Stable salt-free polyaluminum chlorosulfates

Abstract

A process for producing a polyaluminum chlorosulfate (PACS) includes adding an aluminum hydroxychloride (AHC) solution having about 38-43% basicity with (1) aqueous aluminum sulfate to form a solution and mixing a solid AHC with the solution to form an aqueous milky suspension or (2) a solid AHC and solid aluminum sulfate and adding water to the solid mixture to form an aqueous milky suspension, and maintaining the milky suspension for a period sufficient to allow the milky suspension to form a clear to slightly turbid solution including the PACS, the PACS having a basicity of 55 to 75%, the average molecular weight of the PACS is greater than or equal to 95 and less than or equal to 111, and salts present in the PACS comprise 0-1.0% sodium chloride by weight and 0-1.0% sodium sulfate by weight.

Claims

1. A process for producing a polyaluminum chlorosulfate (PACS), the process comprising: a) providing an aluminum hydroxychloride solution having about 38-43% basicity; b) mixing aqueous aluminum sulfate with the aluminum hydroxychloride solution to form a solution of aluminum sulfate and aluminum hydroxychloride; c) providing solid aluminum hydroxychloride having formula (I):
Al.sub.2(OH).sub.n(Cl).sub.6-n-zH.sub.2O(I) where 4.3n5.1, and 0<z3; d) mixing the solid aluminum hydroxychloride with the solution of aluminum sulfate and aluminum hydroxychloride to form an aqueous milky suspension, wherein, on a dry weight basis, the ratio of the aluminum hydroxychloride to the aluminum sulfate is 0.75-20 parts aluminum hydroxychloride to 1 part aluminum sulfate; and e) maintaining the milky suspension of step d) for a period sufficient to allow the milky suspension to form a clear to slightly turbid solution comprising the PACS having formula (II):
Al(OH).sub.(3-x-2y)(SO.sub.4).sub.y(II) wherein 1.78<x<2.02, 0.03<y<0.45, and 1.8<x+y/2<2.1; Al:SO.sub.4=2 to 34; Al:Cl=0.9 to 3.0; Al:OH=0.5 to 0.6; the basicity is 55 to 75%; the average molecular weight of the PACS is greater than or equal to 95 and less than or equal to 111; and salts present in the PACS comprise 0-1.0% sodium chloride by weight and 0-1.0% sodium sulfate by weight.

2. The process of claim 1, wherein the aluminum hydroxychloride having formula (I) is between 73% to 83% basic.

3. The process of claim 1, wherein the aluminum hydroxychloride having formula (I) has 0 to 1.5 molecules of water of hydration.

4. The process of claim 1, wherein, in the PACS of formula (II): x=1.78 to 1.82; 3-x-2y=0.35 to 1.1; y=0.065 to 0.45; and x+y/2=1.83 to 2.02.

5. The process of claim 1, wherein, in the PACS of formula (II): x=1.95 to 2.02; 3-x-2y=0.6 to 1.0; y=0.03 to 0.20; and x+y/2=1.95 to 2.1.

6. The process of claim 1, wherein the PACS of formula (II) further comprises a sulfate content of 2.0-30% by weight in a dry state.

7. The process of claim 1, wherein the process is carried out at a temperature of 5-50 degrees centigrade.

8. The process of claim 1, wherein the process is carried out at a temperature of 10-40 degrees centigrade.

9. The process of claim 1, wherein the clear to slightly turbid solution formed in step e) is by mixing the milky suspension while gradually increasing its temperature until the clear to slightly turbid solution is obtained.

10. A process for producing a polyaluminum chlorosulfate (PACS), the process comprising: a) providing an aluminum hydroxychloride solution having about 38-43% basicity; b) mixing the aluminum hydroxychloride solution with solid aluminum hydroxychloride to form an aluminum hydroxychloride mixture, the solid aluminum hydroxychloride having formula (I):
Al.sub.2(OH).sub.n(Cl).sub.6-n-zH.sub.2O(I) where 4.3n5.1, and 0<z3; c) mixing solid aluminum sulfate with the aluminum hydroxychloride mixture, in the presence of water, to form an aqueous milky suspension, wherein, on a dry weight basis, the ratio of the aluminum hydroxychloride to the aluminum sulfate is 0.75-20 parts aluminum hydroxychloride to 1 part aluminum sulfate; and d) maintaining the milky suspension of step c) for a period sufficient to allow the milky suspension to form a clear to slightly turbid solution comprising the PACS having formula (II):
Al(OH).sub.(3-x-2y)(SO.sub.4).sub.y(II) wherein 1.78<x<2.02, 0.03<y<0.45, and 1.8<x+y/2<2.1; Al:SO.sub.4=2 to 34; Al:Cl=0.9 to 3.0; Al:OH=0.5 to 0.6; the basicity is 55 to 75%; the average molecular weight of the PACS is greater than or equal to 95 and less than or equal to 111; and salts present in the PACS comprise 0-1.0% sodium chloride by weight and 0-1.0% sodium sulfate by weight.

