MXPA98002088A - Chlorides of polyaluminum and chlorosulphates of polyaluminum, methods and composition - Google Patents

Abstract

The present invention is directed to a process for the production of polyaluminium chlorides and polyaluminium chlorosulfates as coagulants in water treatment. In addition, the invention is directed to products made by the described procedures.

Description

POLYALUMINUM CHLORIDE AND POLYALUMIKFIO CHLOROSULPHATES, METHODS AND COMPOSITIONS Field of the Invention The present invention relates to processes for producing polyaluminum chlorides and polyaluminium chlorosulfates. The processes can generate products of a wide range of basicities and which are suitable for use as agents for water purification. BACKGROUND OF THE INVENTION Polyaluminium chlorides and polyaluminium chlorosulfates are compounds used as flocculants and coagulants for water treatment and wastewater. Compared to other inorganic purification agents, these compounds generally work more efficiently, produce less sludge by-products, work better in cold water, sediment faster and lower the water pH in a smaller proportion. The compounds are also used in the production of paper, antiperspirants, food and pharmaceuticals. A number of processes have been designed to produce polyaluminium chloride and polyaluminium chlorosulfates with favorable characteristics for water treatment. For example, U.S. Pat. No. 5,246,686 describes a process wherein basic aluminum chlorosulfate is reacted with an alkaline earth metal compound (eg, calcium carbonate) to produce high basicity polyaluminum chlorosulfates. A disadvantage of this reaction is that it results in the formation of insoluble alkaline earth sulfates (eg gypsum) that must be removed from the product solutions, by procedures such as filtration or centrifugation. This makes the reaction undesirable in high volume industrial operations. Similar problems involving the formation of precipitates have been found in processes comprising the reaction of aluminum sulfate with a slurry of calcium carbonate and calcium chloride (see for example U.S. Patent No. 4,981,673 or U.S. Pat. US No. 5,076,940). A process that prevents the formation of gypsum-type precipitates is described in U.S. Pat. No. 5,348,721. The described method requires the initial production of a polyaluminum chlorosulfate with relatively high basicity (40-50%). This is then reacted with an alkaline earth metal compound (eg, calcium carbonate) and an alkali metal compound (sodium carbonate) at a temperature of 50 to 70 degrees centigrade. Reactions made at lower temperatures (40 degrees Celsius) result in a product that coalesces in a gel. A problem with this procedure is that the generation of C02 can cause processing problems when the reaction is performed on a large scale. However, it seems that this is the only reported process that is capable of producing polyaluminium chlorosulfates with more than 67% basicity and a preparation that is 75.3% basic is described in the patent specification. Due to the chemistry involved, all products are produced using substantial amounts of calcium carbonate. An alternate process is described in U.S. Pat. No. 3,929,666. In this patent, a solution containing sulfate ions is mixed with a solution containing both aluminum ions and halide ions and with a solution containing sodium or potassium aluminate. The reaction is carried out at a temperature of 40 ° C or less and produces a gel that must then be dissolved by raising its temperature between 50 and 80 ° C. Due to the difficulty in efficiently pumping gels from one site to another and due to the problems presented by the gels in terms of mixing and thermal transfer, the process described in this patent is of limited value in large-scale industrial applications. The present invention is directed to a method that avoids many of the problems associated with previously described methods. It can be used to produce compounds with basicities greater than 70% using as starting material, basic aluminum chlorides and basic aluminum chlorosulfates with low basicity (25% or less). The polyaluminium chlorides and polyaluminium chlorosulfates produced are fluid, ie they do not coalesce into a gel, and the formation of calcium sulfate precipitates can be avoided. In addition, they can be produced without the addition of heat, thus preventing the formation of undesirable by-products. As a result, the process is particularly well suited for large-scale industrial applications. In addition, the process allows the formation of products with unique properties that are also part of the invention. Polyaluminium chlorosulfates can be produced that are greater than 75.3% basic and preparations with more than 70% basicity can be produced without substantial amounts of calcium carbonate. In addition, concentrated preparations of polyaluminium chlorides and high alkalinity polyaluminium chlorosulfates containing aluminum may be obtained, generally the form of aluminum which is generally considered the most efficient for removing impurities from water. The present invention is directed to a process for producing polyaluminum chlorides and polyaluminium chlorosulfates, suitable for use as coagulants in water treatment. The first step in the process involves mixing a solution comprising sodium aluminate with a solution already comprising basic aluminum chloride (if the desired product is polyaluminium chloride) or basic aluminum chlorosulfate (if the desired product is polyaluminium chlorosulfate) . It is essential that these solutions are mixed under sufficiently high shear conditions to avoid gel formation and that the reaction temperature is maintained below 50 ° C. When the reaction is carried out under these conditions, a non-viscous milky suspension is produced which will be transparent with time. In an optional second step, the temperature of the milky suspension is gradually increased until a clear product solution is obtained. In preferred embodiments, the reaction between sodium aluminate and either basic aluminum chloride or basic aluminum chlorosulfate is carried out at or below 40 ° C and the mixing occurs in the presence of a velocity gradient of at least 1000 reciprocal seconds. For reactions where the basicity of the product will be 70% less, it is preferable that a small amount, for example less than 1% calcium carbonate is added to the basic aluminum chloride solution or basic aluminum chlorosulfate before mixing with sodium aluminate. The addition of calcium carbonate to reactions that form products with more than 70% basicity is completely optional. It can be added if desired, but its inclusions do not appear to substantially improve the stability of the products. The basic aluminum chloride or basic aluminum chlorosulfate employed as a reagent in the process can be made using a variety of methods well known in the art. The preferred method for producing basic aluminum chloride is to react an aluminum oxide trihydrate with hydrochloric acid or a combination of hydrochloric acid and phosphoric acid. In the case of basic aluminum chlorosulfate, it is preferred that a source of aluminum oxide trihydrate be reacted with hydrochloric acid and sulfuric acid. An optional fourth step can be included in the process wherein polyaluminum chloride or polyaluminum chlorosulfate produced as described above, is employed in a second reaction with sodium aluminate. This stage is particularly useful in cases where very high basicity products are desired. As before, the mixing of reagents is carried out at a sufficiently high shear force to avoid gel formation, preferably in the presence of a velocity gradient of at least 1000 reciprocal seconds. When preparing polyaluminium chlorides of between 50 and 70% basicity, the preparations can be mixed at a temperature below 60 ° C. For products with more than 70% basicity, the mixing should generally be carried out at a temperature higher than 60 ° C, in order to avoid gel formation. However, it is also possible to obtain a product with more than 70% basicity in reactions that are carried out below 60 ° C, by reducing the speed at which sodium aluminate is added to the reaction and by increasing the Shears. The resulting milky suspension can be heated to produce a transparent product or allowed to clear over time without applying additional heat. In addition to being included as a fourth step in the present process, the reaction between polyaluminum chloride or polyaluminium chlorosulfate and sodium aluminate can be used to increase the basicity of polyaluminium chlorides and polyaluminum