude of 50% of the amount used so far, which undoubtedly represents a welcome step towards a chlorine-poor and more pleasant bathing water.

In order to study the effectiveness of the substance to be prepared according to the invention, water purification was compared with conventional substances and with the substance according to the invention.

In this case, the substance prepared according to Example 1, hereinafter simply referred to as "substance", was used.

1,100 Preliminary tests 20 To investigate the efficacy of the substance and the performance of the stallions for the following experiments, experiments were performed in the laboratory, including: 1.101 Reduction of harmful substances For this purpose, a solution containing 25 specified amounts of phosphate and nitrate was mixed with increasing amounts and, after different reaction times (room temperature) and to distinguish between the categories formed after fine filtration (blue ribbon), the phosphate and nitrate concentrations in the filtration were determined compared to the blank.

In this case, it could be found that in the filtered liquid, phosphate and nitrate were reduced by an order of magnitude of 40% compared to the test solution.

This effect is known in water purification technology 35 as "clarification" and can be explained, as is known, by the fact that oxide hydrate particles, such as iron and / or Aluminum particles and li, 77436 e.g. activated silicas, have a high energy content solutes (adsorbates) are deposited through ad-sorption.

5 No comparable reductions in phosphate and nitrate were observed with aluminum sulphate and ferric chloride.

1.120 Effect on flocculation

The substance exhibits flocculating properties, which, however, in combination with a directed flocculant, in this case the so-called with polyaluminium hydrochloride (PAC) shows a surprising improvement in flocculation - compared to aluminum hydroxide.

15 In addition, despite the fact that flocculation itself is substantially accelerated, coagulation proves to be even more intense, even when only 0.3 ml / m3 is used.

In contrast, commercially available liquid-flocculants have a PAC value of between 0.5 and 1.0 ml / m3 according to their product descriptions.

Based on its effect on flocculation, the substance is thus comparable to a "synergistic enhancer" (your activator, accelerator). In this case, the residual sodium chloride moiety, which acts as an electrolyte, is essential, while coagulation being added directly as an electrolyte, i.e. the accumulation of the colloidal moiety into a larger aggregate, can be significantly activated.

30 2,000 Area of application 2,100 Prerequisites; The indoor swimming pool selected as a test site is owned by the municipality and open to the public.

2.110 Liquid pressure conditions 35 The stainless steel (V2A) pool has dimensions of approximately 25 x 12 m as the depth increases from approximately 0.9 to 1.8 m. The area is thus about 300 m2, 0 77436 volume about 400 m3.

The recirculation is handled by three pumps operated in parallel and is ensured by a total recirculation of 105 m3 / h with a recirculation time of 4 h for 5 complete cycles of water.

The inflow of purified water takes place in the longitudinal direction; removal takes place from the overflow chute at the top to the equalization tank.

2.120 Water treatment 10 2.121 Implementation of the method

The water purification method is divided into flocculation, filtration, oxidation steps and disinfection.

2.122 Flocking

The flocculation takes place continuously, in which case the flocculant (formerly iron chloride, then aluminum sulphate, later polyaluminium hydroxychloride) is added continuously. Currently, the dosing is 1 ml PAC / m3 recycled water.

2.123 Filtration 20 A multilayer filter (quartz sand and hydroanthracite support) is used. The diameter is 2.0 m, measured from this the filter area is 3.1 m2. Calculated according to water recycling of about 105 m3 / h, the filtration speed is 34 m / h, which corresponds to the swimming hygiene regulation. The backwash 25 takes place automatically on the basis of the pressure difference - control in time.

2.124 Oxidation Step This includes an ozone plant, a reaction and degassing section, and activated carbon filtration.

30 The ozonation capacity is 100 g / h, resp. 1 g / m3 according to water recycling. The reaction time of 1.7 min (in the degassing tank) corresponds approximately to the current perceptions. The ozone leaving is led to an ozone separator. In the next activated carbon filter (filter area 2.5 m3, 35 filtration speed 42 m / h), still dissolved ozone is removed from the water after the degassing step.