11. The process of claim 10, further comprising drying the aluminum hydroxychloride mixture before or after mixing with the solid aluminum sulfate.

12. The process of claim 10, wherein the aluminum hydroxychloride having formula (I) is between 73% to 83% basic.

13. The process of claim 10, wherein the aluminum hydroxychloride having formula (I) has 0 to 1.5 molecules of water of hydration.

14. The process of claim 10, wherein, in the PACS of formula (II): x=1.78 to 1.82; 3-x-2y=0.35 to 1.1; y=0.065 to 0.45; and x+y/2=(1.83 to 2.02.

15. The process of claim 10, wherein, in the PACS of formula (II): x=1.95 to 2.02; 3-x-2y=0.6 to 1.0; y=0.03 to 0.20; and x+y/2=1.95 to 2.1.

16. The process of claim 10, wherein the PACS of formula (II) further comprises a sulfate content of 2.0-30% by weight in a dry state.

17. The process of claim 10, wherein the process is carried out at a temperature of 5-50 degrees centigrade.

18. The process of claim 10, wherein the process is carried out at a temperature of 10-40 degrees centigrade.

19. The process of claim 10, wherein the clear to slightly turbid solution formed in step e) is by mixing the milky suspension while gradually increasing its temperature until the clear to slightly turbid solution is obtained.

20. A package comprising two components for water treatment, wherein the components include: a) solid aluminum sulfate; and b) a mixture of an aluminum hydroxychloride solution having about 38-43% basicity and a solid aluminum hydroxychloride having formula (I):
Al.sub.2(OH).sub.n(Cl).sub.6-n-zH.sub.2O(I) where 4.3<n<5.1, and 0<z<3, wherein, on a dry weight basis, the ratio of the aluminum hydroxychloride to the aluminum sulfate is 0.75-20 parts aluminum hydroxychloride to 1 part aluminum sulfate such that, upon the addition of water, a solution may be formed comprising a polyaluminum chlorosulfate (PACS) of formula (II):
Al(OH)(.sub.3-x-2y)(SO.sub.4).sub.y(II) wherein 1.78<x<2.02, 0.03<y<0.45, and 1.8<x+y/2<2.1; Al:SO.sub.4=2 to 34; Al:Cl=0.9 to 3.0; Al:OH=0.5 to 0.6; the basicity is 55 to 75%; the average molecular weight of the PACS is greater than or equal to 95 and less than or equal to 111; and salts present in the PACS comprise 0-1.0% sodium chloride by weight and 0-1.0% sodium sulfate by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Polyaluminum Chlorosulfates

(2) The present invention is directed to highly sulfated, high basicity polyaluminum chlorosulfate (PACS) compositions that have essentially no (less than 0.5%, and preferably less than 0.1% or 0.05%) by-product salts. These compositions are highly effective at removing impurities from water and wastewater. The PACS have the chemical formula:
Al(OH).sub.xCl.sub.(3-x-2y)(SO.sub.4).sub.y, (formula I),
where: 1.78x2.02; 0.03y0.45; and 1.8x+y/22.1. Ratios are preferably: Al:SO.sub.4=2 to 34 Al:Cl=0.9 to 3.0; and Al:OH=0.5 to 0.6 Basicity should be 55 to 70% by weight (defined as x/3n) and the molecular weight is preferably at least 95 and less than or equal to 111. Specific PACSs of the invention include: Al(OH).sub.1.83Cl.sub.0.75(SO.sub.4).sub.0.21; and Al(OH).sub.2.01Cl.sub.0.93(SO.sub.4).sub.0.03.

(3) Processes of Making PACSs

(4) The present invention includes a process for producing polyaluminumchlorosulfate by mixing dry, solid aluminum hydroxychloride into an aqueous solution of aluminum sulfate. The aluminum sulfate can be purchased commercially or made using processes well known in the art. Aluminum sulfate is manufactured by digesting an aluminum source (aluminum oxide trihydrate, bauxite, etc.) in a solution of approximately 50 wt % sulfuric acid. The mixture is reacted until there is a slight excess of aluminum hydroxide in solution.