chlorosulfates made by other processes. In addition to the processes described above, the present invention is directed to the polyaluminium chlorides and polyaluminium chlorosulfates produced by the processes. This includes compositions having polyaluminium chlorosulfates with more than 75.3% basicity and compositions with more than 70% basicity that do not use calcium carbonate or other alkaline earths. The present invention includes concentrated compositions (8% A1203 or greater) of polyaluminum chlorides and polyaluminium chlorosulfates containing Al13 species. These species are detectable by NMR in preparations with approximately 80% basicity or greater. In another aspect, the present invention is directed to a process for producing a coagulant composition, useful for removing impurities from water by mixing a polyaluminum chloride or a polyaluminium chlorosulfate, either with an organic or inorganic salt. The polyaluminum chloride or polyaluminium chlorosulfate should be mixed in an amount such that its final concentration in the coagulating composition is less than about 25% by weight or more than about 75% by weight. Preferred salts are ferric chloride, ferric sulfate, ferrous sulfate, aluminum sulfate, aluminum chloride and quaternary ammonium chlorides. The compositions mixed themselves are also encompassed by the invention, seeing that processes for removing impurities from the water using these compositions. In the latter, the compositions are mixed with water containing impurities, the mixture is allowed to flocculate, and the flocculant is then removed to produce water in which the concentration of impurities has been reduced. Brief Description of the Figures Figure l. Figure 1 shows the NMR spectrum given by the polyaluminum chlorosulfate prepared according to the procedure described in the patent of the E.U.A. No. 3,929,666 (10.5% of A1203 2.8% of S04, 50% basic). The main peak is at 0.3210 ppm. Figure 2. Figure 2 shows the NMR spectrum of polyaluminum chlorosulfate prepared according to the procedure described in Example 6 (10.5% of A1203 50% basic, 2.9% SOJ.The process employs mixing with high shear in order to avoid gel formation The main peak is at 0.193 ppm Figure 3. Figure 3 shows the NMR spectrum obtained from a basic aluminum chlorosulfate preparation made using the procedure in Example 3 (13.4% of A1203, 18% basic and 3.8 % SOJ The main peak is at 0.93 ppm, Figure 4. Figure 4 illustrates the NMR spectrum obtained using commercially available Stern-PAC polyaluminium chlorosulfate The main peak in the Figure is at 0.488 ppm Figure 5. Figure 5 illustrates the NMR spectrum obtained using commercially available Westwood 700S polyaluminium chlorosulfate The main peak in the Figure is 0.477 ppm Figure 6. Figure 6 illustrates the NMR spectrum of polyaluminium chloride Worked according to the procedure described in example 9 (10.5% aluminum oxide, 90% basic). The process uses mixing with high shear in order to avoid gel formation. Note the presence of a peak at 63 ppm. Figure 7. Figure 7 illustrates the NMR spectrum of polyaluminium chlorosulfate according to the procedure described in Example 10 (10.5% A1303, 88% basic and 0.2% SOJ) The procedure employs mixing with high shear in order to avoid The presence of a peak at 63 ppm should be noted Figure 8. Figure 8 illustrates the NMR spectrum obtained using commercially available aluminum hydrochloride (Summit Chemical Co.). ppm Definitions Polyaluminium Chlorides: Polyaluminum Chlorides are products of aluminum hydroxide chloride, A1C1 (0H) _, A1C1. (OH), and A12C1 (0H) S. A representative formula is: Al2Cl6-n (0H) n / where n * 2.7 to 5 for products formed by the procedure described here It is considered that when the products are diluted, polymeric species such as All304 (0H) 24 (H_0) 12 + 7Cl are formed Polyaluminium chlorosulfates: These compounds can be better described by the formula: A l2 (0HnCl (É.n-2k) (S0Jk where n = 2.7 to 5 and is greater than 0 and less than 4.3. The main difference between basic aluminum chlorosulfates and polyaluminium chlorosulfates is the amount of hydroxyl substitution; where n is less than or equal to 1.5 for the former and between 2.7 and 5 for the latter. The polymer species formed before dilution can be expressed as: A11304 (OH) 24 (H20) 12 + 5C1 + S04. Basic aluminum chlorides: These are compounds that have the formula: Al2 (0H) n (Cl) e-n where n is greater than zero and less than or equal to 1.5. It is considered that solutions of these compounds contain: Al (H20) e + 3Cl; Al_ (0H) _ (H_0) ß + 4Cl; and Al (OH) (H20) 5 + 2Cl. Basic aluminum chlorosulfates: These are compounds of the formula: Al2 (0H) D (Cl) (6-n-2IC) (S0Jk where n is greater than zero and less than or equal to 1.5, and where k is greater that zero but less than 0.5 It is considered that solutions of these compounds contain all the compounds present in basic aluminum chloride as well as: A1 (H_0) 6 + C1 + (S0J; Al. (OH). (HaO) ß + 2Cl + (SOJ Percent Basicity: As typically used in the specialty, percentage basicity is defined as (% 0H) (52.91) / (% A1). At a molar level, this can be expressed as ((OH) / (Al) ) / 3 multiplied by 100. In this way Al (OH) (H20) 5 + 2C1 has the basicity of 33% Basicities discussed in the text in connection with products made by the present process, for example products described in the examples, reflect formula basicities based on hydroxide content.It has been discovered that these products will hydrolyze to form species of higher basicity than or formulated. The degree of hydrolysis is inversely proportional to concentration and directly proportional to the basicity of the formula. In this way, the product of example 7 while being formulated as 70% basic, will be analyzed as 79% basic. High Shear Mixing: As used herein, the term "high shear mixing" refers to combining solutions under conditions that create a sufficiently high shear force to avoid gel formation. The shear force can be created by one or more homogenizers, mixers, centrifugal pumps or pressurized nozzles designed to forcefully combine solutions. In general, mixing should be carried out under conditions sufficient to create a velocity gradient of 1000 reciprocal seconds or greater.

Aluminum Salt Concentration of Reaction Products: The concentration of aluminum salt that is established as present in a reaction product refers to the amount of aluminum oxide that would have been necessary to produce the product. In this way, products that have a certain percentage of A1203 are described even though the aluminum oxide may in fact not be present in the product. This is common practice in the art and allows products to be compared based on their chemistry. Moist Filter Cake: Moist filter cake is a product purified by bauxite. It is produced by digesting bauxite in sodium hydroxide and then precipitating aluminum oxide trihydrate (also known as gibbsite). Typically, the filter cake contains 5 to 10% free moisture. Detailed Description of the Invention i. General of the Process The present invention is directed to a process for producing polyaluminum chloride or polyaluminium chlorosulfate. In total, it involves either producing basic aluminum chloride or basic aluminum chlorosulfate and then reacting this compound with a solution of sodium aluminate. A novel feature is that the mixing of sodium aluminate, either with basic aluminum chloride or basic aluminum chlorosulfate, is carried out under high shear conditions in order to avoid the formation of a gel. The product solution is a milky suspension that can be easily pumped through machinery designed for high volume production. This solution can optionally be heated to remove its opacity and produce a transparent fluid containing polyaluminum chlorides or polyaluminium chlorosulfates suitable for use in water treatment. Alternatively, the solution of milky products can simply be left to rinse without applying additional heat. Typically, the process described herein will be employed to produce aluminum chlorosulfates formulated for 40% or greater than 80% basicity and which can be used immediately or stored for a period of at least 7 months without formation of significant precipitate. Polyaluminum chlorides are unstable when they have basicities of 30% to 75%, that is, they tend to form a precipitate with time. Thus, if a polyaluminium chloride coagulant is desired in the basic range of 20 to 45%, the addition of phosphoric acid should be considered. For basicities of 45% and higher, it will generally be preferable to use the process to produce polyaluminium chlorosulfates.