2.125 Disinfection

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11 77436 This is ensured by dosing an aqueous solution of granular chlorine. The product is an organochlorine compound (dichlorocyanourate), which is replaced after storage by an inorganic compound (calcium hypo-5 chlorite) to comply with bathing hygiene regulations, according to which dichloroisocyanourate as the sole disinfectant must not be added when the pool size exceeds 130 m2.

To detect the excess disinfectant, the DBD method is used, whereby the separation of free and bound chlorine is possible. The measuring device is a color-metric device with excellent display resolution. Measurements are performed at least three times a day, ie recorded in a diary.

15 During the trial period, the operating controls were refined, i.e. they were carried out by means of notes intended for that purpose.

3,000 Test run 3,100 Prerequisites 20 _3.110 Monitoring

In order to keep all the measures reproducible for their consequences, λ was installed continuously. functional measuring devices for measuring free chlorine, pH and redox potential. Test water for this was taken ’25 before oxidation and chlorination.

Plant-specific measurements and memory-. The inputs were expanded, ie the measurement results of the automatic measuring devices were controlled by confirmed control measurements.

In addition, sampling and extended studies were carried out, paying particular attention to the possible optimization of bathing water quality, in particular by reducing the chlorine content (as a result of the use of the substance) in order to maintain the minimum or maximum values described above.

3.111 Analytical scope Austrian legislation requires a minimum quality assurance of bathing water of 12,77436 (at least as required by law), e.g. a certain minimum number of chemical analyzes to be carried out by the company itself as well as by official controls.

These include at least: pH, chlorine concentration (free-acting and bound-acting according to the DBD method, i.e. diethyl-p-phenylenediamine method), oxidizing agent content (KMnO 4 consumption, redox potential, nitrate content and chloride content).

In this case, the following values are allowed, taking into account the choice of water purification method: pH value 7.0 to 8.3 chlorine, free 0.3 mg / 1 min.

chlorine, bound 0.5 mg / l max.

15 KMnO 4 consumption 3.0 mg / l max. Make-up water redox potential 650 mV min. nitrate 20 mg / l max. make-up chloride chloride 100 mg / 1 max. make-up water 20 For bacteriological reasons, the amount of aerobic bacteria may not exceed 300 / ml; Escherichia coli must not be detectably present in 100 ml.

The studies were oriented under these conditions.

3.200 Operating variables

In order to test the optimal method of addition of the substance, different alternatives were selected in the preliminary tests and attention was also paid to the amount of addition. The following methods of addition and 30 amounts were chosen: 1.) In single increments a) Every 2 days 10 ml b) Daily 1 time 5 1 c) Daily 2 times 5 1 35 2.) Continuously in parallel with the flocculant.

The experiment showed that the effect of the substance was better when added at shorter intervals than at longer intervals.

These data resulted in continuous dosing with a flocculant, which could be reduced by more than 50% to 0.5 ml / m3. In addition, a dosage of 0.6 ml of substance / 1 m3 of circulating water was finally found to be optimal.

For a daily water recirculation of 2400 m3, the addition amount was calculated to be 1.0 L of Polyaluminium Chloride 1.0 (PAC) and 1.5 L of Substance.

4,000 Results 4,100 Analysis values

For evaluation, the values of subheading 3.111 Analytical Scope below were considered, 15 resp, the effect of the substance on them was interpreted: pH: pH at the beginning of the experiment ranged from 7.2 to 7.4. It did not show any other changes during the experiments.

Chlorine, free, effective: the proportion of free, effective 20 chlorine was kept in the experiments with the substance at least between 0.4 and 0.6 mg / l. In this case, it was possible to reach a redox potential of 700 (680 to 710 mV), i.e. to keep it there.

By continuously administering 0.6 ml of substance 25 and 0.4 ml of PAC / 1 m3 in parallel, the redox potential could be increased from 700 to 750 mV during the day. This required a reduction in the addition of downstream chlorine of more than 50% of the initial essential amount and always as long as the value of the redox potential described above could be maintained. Thus, it was possible to maintain a redox potential of 110 mV with 0.20 to 0.25 mg of free chlorine, even during relative overload in the evening hours.

Chlorine, bound; the bound chlorine content of 35 in the plant of this house was low. During the experiments, only small amounts of bound chlorine could be detected, in no case more than 0.1 mg / l.