(5) Solutions of liquid aluminum sulfate appropriate for the making of PACSs may be prepared from a molten aluminum sulfate solution by diluting it to about 8.3% aluminum oxide content. Dry aluminum sulfate appropriate for the making of PACSs may be prepared by cooling molten aluminum sulfate and then grinding to the appropriate grind specification at a concentration of 17% aluminum oxide. This should be diluted with water to a final concentration of a 1 to 70 wt % equivalent of liquid aluminum sulfate in water prior to the addition of the solid aluminum hydroxychloride. The amount of water is dependent on the basicity of the solid aluminum hydroxychloride and the desired concentration of the PACS. If the PACS is going to be used on site it can be made as dilute as practical, but if it is going to be shipped elsewhere the concentration of the solution should be maximized. Solutions of PACS can be made as high as 20% aluminum oxide or higher. According to a first embodiment, the dry aluminum sulfate may be diluted to 70-100% equivalent of liquid aluminum sulfate in water prior to the addition of the solid aluminum hydroxychloride. According to a second embodiment, the dry aluminum sulfate may be diluted to 30 to 70% equivalent of liquid aluminum sulfate in water prior to the addition of the solid aluminum hydroxychloride. According to a third embodiment, the dry aluminum sulfate may be diluted to 4 to 30% equivalent of liquid aluminum sulfate in water prior to the addition of the solid aluminum hydroxychloride.

(6) The solid aluminum hydroxychloride used in the making of PACSs can be produced by thermally decomposing aluminum chloride hexahydrate in a fluid bed dryer until the desired basicity is achieved. This process may be represented chemically as follows:
2AlCl.sub.3-6H.sub.2O.fwdarw.Heat.fwdarw.Al.sub.2(OH).sub.nCl.sub.(6-n)(H.sub.2O)+H.sub.2O+nHCl

(7) The final basicity of the aluminum hydroxychloride should preferably be 62-83% basic, and should have waters of hydration of 0 to 1.5, preferably 0.5 to 1.2, and most preferably 0.8 to 1.2. It should be added to the aluminum sulfate solution while the solution is mixed using any of devices known in the art for this purpose.

(8) Mixing of the solid aluminum hydroxychloride should continue until it has been mostly dissolved and until the final solution has a clear to slightly turbid appearance. When performed at about room temperature, this will typically take from 3 to 8 hours. If desired, the solution may be mildly heated to speed clarification but the temperature should preferably not exceed 50 degrees centigrade. In general, 10-40 degrees centigrade is a good range for carrying out the reaction at atmospheric pressure.

(9) As an alternative, the PACSs of the invention can be made from a dry, solid mixture of aluminum sulfate and aluminum hydroxychloride. The aluminum hydroxychloride should have a basicity of 62-83% and may be present in the mixture, for example, at a ratio of between 40 grams per gram of aluminum sulfate and 2 grams per gram of aluminum sulfate. The mixture should be diluted with water to a final concentration of 20% to 40% PACS and mixed until all of the aluminum sulfate and aluminum hydroxychloride has been dissolved. All of the other parameters and procedures are the same as those described above.

(10) The procedures described above should result in the formation of PACSs with a sulfate content of at least 0.5% by weight (e.g., 6-8%) and a basicity of 55% or greater (e.g., 58-75%). Most typically, the PACS solution will be added to raw water or wastewater to coagulate and remove impurities. Typically, the PACSs are mixed into raw water at dosage of 10 to 100 mg/L. The water is generally rapidly mixed with the PACS and then is slowly mixed for several minutes. Mixing is then stopped and the impurities that have been attracted to the PACS and are allowed to settle to the bottom of the water. The supernate is then filtered and proceeds through the rest of the treatment process. PACS can be used in wastewater treatment to remove phosphorous and/or impurities. When used for this, 50 to 300 mg of PACS is typically used per liter of wastewater.