Optionally, the present invention may include in the step where the clear product solution containing either polyaluminium chloride or polyaluminum chlorosulfate is used in another reaction with sodium aluminate. This reaction provides a means for further increasing the basicity of reaction products and can also be employed independently of other process steps. In this way, the basicity of polyaluminium chlorides and polyaluminium chlorosulfates can be increased independently of the specific process by which these compounds are made. II. The Production of Basic Aluminum Chloride or Basic Aluminum Chlorosulfate Suitable for the Present Procedure Basic aluminum chloride or basic aluminum chlorosulfate can be produced by a wide variety of different processes. Typical methods for producing these compounds include: a) decomposing metallic aluminum with hydrochloric acid; b) exchange hydroxide ions with chloride ions by passing a solution of aluminum chloride through an ion exchanger; c) reacting aluminum hydroxide with hydrochloric acid or a combination of hydrochloric acid and sulfuric acid; d) neutralizing a solution of aluminum chloride with an alkali; and e) reacting alumina trihydrate with hydrochloric acid under pressure. A. Preferred Method for Producing Basic Aluminum Chloride Although any of the above procedures may be employed to produce material suitable for the present process, the preferred method for producing basic aluminum chloride is to react a source of aluminum oxide trihydrate with hydrochloric acid. The objective of this reaction is to produce a product that is between about 5% and about 25% basic. It is desirable to make the compound as basic as is economically feasible, since basic aluminum chlorides and basic aluminum chlorosulfates with low basicity require more sodium aluminate to produce a desired polyaluminum chlorosulfate or polyaluminum chloride product. Since sodium aluminate has sodium hydroxide associated with it, increasing its amount means that more salt will be generated when the solutions are neutralized and that the total process will be more expensive. Basic aluminum chlorosulfate or basic aluminum chloride of higher basicity can be made by increasing the amount of aluminum oxide trihydrate using the reaction, reducing the amount of water in the reaction, maintaining a higher reaction temperature, or by allowing the batch to react for more time Up to 4% phosphoric acid can be added to prevent crystallization with products of lower basicity or higher concentration. Small amounts of phosphoric acid can also be added to products of higher basicity to increase the particle size of the flocs, when the polyaluminium chloride is used as a flocculant. In general, the amount of phosphoric acid should not exceed 0.5% in products with more than 75% basic or the product will be too viscous to handle. The preferred reaction can be carried out to produce basic aluminum chloride from 5% to 25% basicity, using wet filter cake of 50% to 65% aluminum oxide. The wet filter cake is reacted in a solution of 30% to 35% hydrochloric acid while maintaining the reaction temperature between 60 and 115 ° C. Typically, 5 moles of hydrochloric acid are added per mole of aluminum oxide, to produce basic aluminum chloride. To make basic aluminum chlorosulfate, 4 or 5 moles of hydrochloric acid and 0.02 to 0.5 moles of sulfuric acid will typically be used per mole of aluminum oxide. Increasing the time allowed for the reaction to proceed increases the basicity of the product. In general, reactions between 4 and 24 hours have been found to produce a convenient product. The reaction can be accelerated by grinding the filter cake to smaller particle sizes, increasing the concentration of hydrochloric acid or using high pressures and temperatures. However, these methods for accelerating reactions significantly increase the cost of production and are preferably avoided. B. Preferred Method for Producing Basic Aluminum Chlorosulfate The preferred method for producing basic aluminum chlorosulfate is similar to the method described above for basic aluminum chloride, except that sulfuric acid is substituted stoichiometrically by hydrochloric acid. The amount of sulfuric acid to be used depends on the desired amount of sulfate in the final polyaluminium chlorosulfate product. Specifically, the amount of sulfate in the product may not exceed the amount in the equation:% sulfate = 10.5 - (((0.125 x basic% x Al3OJ / 10.5) If the percent of sulfate in the above equation exceeds, the Aluminum chlorosulfate will be gel type and difficult to handle.The optimum percentage of sulfate that should be present in a polyaluminium chlorosulfate for peak effectiveness as a flocculant in water treatment, will vary according to the specific characteristics of the water. exceed the percentage indicated by the above equation, the sulfate concentration can be adjusted to produce the optimum product for a given application.In general, the percentage of sulfate in basic aluminum chlorosulfate should be between zero and 8% to give polyaluminium chlorosulfate between 0 and 6% Typical formulations are given below in examples 2, 3 and 4. III. Reaction of Chloride or Chlorosulfate Basic Aluminum with Sodium Aluminate The basic aluminum chloride or basic aluminum chlorosulfate described above is reacted with a solution of sodium aluminate. For reactions where the product will have a basicity of 70% less, it is preferred that a small amount of an alkaline earth metal compound (eg, 0% calcium carbonate) is added to the solution of basic aluminum chloride or chlorine sulfate of basic aluminum to serve as a stabilizer before the addition of sodium aluminate. Failure to add the stabilizer can cause product solutions to have a slight turbidity or form small amounts of precipitate. In general, the lower the basicity of the product, the more convenient is the addition of the stabilizer. For products where the basicity is greater than 60%, the calcium carbonate will not substantially improve the stability. However, it will not adversely affect the product and may be added if desired. The amount of sodium aluminate to be combined with basic aluminum chloride or basic aluminum chlorosulfate will depend on the desired basicity of the end point and can be determined according to the following equation, where all percentages are expressed as such, without dividing by 100. (for example 15% is expressed as 15, not 0.15):% BAC or% BACS (SAAxPAxPB - SAOHxlOOxPA - SAAxCCx33.98) (BBxBAxSAA / 100 - BBxSAOH) where: BAC = basic aluminum chloride BACS = basic aluminum chlorosulfate SAA = percent of A1203 in sodium aluminate SAN = percent Na.O in sodium aluminate SAOH = percent of hydroxide in sodium aluminate SAA + (SAN x 0.54865) PA = desired percentage of Al203 in polyaluminum chloride or aluminum chlorosulfate .