14 77436 ΚΜηΡ4 consumption: this was between 3-4 mg / l abs during the experiment. and thus lower than the filling water. Even when the chlorine addition to 0.2 mg / l was reduced, there was no change above 4 mg / l and it was 3-4 mg / l throughout 5.

Redox potential: as already described under the heading "chlorine, free-efficient" using the substance, despite a reduction in chlorine dosing of more than 50%, a redox potential of 700-710 mV could be ensured. For further information, reference is made to the heading "chlorine" above.

Nitrate: the nitrate content was in all cases less than 20 mg / l (11 to 19 mg / l) and thus always the required "20 mg / l below make-up water" with a concentration of 6-14 mg / l.

15 Chloride: the value of the make-up water (5-12 mg / l) must not exceed 100 mg / l in accordance with the Bathing Hygiene Act. The values observed during the experiments ranged from 120 to 135 mg / l, exceeding the maximum value (minimum value).

20 Bacteriological studies (orientation, in-house) showed excellent results even at a value of only 0.2 mg / l chlorine and at a load exceeding 50% of the nominal load (88 per 60 persons). The highest amount of aerobic bacteria was 20/1 ml. Escherichia 25 coli, which must not be detectably present in 100 ml, could not be detected in any case.

No additional chemicals and disinfectants, etc. other than those selected were required during the trial period.

30 The substance was tested in a pond. The material prepared according to Example 1 was also used in this experiment.

The free water body where efficiency was tested is an artificially constructed pond located in 35 sparsely built weekend housing estates in Lassee, southern Austria. The east of the pond VII, as it was called, was 300 x 60 m, the maximum depth

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15 77436 about 3 m and thus a volume of 50,000 m3.

The beach and the bottom are not artificially made, however, the retaining walls of most beach plots are close to the beach. The water level is slightly below the 5 adjoining plots. There are fish in the pond; occasionally go swimming.

In recent years, water quality has deteriorated, manifested mainly by turbidity, a decrease in depth of vision to about 30-40 cm, and an additional 10 algal growth (mainly on shore stones) and an unpleasant odor from time to time.

Initially, the pond was treated by spraying 1000 L of material with a pressure sprayer over the water surface. This procedure was repeated three weeks later with 500 L of substance-15 Elia. The amount of substance used was thus about 1,500 1 / 50,000 m3, of which the relative proportion is 30 mg / l.

To evaluate the effect, the following chemical-physical parameters were monitored: temperature, pH, depth of vision, total hardness, carbonate hardness, non-carbonate hardness, potassium permaginate consumption (oxidizability), chloride, nitrate, nitrite, phosphate (total), sulphate iron, oxygen content and oxygen consumption (intermittent). Similarly, the number of bacteria / 1 ml as well as coliforms and Escherichia 25 coli / 100 ml were determined from time to time.

Experiment (A) performed before the first treatment showed the following characteristic values for organic or nutrient loading: KMnO 4 consumption 19 mg / l 30 Nitrate NO3 41 mg / l

Phosphate (P-total) 31 mg / l

Ammonium NH3 0.05 mg / l Visual depth 40 cm

In connection with the first spray (B), new experiments were taken and examined 3 hours, 4 days (C), 3 weeks (D) and 6 weeks (E) after the experiment: 774 36 1 6 (Α) (Β) (C) (D) (Ε) ΚΜηΟ * consumption 19 15 13 11 10

Nitrate Ν03 41 27 20 13 14

Phosphate Ρ (total) 31 27 25 18 19 5 Ammonium ΝΗ3 0.05 0.05 0.05 0.05 0.05 Depth of view 40 40 80 110 120

Oxygen 02 10.5

Oxygen consumption 0.8

Oxygen saturation 9.1 10

Experiment (D) (after three weeks) further determined: bacterial count 875 coliform bacteria 212 15 Escherichia coli 86 From these analytical results it can be seen that the addition of the substance caused a significant improvement in water quality.

Apart from the fact that a visual change in visual depth from 0.4 m to 1.2 m was achieved, both KMnO 4 consumption and also phosphate and nitrate concentrations show a significant decrease, which can be explained by the accumulation of these harmful substances in the flocs formed as described above. , resp, are absorbed.