(11) Advantages

(12) The highly sulfated PACSs of the present invention are highly effective as flocculants in water treatment procedures and should be less prone to increase lead levels in water than PACls or PACS with a lower percentage of sulfates. Typical high basicity PACSs are made by shearing sodium aluminate into a solution of basic aluminum chlorosulfates. Since these products degrade with temperature, the PACSs are partially decomposed by the heat from the shearing and the heat of neutralization between the alkaline aluminate and the acidic basic aluminum chlorosulfates. In contrast, the products of the present invention are manufactured at low temperatures thereby avoiding heat degradation. The PACSs are preferably made from solid components that can be shipped dry and reacted after receipt by a purchaser. This should reduce shipping costs, minimize degradation due to heat and/or storage, and allow end users to maintain larger stocks. The PACS described herein should be stable for long periods, work efficiently in cold or turbid water and be effective in a broad pH range.

(13) The PACS described herein hydrolyze at different rates dependent on the sulfate to aluminum ratios. The higher the sulfate to aluminum ratio the quicker the hydrolysis rate. For very cold raw waters, that is less than 40 F., it may be desirable to formulate the PACS with high sulfate to aluminum ratios to speed up the rate of hydrolysis. This allows flocculation to occur in very cold waters. For waters that are very warm, it may be desirable to formulate a low sulfate to aluminum ratio, so that the hydrolysis will not occur too fast and not give a chance for the impurities in the water to bind to the PACS.

(14) When producing a PACS having a basicity of about 60%, the sulfate to aluminum ratio is dependent on the basicity of the aluminum hydroxychloride (AHC) used to make the PACS. The process of decomposing aluminum chloride hexahydrate to produce AHC is described in more detail in U.S. Pat. No. 9,878,918, which is incorporate by reference herein in its entirety. In producing AHC, aluminum chloride hexahydrate may be decomposed at elevated temperatures by removing chloride from the molecule as hydrochloric acid and water. The following reactions detail the decomposition:

(15) Hexahydrate Crystal (0% basic) Al.sub.2Cl.sub.6*12H.sub.2O

(16) First step decomposition (16% basic) Al.sub.2(OH)Cl.sub.5*9H.sub.2O+HCl+3H.sub.2O

(17) Second step decomposition (33% basic) Al.sub.2(OH).sub.2Cl.sub.4*7H.sub.2O+HCl+2H.sub.2O

(18) Third step decomposition (50% basic) Al.sub.2(OH).sub.3Cl.sub.3*5H.sub.2O+HCl+2H.sub.2O

(19) Fourth step decomposition (66% basic) Al.sub.2(OH).sub.4Cl.sub.2*3H.sub.2O+HCl+2H.sub.2O

(20) Fifth step decomposition (83% basic) Al.sub.2(OH).sub.5Cl*0.5H.sub.2O+HCl+2.5H.sub.2O (chlorohydrate)

(21) Since a specific amount of energy is needed for each decomposition step, basicities in the middle of the decomposition steps may be difficult to obtain. However, an AHC produced with higher basicities, e.g., produced in the range between the fourth and fifth decomposition steps, may be desirable for specific applications. Embodiments of the present invention include an additional premixing process that allows for the production of PACS from a source of higher basicity AHC. In addition, this process allows a lower amount of aluminum sulfate to be utilized, producing a PACS with a lower sulfate to aluminum ratio, which may be desired in certain applications.

(22) The premixing process includes adding a lower basicity aluminum hydroxychloride (AHC) material, either to the aluminum sulfate or to the higher basicity solid aluminum hydroxychloride material, in order to form a stable solution or a dry blended product that can then be used to form the PACS described herein. A lower basicity aluminum hydroxychloride material may include 8 to 18% aluminum oxide and 0 to 50% basicity, e.g., about 38%-43% basic aluminum hydroxychloride solution, and preferably about 40% basic. The lower basicity AHC may contain a stabilizer, such as sodium sulfate, sodium borate, phosphates and/or phosphoric acid. An aluminum hydroxychloride (AHC) in the higher basicity range includes 65% to 84% basicity, preferably about 73% to 83% basicity or 75% to 81% basicity, and may be made by the decomposition of aluminum chloride hexahydrate, as described in U.S. Pat. No. 9,878,918, which are powders of 40% to 60% aluminum oxide content.

(23) For example, an aluminum hydroxychloride solution having about 38-43% basicity, and preferably about 40% basicity, may be added to an aluminum sulfate solution and then the solid aluminum hydroxychloride material with the higher basicity range may be dissolved in the solution of the aluminum sulfate and the aluminum hydroxychloride with a lower basicity to form an aqueous milky suspension. The ratio of the aluminum hydroxychloride to the aluminum sulfate, on a dry weight basis, is 0.75-20 parts aluminum hydroxychloride to 1 part aluminum sulfate. The milky suspension should be maintained for a period sufficient to allow the milky suspension to form a clear to slightly turbid solution, which includes the PACS described herein.