PB = desired basicity in polyaluminum chloride or aluminum chlorosulfate. CC = desired percent of desired CaC03 in polyaluminium chloride or polyaluminium chlorosulfate. BB = basicity per cent in basic aluminum chloride or basic aluminum chlorosulfate. BA percent of A1203 in basic aluminum chloride or basic aluminum chlorosulfate. Similarly, the amount of sodium aluminate necessary to give the proper formulation can be determined by using the following equation:% sodium aluminate = (PA x PB - B x BB x BA / 100 - CC x 0.3398) / SAOH where B = percent of basic aluminum chloride or basic aluminum chlorosulfate as determined by the above equation. Water should be added to the reaction in an amount that is determined by the final desired percentage of Al2Oj. For example, if the percentage of aluminum oxide in the reagents was 20% and it is desired that the final product have a concentration of aluminum oxide of 10%, then the mass of water added should be equal to the total mass of the reagents In order to reduce the amount of heat generated during reactions, it is preferred that cold water is added to the sodium aluminate and that the resulting solution is then mixed with the solution containing basic aluminum chloride or basic aluminum chlorosulfate. The temperature of the reaction should be kept below 50 ° C and preferably below 40 ° C. If temperatures above 50 ° C are used when mixing, species not suitable for water treatment will be formed. In addition, the product will tend to have shelf life or reduced storage. An essential aspect of the reaction described above is that the sodium aluminate solution and the solution containing basic aluminum chloride or basic aluminum chlorosulfate are combined under high shear mixing conditions. Mixing with high shear is a procedure that can be achieved using a wide variety of different devices. For example, this mixing can be achieved by using a mixer or homogenizer (see for example U.S. Patent No. 5,149,400) with centrifugal pumps, or through the use of machinery forcing solution streams together at high pressures (see for example patent of the US No. 3,833,718). Mathematically, mixing with high shear can be expressed in terms of fluid shear velocity, which is defined as a velocity gradient: dy = (peripheral velocity) meters / seconds (ft / sec). dy (impeller space) meters (ft) and having reciprocal time units, ie seconds ~ l (see Oldshue, Fluid Mixing Technology, McGraw-Hill, page 24 (1983)). Speed gradients of 1000 reciprocal seconds or more are generally considered to be high shear mixing conditions. The preferred means of mixing are through the use of a centrifugal pump. For example, a person practicing the invention can employ a centrifugal pump with a diameter of 5.1 cm (2") of 15 hp, with a 25.4 cm (10") impeller rotating at 1200 rpm (see for example model 3196 prepared by MTX by Goulds Pumps Inc., Seneca Falls New York). The velocity gradient created by this pump would be: dy * (52.4 ft / sec x (l2"/ ft) = (1597 cm / sec) = 1676.8 sec'1 d (.375") (0.9525 cm) Typically, the expense of material flow through the pump should be between 189 and 946 liters (50 and 250 gallons) per minute. The faster the mixture circulates through the pump, the less total shear will the mixture experience. In this way the total shear can be increased by partially closing a flow valve, to reduce the flow rate. It may also be convenient to include one or more additional centrifugal pumps to recirculate the mixture and add additional shear to the process. For example, high shear conditions can be generated using a commercially available 15 hp centrifugal pump with 5.1 cm (2") diameter with a 13.3 cm (51/4") impeller rotating at 3500 rpm. This can create a speed gradient of more than 2500 reciprocal seconds, d (80.0, ft / sec x (l2"/ ft) = (2438.4 cm / sec) = 2560 sec" 1 dy (.375") (0.9525 cm) As a comparison, a batch would be produced in a conventional reactor using a good agitator and the process described in US Patent No. 3,929,666, very little shear would be present, for example, if we consider the following typical parameters: 3407 liters (900 gallons) of material in a conventional reactor of 3785 liters (1000 gallons); a mixing blade with a diameter of 74.9 cm (29.5") a space between blade and deflector of 13.3 cm (5.25") and at a rotor speed of 100 rpm, then the peripheral speed of the agitator would be 396.12 m / seconds (13 ft / sec) and the velocity gradient is as follows:? _y = (13.0 ft / sec x (12"/ ft) = (396.2 cm / sec) = 29.7 sec" 1 dy (5.25") (13.3 cm) In general, it is preferred that the solutions in the present process be mixed under velocity gradients that are as high as practically achieved, using the available equipment and taking into account the desired reaction temperature. For small-scale preparations, mixing can be accomplished using a mixer or homogenizer For large scale preparations, it can be mixed with high shear using centrifugal pumps or with in-line homogenization machines Mixing solutions under the conditions described above is necessary to avoid gel formation and results in a non-viscous suspension. It is considered that beneficial effects of mixing with high shear result by elimination of heterogeneities of local concentration created when the solution is combined and from the disintegration of gelatinous particles before coalescing. Unlike a gel, the suspension formed in the present process can easily be heated, agitated, pumped or cooled. Any type of commercially available sodium aluminate is acceptable for use in producing polyaluminum chloride or polyaluminium chlorosulfate. In general, sodium aluminates of high molar ratio produce more salt by-product while sodium aluminates of lower molar ratio can be more difficult to handle. Satisfactory products have been found that can be made using sodium aluminates with molar proportions, ie Na20 / Al203, from 1.15 to 2.0. Other hybrid sodium aluminates can also be used. Sodium silicate may be present up to 10% SiO2. Aluminate potassium can be substituted for any portion of sodium aluminate in an equivalent molar base. Using the procedure discussed above, polyaluminum chlorides or polyaluminium chlorosulfates can be made in concentrations of 17% aluminum oxide or higher. At concentrations above 17%, the sodium chloride by-product can be removed by filtration. Typical reactions designed to produce polyaluminium chlorides are given below in Examples 5 and 8 and two typical formulations employed in producing polyaluminum chlorosulfates are provided in Examples 6 and 7. IV. Clarification of Polyaluminium Chloride or Polyaluminium Chlorosulfate Solutions. The reaction between sodium aluminate and basic aluminum chloride or basic aluminum chlorosulfate results in the formation of a non-viscous, milky suspension. Optionally in a second stage of the process, the solution can be heated until the milky is clarified. The time needed to achieve clarification can be reduced by reducing the temperature at which basic aluminum chloride or basic aluminum chlorosulfate is reacted with sodium aluminate, decreasing the A1203 concentration in the product, or increasing the amount of shear during mixing. . Too fast heating will generate products that perform efficiently or become unstable. In this way, the heating process should be carried out in a way where the temperature through the solution increases gradually more evenly as possible. In general, products with higher basicity take longer to clarify than products with lower basicity. For basicities greater than 80%, it will typically be necessary to heat product solutions up to 85 ° C. Basicities of 65 to 80% generally require temperatures between 30 and 80 ° C. V. Increase the Basicity of Polyaluminium Chlorides or Polyaluminium Chlorosulfates Carry out a Second Reaction with Sodium Aluminate.