The reduction in nutrients thus achieved, in this case for phosphates and / or nitrates corresponding to the nutrients in the aquatic environment, thus achieves good conditions for the associated manifestations of algal growth, such as the reduction of reduced visibility depth in a useful manner. Altering some chemical values in parallel with this is not apparent to the visual observer, but provides the analyst with a correspondingly professionally oriented assessment.

Examples of methods according to the invention are given below.

Example 1

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To 77436 390 l of water in a boiler was added 0.6 kg of CaO (quicklime, quicklime) with stirring for 1 h. A further 7 kg of drill flour (analysis sample 1) with a NaCl content of 48% was added. The mixture is then stirred for 5 h. After stirring, 406 l of crude brine (28% NaCl) are added. The resulting mixture was stirred again for 2 h. The pH was then adjusted to the desired final value of 9.85. After sedimentation of the insoluble components for 5-10 h, the solution was decanted.

10 The finished product had the following characteristics:

Appearance: colorless, clear liquid

Odor: odorless

Taste: salty-concentrated 15 Reaction: alkaline, pH 9.85 (undiluted)

Density: 1.13 g / cm 2 20 ° C

Example 2.

195 L of water was added to the vessel. To this amount of water was added 0.6 kg of base / CaO (burnt, slaked-20 tons of lime) for 1 h with stirring. Then, according to a NaCl content, which is basically inversely proportional to the silicate content, 2 to 7 kg of drill flour were added. If the NaCl content of the drill flour was about 20%, 2 kg was added, if it was about 80%, 7 kg of drill flour was added. After the addition of 195 l of water, the resulting mixture was scaled again for 2 h. The pH was then adjusted to the desired final level of 9.5 to 10.5 (if this is not reached, it is adjusted to this value by adding quicklime or hydrochloric acid). After sedimentation of the insoluble constituents 30 for about 5 to 10 hours until the solution was clear, the solution was decanted.

Example 3.

Using the principal procedure of Example 2, 1 kg of a salt extraction residue with a practically zero NaCl content was added to the alkaline solution or slurry (water and quicklime) instead of the drilled flour. After stirring, ί s 7 7 4 3 6 106 L of crude brine containing 28% by weight of NaCl was added and then the procedure of Example 2 was followed.

Example 4.

417 l of water are added to the vessel by switching on the stirrer-5, and to this are added 1 kg of sodium hydroxide solution and 15 kg of the salt deposit extraction residue. The mixture is stirred for 3 h and allowed to stand for 12 h. Then 125 l of crude brine (28 wt%) and a further 1100 l of water are added. The solution is stirred for 0.5 h and allowed to stand for 5-10 h, 10 until the solution is clear. The pH is adjusted to between 9.5 and 11 according to Example 2. Finally, the solution is decanted.

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Claims (6)

77436 A process for the preparation of a liquid substance for improving the quality of contaminated water, in particular swimming pools, natural waters and effluents, characterized in that a ground mixture of clay, common salt and gypsum is added to an aqueous solution or slurry of an inorganic base or slurry by stirring , optionally also 10 crude salt solutions, that the mixture thus obtained is stirred for 2 to 5, preferably 3 h, that the pH of the resulting solution is adjusted to between 7.5 and 10.5, preferably 9.5 to 10.5, if necessary by adding acid or base, and that the solution is separated from the insoluble components. Process according to Claim 1, characterized in that an aqueous solution or slurry having a pH of more than 10, preferably more than 12, is used. Process according to Claim 1 or 2, characterized in that a naturally occurring mixture of clay, common salt and gypsum and / or an extraction residue obtained from such mixtures with a NaCl content of between 20 and 80% by weight is added to the solution. Process according to one of Claims 1 to 3, characterized in that before adjusting the pH to the desired final value, the common salt content of the solution is increased by adding common salt to 14 g of NaCl / 1 l solution. Process according to Claim 4, characterized in that the cooking salt is added in the form of an aqueous solution, e.g. as a crude salt solution, preferably containing 28% NaCl. Process according to Claim 4 or 5, characterized in that, after the addition of the common salt, further water is optionally added to the mixture and that the mixture is stirred for 1 to 4 hours after the addition. ? 0 77436