(24) Alternatively, a dry blended product may be formed by mixing an aluminum hydroxychloride solution with a lower basicity range, e.g., having about 38-43% basicity and preferably about 40% basicity, with the solid aluminum hydroxychloride material with the higher basicity range. For example, blending may be accomplished by spraying the higher basicity solid aluminum hydroxychloride material with the lower basicity aluminum hydroxylchloride solution, e.g., in an apparatus such as a drying kiln, and then the sprayed solid aluminum hydroxychloride material may be dried, if needed. The resulting blend may then be dry blended with a solid aluminum sulfate. These blended powders are stable indefinitely and tolerate heat and freezing without degradation. The blended powder of the sprayed solid aluminum hydroxychloride material and solid aluminum sulfate may be dissolved in water to form an aqueous milky suspension. The ratio of the aluminum hydroxychloride to the aluminum sulfate, on a dry weight basis, is 0.75-20 parts aluminum hydroxychloride to 1 part aluminum sulfate. The milky suspension should be maintained for a period sufficient to allow the milky suspension to form a clear to slightly turbid solution, which includes the PACS described herein.

EXAMPLES

Example 1

(25) In a 600 ml beaker, 130 grams of commercially available liquid aluminum sulfate (8.3% Al.sub.2O.sub.3) is diluted with 202 grams of water. The beaker is stirred on a magnetic stirrer to which is added 146 grams of a solid aluminum hydroxychloride (42% Al.sub.2O.sub.3, 71% basic) powder. The solution is allowed to mix for 24 hours after which the milky solution becomes clear. The solution yields a PACS solution of 15% Al.sub.2O.sub.3, 60.5% basic and 6.3% sulfate.

Example 2

(26) In a pint jar, 350 grams of a solid aluminum hydroxychloride (41% Al.sub.2O.sub.3, 70% basic) powder is blended with 50 grams of dry alum (17% Al.sub.2O.sub.3). This produces a dry PACS of 38% Al.sub.2O.sub.3, 66% basic and 6% sulfate. Six months later the contents of the jar are added to a one liter beaker that contains 600 mls of water, while stirring on a magnetic stirrer. The solution is allowed to mix for 24 hours, after which the milky solution becomes clear. The solution yields a PACS solution of 15.2% Al.sub.2O.sub.3, 66.1% basic and 2.4% sulfate.

Example 3

Producing a Less Basic Aluminum Hydroxychloride (AHC) Solution

(27) In a 2 liter beaker, 1600 g of aluminum hydroxyl chloride of 10.5% Al.sub.2O.sub.3 was heated to 160 F. with 1.4 grams of 85% phosphoric acid. 240 grams of 58% Al.sub.2O.sub.3 and 83% basicity was added to this solution. This produced less basic AHC of 16.7% Al.sub.2O.sub.3, 38% basicity.

Example 4

(28) In a 600 milliter beaker, 104 grams of the less basic AHC produced in Example 3 was mixed with 129 grams of ambient temperature water. 30 grams of commercial liquid aluminum sulfate at 8.3% Al.sub.2O.sub.3 was added to this solution. 52 grams of higher basicity AHC powder (79.4% basic and 52.7% Al.sub.2O.sub.3) was then added to the solution and stirred for 6 hours. This produced a slightly hazy solution that after filtration yielded a clear solution of PACS of 15% Al.sub.2O.sub.3, 60% basic and 2.2% sulfate.

Example 5

(29) In a 600 milliter beaker, 56 grams of the less basic AHC produced in Example 3 was mixed with 120 grams of ambient temperature water. 83 grams of commercial liquid aluminum sulfate at 8.3% Al.sub.2O.sub.3 was added to this solution. 60 grams of 79.4% basic and 52.7% Al.sub.2O.sub.3 AHC powder was then added to the solution and stirred for 6 hours. This produced a slightly hazy solution that after filtration yielded a clear solution of PACS of 15% Al.sub.2O.sub.3, 60% basic and 6.0% sulfate.

Example 6

(30) 30 grams of liquid aluminum sulfate was blended with 50.3 grams of water and 34.5 grams of liquid aluminum hydroxychloride (16.09% Al.sub.2O.sub.3 and 40% basicity). 27 grams of powdered aluminum hydroxychloride (52.7% Al.sub.2O.sub.3 and 79.35% basicity) was added to this solution. The solution was stirred until a slightly hazy solution resulted. After filtration, this yielded a PACS solution of 15.7% Al.sub.2O.sub.3, 60.9% basicity, 4.9% sulfate that was stable and clear for over 6 months.