Optionally, a second region can be carried out using sodium aluminate to further increase the basicity of the products. If processing problems are encountered when attempting to make products of high basicity and / or high sulfate content, these can usually be avoided by producing polyaluminium chloride or polyaluminium chlorosulfate of at least 45% basicity, using the procedure above and then adding a Sodium aluminate solution under mixed conditions with high shear. In order to avoid gel formation for products with basicities greater than 70%, the reaction temperature should generally be maintained above 60 ° C, although it is also possible to avoid gel formation by reducing the speed at which sodium aluminate is added. to the reaction and increase the shear force of mixing. For products with a basicity lower than 70%, any suitable temperature below 75 ° C can be used. As before, it is based the amount of aggregate aluminate will be determined in the desired basicity of the final product and can be determined as described in the equation set forth above. Water may also be included in the reaction to adjust the final concentration of A1303. It is preferred that water be added to sodium aluminate, before mixing with the solution containing polyaluminum chloride or polyaluminium chlorosulfate. After this reaction, the product solution should be allowed to sit for a sufficient period of time to allow it to clear, typically less than a day or so. Optionally, heat may be applied to reduce the time needed to clarify the solution. Typical formulations demonstrating the reaction are given in Examples 9 and 10. The reaction with sodium aluminate can also be used to increase the basicity of polyaluminum chlorides and polyaluminium chlorosulfates made by procedures other than the procedure described in Sections III and IV. . In this manner, polyaluminium chlorides and polyaluminium chlorosulfates produced by any process can serve as reactants and be mixed with sodium aluminate under high shear conditions. The reaction will then proceed exactly in the same way as discussed above. VT Properties of Polyaluminium Chlorides and Polyaluminum chlorosulfates prepared by the present methods. The polyaluminum chloride and polyaluminium chlorosulfate preparations made by the present methods have several unusual characteristics that separate them from other similar products. First, polyaluminum chlorosulfates which are unique in terms of their basicity, greater than 75.3% can be produced. In addition, it is possible to produce polyaluminum chlorosulfate preparations with a basicity greater than 70%, which do not contain calcium carbonate or other alkaline earth metals. Although the described methods to produce polyaluminium chlorosulfates with greater than 70% basicity, it sometimes includes the addition of calcium carbonate, this is totally optional and a final product can be produced in its absence that is stable and suitable for water treatment. In addition, the aluminum chlorides and high basicity polyaluminium chlorosulfates prepared by the methods described contain, in their concentrated state, polymeric species not present in similar preparations. Specifically, preparations of polyaluminum chloride with 8% aluminum oxide or greater and having a basicity of about 8% or greater contain A11304 (0H) 24 (H20) 12 + 7C1, As discussed in Example 12, Al13 it can be detected in high basicity products by NMR. Similarly, polyaluminium chlorosulfate preparations with aluminum oxide at 8% or higher contain A11304 (OH) 24 (H_0) 12 + 5C1 + SO,. Polymeric species containing Al13 are considered those that are most efficient to precipitate impurities from the water. Although these species are present in diluted solutions, have not been previously submitted in concentrated preparations, either polyaluminum chlorides or polyaluminium chlorosulfates. VII. Use of Polyaluminium Chlorides and Polyaluminium Chlorosulfates Produced by the Present Process The polyaluminium chlorides and polyaluminium chlorosulfates prepared by the methods discussed above are effective in removing water impurities. As discussed in Example 13, these products consistently outperform similar products made by other processes. The products can be stored for long periods of time without losing their effectiveness, embarking to water treatment plants and then used either directly or after dilution. In addition, it has been discovered that the polyaluminium chloride and polyaluminium chlorosulfate products of the present invention can be used in conjunction with other commercially available coagulants to improve overall performance. Specifically, polyaluminum chlorides or polyaluminium chlorosulfates can be used together with ferric chloride, ferric sulfate, ferrous sulfate, aluminum sulfate, aluminum chloride, epiamines or quaternary ammonium chlorides.

The polyaluminium chlorides and polyaluminium chlorosulfates can be mixed with the coagulants previously noted and maintain effectiveness and stability for a period of at least one month. Although the organic polymers can be mixed in any ratio, the inorganic salts can only be mixed with up to 25% by weight of polyaluminum chloride or polyaluminium chlorosulfate or alternatively with more than 75% by weight of polyaluminum chloride or polyaluminium chlorosulfate. The addition of polyaluminium chlorides or polyaluminium chlorosulfates to coagulants such as those previously noted increases the particle size of flocs formed during coagulation. The addition may now allow the dose of coagulant necessary to achieve a desired level of coagulation to be reduced (see Example 14) thereby reducing the extent to which the pH is abated and decreasing the amount of coagulant sludge formed during the procedure . The examples below are for illustrative purposes only and are not intended to limit the scope of the invention. EXAMPLES Example 1: Production of Basic Aluminum Chloride (First Example) 10,762 kg of wet filter cake (59% of Al.OJ is mixed with 34,599 kg of hydrochloric acid (31.5%) and the mixture is allowed to react for 20 hours at 115 ° C. This produces 45,081 kg of basic aluminum chloride (13.6% of A1303, 20.6% basic) The basic aluminum chloride produced by the reaction can be used in the subsequent steps of the process to produce polyaluminium chloride with 10.5% of A1203, and 83% basicity Example 2: Production of Basic Aluminum Chlorosulfate (First Example) 10.762 kg of wet filter cake (50% Al2OJ, mixed with 27.433 kg of hydrochloric acid (31.5%) 2.377 kg of sulfuric acid (93.5%) and 2,972 kg of water The reaction is continued for 12 hours at 115 ° C to produce 44,941 kg of basic aluminum chlorosulfate (13.4% A1203, 18.0% basic, 4.9% SOJ) This formulation of basic aluminum chlorosulfate can be used in stages d and subsequent reaction of the process to produce polyaluminium chlorosulfate with 10.5% with A1203, and 2.9% of SO4 and 50% basicity. Example 3: Production of Basic Aluminum Chlorosulfate (Second Example) 10,762 kg of wet filter cake (59% of Al203) is mixed with 30,449 kg of hydrochloric acid (31.5%), 1,843 kg of sulfuric acid (93.5%) and 2,303 kg of water. The reaction is carried out for 12 hours at 115 ° C to produce 44,941 kg of basic aluminum chlorosulfate which is 13.4% of A1203, 18.0% basic, 3.8% of S04. The formulation can be used to produce polyaluminium chlorosulfate of 10.5% A1203, and 1.7% S04 and 70% basicity. Example 4: Production of Basic Aluminum Chlorosulfate (Third Example) 10,762 kg of wet filter cake (59% of Als03) is mixed with 34,057 kg of hydrochloric acid (31.5%), 243 kg of sulfuric acid (93.5%) and 297 kg of water. The reaction is carried out for 12 hours at 115 ° C to produce 44,941 kg of basic aluminum chlorosulfate which is 13.4% of A1203, 18.0% basic, 0.5% of S04. This formulation can be used to produce polyaluminum clsrosulfate of 10.5% A1203, 80% basicity, and 0.2% S04. Alternatively, a product that is 10.5% of A1203, 50% basic, and 0.3% SO, can be made. Example 5: Reaction of Sodium Aluminate with Basic Aluminum Chloride 7,598 kg of sodium aluminate (25.5% of A1203, . 0% Na20, 1.29 molar ratio) is mixed with 24.164 kg of water and then combined under high shear mixing conditions with 45.081 kg of basic aluminum chloride (13.6% aluminum oxide, 20.6% basic). The temperature during the reaction is kept below 40 ° C. The reaction results in the formation of 76.843 kg of polyaluminum chloride (10.5% A1203, 51% basic). Example 6: Reaction of Sodium Aluminate with Basic Aluminum Chlorosulphate 44,941 kg of basic aluminum chlorosulfate (13.4% of A1203, 18.0% basic, 4.9% of SOJ is mixed with 285 kg of calcium carbonate, 7.751 kg of sodium aluminate (25.5% of A1203, 20.0% of Na.O, 1.29 molar ratio) are mixed separately with 24.164 kg of water. The diluted solution of sodium aluminate is mixed under high shear conditions with the calcium carbonate / basic aluminum chlorosulfate solution to form 76,089 kg of polyaluminum slorosulfate (10.5% A1203, 50% basic 2.9% SOJ. Reaction is maintained below 40 ° C. Example 7: Reaction of Sodium Aluminate with Basic Aluminum Chlorosulfate (Second Example) 44,941 kg of basic aluminum chlorosulfate (13.4% of A1203, 18.0% basic, 3.8% sulfate) it is combined with 362 calcium carbonate, separately 16,155 kg of sodium aluminate (25.5% of A1203, 20.0% of sodium oxide, 1. 29 in molar proportion) is combined with 35,288 kg of water.

The diluted sodium aluminate solution is then combined under high shear mixing conditions with the calcium carbonate / basic aluminum chlorosulfate solution to form 96.586 kg of polyaluminium chlorosulfate (10.5% Al_03, 79% basic, 1.7% SW,). Example 8: Reaction of Sodium Aluminate with Basic Aluminum Chloride 45,081 kg of basic aluminum chloride made according to Example 1, are mixed with 9,465 kg of sodium aluminate solution (25.5% of A1203, 19.7% of Na. O, 1.27 molar proportion) and 2,824 kg of water through a high shear mixing pump at 30 ° C. The solution is gradually heated by recycling material through a heat exchanger. After the mixture reaches a temperature of 65 ° C, it acquires the appearance of a transparent solution. At this point, 13,428 kg of sodium aluminate solution (25.5% of A1203, 19.7% of Na.O, 1.27 molar ratio) is added slowly to the mixture proportionally together with 4.006 kg of water. Mixing again is carried out using the high shear mixing pump and the addition is carried out for a period of approximately two hours. During this time, the solution is also gradually heated to 80 ° C. This temperature is then maintained for an additional hour to give a clear solution containing 74.801 kg of polyaluminum chloride (16% Al203, 783% basicity).

Example 9: Reacting Polyaluminium Chloride with Sodium Aluminate The procedure described above is used to produce polyaluminum chloride (10.5% A1203, 51% basic) which will serve as reagent. 17,394 of sodium aluminate (25.5% of A1203, 20% of Na.O, 1.29 of molar ratio) is combined with 24.848 of water and the solution thus formed is combined under high shear mixing conditions with 76.843 kg of the chloride reagent. polyaluminium to form 119,085 kg of product polyaluminium chloride (10.5% aluminum oxide, 90% basic). After the solution of basic polyaluminium chlorine products has formed, it can be clarified by gradually bringing its temperature to about 95 ° C. Example 10: Reacting Polyaluminium Chloride with Sodium Aluminate Using the procedures described above, polyaluminium chlorosulfate (10.5% A1203, 51% basic, 0.3% SOJ in a manner that will serve as reagent, 14,940 kg of sodium aluminate is prepared. (25.5% of A1203, 20% of Na20, 1.29 molar ratio) is combined with 21.344 kg of water.The sodium aluminate solution is then combined with 76.233 kg of basic polyaluminium chlorosulfate reagent under mixed conditions with high shear for produce 112,517 kg of polyaluminium chlorosulfate product (10.5% of A1203, 88% basic, 0.2% SOJ.) The product solution is clarified by gradually increasing its temperature, for example over a period of approximately 30 minutes Example ll: Detailed Example of the Process to Produce Polyaluminium Chlorosulfate 15,903 kg hydrochloric acid, 1,352 kg water and 1, 761 kg of sulfuric acid to 93.5%, are added to a steel reactor coated with rubber, lined with bricks, with a capacity of 37,850 liters (10,000 gallons) equipped with agitator and vapor scrubber. While the solution is stirred, 9,869 kg of aluminum oxide filter cake (59% of A1.0J are added in such a way that a sludge is kept in. The mixture is recycled through a heat exchanger to raise its temperature to 60 °. C. Although the application of external heat is stopped at this point, the isothermal reaction that forms aluminum chlorosulfate continues to raise the temperature of the lot.Additional 15,903 kg of hydrochloric acid to 31.5% are then added to the batch in such a way that the temperature Do not exceed 90 ° C or drop below 60 ° C. If the temperature is allowed to exceed 90 ° C at this time, there is a risk that the batch will separate due to evaporation of the reactor. ° C, the batch may require additional heating to continue the reaction.

At some point during the addition of hydrochloric acid, the batch temperature begins to reduce. This occurs because the endothermic reaction of aluminum chlorosulfate with aluminum oxide trihydrate which forms basic aluminum chloride or basic aluminum chlorosulfate begins to absorb heat from the reactor. Once this occurs, the operation of the heat exchanger is resumed in order to maintain the temperature of the batch just below boiling, 115 ° C. The reactor is maintained at this temperature for 8 hours to produce basic aluminum chlorosulfate having the following analysis: 12.5% A1203; 3.6% of S04; 1.0% OH; 8.0% basicity; 21.8% chloride. The basic aluminum chlorosulfate solution is cooled by the heat exchanger until the temperature reaches 30 ° C. At this point, 364 kg of calcium carbonate is added to the reactor. The unreacted aluminum oxide trihydrate is allowed to settle to the bottom of the reactor for approximately one hour. At the end of this time, the decanted solution is pumped to a holding tank. A 41% sodium aluminate solution is injected at a rate of approximately 9.8 liters (2.6 gallons) per minute into a pipeline containing water that circulates at a rate of approximately 33.7 liters (8.9 gallons) per minute. This mixture is then injected into a pipe that recirculates basic aluminum chlorosulfate at a flow rate of approximately 1,060 liters (280 gallons) per minute. The combined mixture is then immediately sheared as it is pumped through a 20 hp centrifugal pump with a 15.3 cm (6") diameter with a 15.4 cm (6 1/16") impeller rotating at 3,500 rpm. After leaving the pump, the mixture circulates through a cooling heat exchanger and then back to the tank. When the procedure is complete, the following has been added to the holding tank: 44,788 kg of basic aluminum chlorosulfate; 17,755 kg of 41% sodium aluminate (25.9% of A1203, 20.2% of Na.O); and 34,368 kg of water. The above procedure results in a milky, non-viscous white suspension, which gradually lightens in a day. The product produced is polyaluminium chlorosulfate which is 79% basic and which has 10.5% A1203 and 1.7% SO. Example 12: NMR Analysis of Polyaluminium Chloride and Polyaluminium Chlorosulfate Preparations NMR spectra were obtained for preparations made by the methods described above and compared with the spectra for similar, commercially available products. The results suggest that as the basicity of the products increases, the proton Al moves upwards in frequency. For example, basic aluminum chloride prepared according to the procedure described in example 3 (13.4% Al20j, 18.0% basic, 3.8% SOJ is found to have its peak 0.93 ppm (Figure 3) while polyaluminium chlorosulfate made according to Example 6 above (50% basic) has its peak at 0.193 (Figure 2) Polyaluminum chlorosulfate made according to the procedure described in US Patent No. 3,929,666 (10.5% A1203, 2.8% of S04, 50% basic) gave a spectrum (Figure 1) which appears to be essentially identical to the spectrum of the product made according to Example 6 above (polyaluminum chlorosulfate: 10.5% A1203, 80% basic, 0.2% SOJ. However, the spectrum for the product of Example 6 differs significantly from two other products having similar basicities and sulfate contents Specifically, Stern-PAC aluminum chlorosulfate has its peak at 0.488 ppm (Figure 4) and poly chlorosulfate. Aluminum Westwood 700S has its peak at 0.477 ppm (Figure 5). When the preparations of high basicity were examined, dramatically altered results were observed. NMR spectra for the product of Example 9 (polyaluminum chloride: 10.5% aluminum oxide, 83% basic) and for the product of Example 10 (polyaluminum chlorosulfate: 10.5% A130380% basic 0.2% SOJ is illustrated in Figures 6 and 7, respectively. These spectra show a transparent peak at approximately 63 ppm, indicating the presence of an Al13 polymer species that is not present in any of the products of lower basicity, and that is also not present in commercially available aluminum chlorohydrate (Summit Chemical Co.) , Figure 8. In this manner, concentrated preparations of polyaluminium chloride and polyaluminium chlorosulfate made by the present process contain the specific aluminum species that are considered the most efficient to remove impurities from the water. Although these species are considered to be formed in diluted solutions, they have not been found in concentrated stable solutions (greater than 8% of A120J either polyaluminum chloride or polyaluminum chlorosulfate) Example 13: Comparison of Flocculants Polyaluminium chlorides and chlorosulfates polyaluminium prepared by the methods described herein, were examined for their ability to serve as water purification agents and compared with commercially available preparations.Experiments were carried out using water from 4 different rivers and a lake. made using the test method commonly used by the municipality from which the water is collected, tests were performed using 1000 ml of raw water on a Phipps &; Bird with products tested at equal aluminum oxide dosages. After performing the procedure dictated by the appropriate municipality, turbidity supernatants were evaluated using a Hach turbidimeter. The turbidity results are illustrated in Table 1. The abbreviation "PAC" in the table represents polyaluminum chloride and "PACS" represents polyaluminium chlorosulfate. The percentages refer to the percentage basicity and the flocculants prepared according to the present description are identified by the specific examples that describe their method of preparation. An examination of the results illustrated in the table indicates that products made according to the methods described herein are effective at water purifying agents. They outperform the competitive products tested with all tested water samples. Table # 1: Turbide2 Study Rio1 Rio2 Rio1 Monongahela Potomac Swimming Raw Water 5.7 25 2.99 Table # 1: Turbidity Study (cont.) RÍO1 Río2 RÍO3 Monongahela Potomac Swimming 50% PACS (Example 6) 1.2 1.86 70% PACS (Example 7) 0.2 4.4 0.86 83% PAC (Example 9) 80% PAC (Example 10) Stern-PAC 1.1 Ultra-Floc 7.6 Westwood 700S 2.05 Aluminum Hydrochloride Table # 1: Turbidity Study (cont.) River * Lake Pelaware Erie5 Raw Water 1.9 0.96 50% PACS (Example 6) 70% PACS (Example 7) 0.39 Table # l: Turbidity Study (cont.) Rio4 Delaware Lake Eries 83% PAC (Example 9.}. 0.86 0.36 80% PAC (Example 10) 0.13 0.31 Stern-PAC 0.42 Ultra-Floc Westwood 700S Aluminum Hydrochloride 1.39 Rio Monongahela Study1: 3.1 ppm A1_03 per flocculant; pH = 6.9; procedure: rapid mixing for one minute at 100 rpm, mixed flocculated for 5 minutes at 60 rpm, mixed flocculated per minute at 40 rpm, mixed flocculated for 5 minutes at 20 rpm Potomac Rio2 Study: 5 ppm of A1203 for each flocculant, pH = 7.8, procedure: rapid mixing for 30 seconds at 100 rpm, mixed flocculated for 2 minutes at 50 rpm, mixed flocculated for 2 minutes at 20 rpm, allowed to settle for 5 minutes. ppm of A1203 for each flocculant, pH = 6.9, procedure: rapid mixing for 15 s seconds at 100 rpm, mixed flocculated for 20 minutes at 20 rpm. River4 Delaware Study: 2.2 ppm A1203 per flocculant; pH = 6.8; procedure: rapid mixing for one minute at 100 rpm, mixing flocculated for 30 seconds at 5 rpm. Lake Erie5 study: 2 ppm A1_0 for each flocculant; pH = 8.0; procedure: rapid mixing for one minute at 100 rpm, mixed flocculated for 10 minutes at 30 rpm, let it settle for 10 minutes. Example 14: Coagulation using Aluminum Mixed Chlorosulfate / Aluminum Sulfate 15 grams of the product of Example 7 are mixed with 85 grams of liquid aluminum sulfate (8% aluminum oxide) and 5 grams of water. The resulting product was tested in a jar for its effectiveness as a coagulant and the results were compared with the coagulation performed with aluminum sulfate alone (8% aluminum oxide). It was found that the mixed product only requires approximately 50% of the aluminum sulfate dose to achieve the same turbidity as when the aluminum sulfate was used alone. Example 15: Production of Basic Aluminum Chloride (Second Example) 2,557 kg of wet filter cake (61% of A1_0J is mixed with 8.549 kg of hydrochloric acid (32.7%), 160 of phosphoric acid (83.8%) and 1.731 kg of water The mixture is allowed to react for 8 hours at a temperature of 110 ° C. This produces 12,793 kg of basic aluminum chloride (11.0% of A1203, 9.8 basic) .The basic aluminum chloride thus produced can be used in stages Subsequent to the procedure described herein to produce polyaluminum chloride of 12.0% of A1203 and 33% of basicity All references cited herein are incorporated by reference in their entirety. Having now described the invention, it will be understood by those skilled in the art that the invention it can be performed within a broad and equivalent range of conditions, parameters and the like, without affecting the spirit or scope of the invention or any modality thereof.

Claims (40)

1. CLAIMS 1. - Process for producing polyaluminium chloride, comprising: a) mixing a first solution comprising sodium aluminate, a second solution comprising basic aluminum chloride to produce a milky suspension, wherein: i) the mixing is carried out performed under sufficiently high shear conditions to avoid gel formation; ii) the temperature of the mixture is maintained below 50 ° C, and b) obtain a clear product solution comprising polyaluminium chloride.
2. 2. The process according to claim 1, wherein the clear product solution of step (b) is obtained by gradually increasing the temperature of the suspension produced in step (a), u a solution of clear product comprising polyaluminium chloride.
3. 3. The process according to claim 1, wherein the clear product solution of step (b) is obtained by allowing the suspension produced in step (a) to clear without applying additional heat.
4. 4. The process according to claim 1, wherein the temperature of the mixture in step (a) is maintained at or below 40 ° C.
5. 5. - The method according to claim 1, wherein the mixing is carried out in the presence of a speed gradient of less than 1000 reciprocal seconds.
6. 6. The process according to claim 1, wherein the second solution comprising basic aluminum chloride is made by reacting a source of aluminum oxide trihydrate with hydrochloric acid or a combination of hydrochloric acid and phosphoric acid.
7. 7. The process according to claim 3, wherein the calcium carbonate is added to the second solution comprising basic aluminum chloride before mixing with the first solution consisting of sodium aluminate.
8. 8. The process according to claim 1, wherein further comprises: c) mixing a third solution comprising sodium aluminate with the polyaluminum chloride of step (b), to produce a second milky suspension, wherein the mixing is carried out under sufficiently high shear conditions to avoid gel formation; and (d) obtaining a second clear product solution from the second milky suspension.
9. 9. - The method according to claim 8, wherein the second clear product solution of step (d) is obtained by gradually increasing the temperature of the second milky suspension produced in step (c), u a solution of Clear product comprising polyaluminium chloride is obtained.
10. 10. The process according to claim 8, wherein the second clear product solution of step (d) is obtained by letting the suspension produced in step (a) be rinsed without applying additional heat.
11. 11. The process according to claim 8, wherein the temperature of the mixture in step (a) is maintained at or below 40 ° C.
12. 12. The method according to claim 8, wherein mixing in step (a) and mixing in step (c) are carried out in the presence of a velocity gradient of at least 1000 reciprocal seconds.
13. 13. The product prepared by the process of claim 1.
14. 14. Process for producing polyaluminium chlorosulfate, comprising: a) mixing a first solution comprising sodium aluminates, a second solution comprising basic aluminum chlorosulfate, in where: i) the mixing is carried out under sufficiently high shear conditions to avoid gel formation; ii) the temperature of the mixture is maintained below 50 ° C, and b) obtain a clear product solution comprising the polyaluminium chlorosulfate.
15. 15. - The method according to claim 14, wherein the clear product solution of step (b) is obtained by gradually increasing the temperature of the suspension produced in step (a) u a product solution is obtained Of course it includes polyaluminium chlorosulfate.
16. 16. - The method according to claim 14, wherein the clear product solution of step (b) is obtained by allowing the suspension produced in step (a) to be rinsed without applying additional heat.
17. 17. The method according to claim 14, wherein the temperature of the mixture in step (a) is maintained at or below 40 ° C.
18. 18. The method according to claim 14, wherein the mixing is carried out in the presence of a velocity gradient of at least 1000 reciprocal seconds.
19. 19. The process according to claim 14, wherein the second solution comprising basic aluminum chlorosulfate is made by reacting a source of aluminum oxide trihydrate with hydrochloric acid and sulfuric acid.
20. 20. The process according to claim 14, wherein the calcium carbonate is added to the second solution comprising basic aluminum chlorosulfate before mixing with the first solution comprising sodium aluminate.
21. 21. The process according to claim 14, wherein further comprises: c) mixing a third solution comprising sodium aluminate with the polyaluminium chlorosulfate of stage (b), to produce a second milky suspension wherein mixing it is carried out under sufficiently high shear conditions to avoid gel formation; and (d) obtaining a second clear product solution of the second milky suspension.
22. 22. The process according to claim 21, wherein the second clear product solution of step (d) is obtained by gradually increasing the temperature of the second milky suspension produced in step (c), until a solution of clear product comprising polyaluminum chlorosulfate is obtained.
23. 23. The method according to claim 21, wherein the second clear product solution of step (d) is obtained by allowing the suspension produced in step (a) to be rinsed without applying additional heat.
24. 24. - The method according to claim 21, wherein the temperature of the mixture in step (a) is maintained at or below 40 ° C.
25. 25. - The method according to claim 21, wherein mixing in step (a) and mixing in step (c), are carried out in the presence of a velocity gradient of at least 1000 reciprocal seconds. .
26. 26. The product prepared by the process of claim 14.
27. 27.- A process for increasing the basicity of a polyaluminum chloride or polyaluminium chlorosulfate, comprising: a) mixing a first solution comprising sodium aluminate with a second a solution comprising the polyaluminum chloride or the polyaluminium chlorosulfate to produce a milky suspension, wherein the mixing is carried out under sufficiently high shear conditions to avoid gel formation; b) obtaining a clear product solution comprising the polyaluminum chloride or polyaluminum chlorosulfate of increased basicity.
28. 28. The process according to claim 27, wherein the clear product solution of step (b) is obtained by gradually increasing the temperature of the suspension produced in step (a), until a solution of clear product comprising polyaluminum chloride or polyaluminum chlorosulfate with increased basicity.
29. 29. The method according to claim 27, wherein the clear product solution of step (b) is obtained by allowing the suspension produced in step (a) to be rinsed without applying additional heat.
30. 30. A composition comprising polyaluminium chlorosulfate, wherein the polyaluminium chlorosulfate has a basicity greater than 75.3%.
31. 31. The composition according to claim 30, wherein the polyaluminium chlorosulfate has a basicity of about 80% or greater.
32. 32. A composition comprising polyaluminium chlorosulfate, wherein the polyaluminium chlorosulfate has a basicity of approximately 70% higher and wherein the composition does not contain calcium carbonate.
33. 33. - The composition according to claim 32, wherein the composition does not contain an alkaline earth.
34. 34.- A composition comprising polyaluminium chloride, wherein the polyaluminium chloride is approximately 80% basic or greater and wherein the composition is: a) it is at an approximate concentration of 8% of A1203 or greater; and b) contains Al13 detectable by NMR.
35. 35.- A composition comprising polyaluminium chlorosulfate, wherein the polyaluminium chlorosulfate is approximately 80% basic or greater and wherein the composition is: a) it is at an approximate concentration of 8% of A1203 or greater; and b) contains Al13 detectable by NMR.
36. 36.- Process for producing a coagulant composition useful for removing water impurities, comprising: mixing a polyaluminum chloride or a polyaluminium chlorosulfate with an organic or inorganic salt, to produce the coagulant composition and wherein the polyaluminium chloride or chlorosulfate of polyaluminium is mixed in an amount such that its concentration in the coagulant composition is less than about 25% by weight or more than about 75% by weight.
37. 37.- The method according to claim 36, wherein the organic or inorganic salt is selected from the group consisting of: ferric chloride, ferric sulfate, ferrous sulfate, aluminum sulfate, aluminum chloride and quaternary ammonium chlorides.
38. 38.- A composition useful as a coagulant in water purification processes, comprising: a) an organic or inorganic salt; and b) a polyaluminium chloride or polyaluminium chlorosulfate present in the composition at a concentration of either about 25% by weight or less or about 75% by weight or more.
39. 39.- A composition according to claim 36, wherein the organic or inorganic salt is selected from the group consisting of: ferric chloride, ferric sulfate, ferrous sulfate, aluminum sulfate, aluminum chloride and quaternary ammonium chlorides.
40. 40.- A process for removing impurities from water, comprising: a) mixing the composition of claim 37 or 38 with water containing impurities; b) allowing the mixture formed in step (a) to flocculate; and c) removing the flocculant formed in step (b) to produce water, wherein the concentration of the impurities has been reduced.