Example 7

(31) 35 grams of liquid aluminum sulfate was blended with 53 grams of water and 25 grams of liquid aluminum hydroxychloride (17.5% Al.sub.2O.sub.3 and 41.7% basicity). 25 grams of powdered aluminum hydroxychloride (54.1% Al.sub.2O.sub.3 and 81.2% basicity) was added to this solution. The solution was stirred until a slightly hazy solution resulted. After filtration, this yielded a PACS solution of 15.1% Al.sub.2O.sub.3, 62.1% basicity, 5.7% sulfate that was stable and clear for over 6 months.

Example 8

(32) 35 grams of liquid aluminum sulfate was blended with 55 grams of water and 35 grams of liquid aluminum hydroxychloride (17.5% Al.sub.2O.sub.3 and 41.7% basicity). 25 grams of powdered aluminum hydroxychloride (54.1% Al.sub.2O.sub.3 and 81.2% basicity) was added to this solution. The solution was stirred until a slightly hazy solution resulted. After filtration, this yielded a PACS solution of 15.0% Al.sub.2O.sub.3, 60.5% basicity, 5.3% sulfate that was stable and clear for over 6 months.

Example 9

(33) 53.4 grams of liquid aluminum sulfate was blended with 54.2 grams of water and 23.6 grams of liquid aluminum hydroxychloride (17.5% Al.sub.2O.sub.3 and 41.7% basicity). 29.5 grams of powdered aluminum hydroxychloride (54.1% Al.sub.2O.sub.3 and 81.2% basicity) was added to this solution. The solution was stirred until a slightly hazy solution resulted. After filtration, this yielded a PACS solution of 15.0% Al.sub.2O.sub.3, 60.5% basicity, 7.5% sulfate that was stable and clear for over 6 months.

Example 10

(34) 32 grams of liquid aluminum sulfate was blended with 59 grams of water and 38 grams of liquid aluminum hydroxychloride (15.7% Al.sub.2O.sub.3 and 42.4% basicity). 31 grams of powdered aluminum hydroxychloride (50.1% Al.sub.2O.sub.3 and 77.2% basicity) was added to this solution. The solution was stirred until a slightly hazy solution resulted. After filtration, this yielded a PACS solution of 15.1% Al.sub.2O.sub.3, 60.5% basicity, 4.5% sulfate that was stable and clear for over 6 months.

Example 11

(35) 31.7 grams of liquid aluminum sulfate was blended with 61 grams of water and 34 grams of liquid aluminum hydroxyl chloride (15.7% Al.sub.2O.sub.3 and 42.4% basicity). 33 grams of powdered aluminum hydroxychloride (49.0% Al.sub.2O.sub.3 and 75.6% basicity) was added to this solution. The solution was stirred until a slightly hazy solution resulted. After filtration, this yielded a PACS solution of 15.1% Al.sub.2O.sub.3, 60.4% basicity, 4.5% sulfate that was stable and clear for over 6 months.

Example 12

(36) Using a spray bottle, 52 grams of 79.4% basic and 52.7% Al.sub.2O.sub.3 AHC powder was sprayed with 104 grams of the less basic AHC produced in Example 3. 30 grams of commercial dry aluminum sulfate at 17.0% Al.sub.2O.sub.3 was added to this solution. The mixture was blended till uniform. This produced a dry composition of PACS of 27.7% Al.sub.2O.sub.3, 60% basic and 4.15% sulfate. This composition was then mixed with water to produce a PACS solution.

Example 13

(37) 70 grams of aluminum hydroxychloride solution (15.7% Al.sub.2O.sub.3, 42.6% basicity) was added to 58 grams of powdered aluminum hydroxychloride (54.1% Al.sub.2O.sub.3, 81.2% basic). The mixture was pasty and clumpy. The mixture was allowed to dry on a heated hotplate at 200 F. for 2 hours. The mixture appeared dried and was broken up with a spatula to produce a mixture of fine powder and coarse granules. This mixture was blended with 43.2 grams of granular aluminum sulfate. This material was allowed to sit for a week after which the mixture was added to 160 grams of water in a stirred beaker. The mixture was allowed to stir overnight and produced a slightly hazy solution that was clear after filtration. This yielded a PACS solution that was 15% Al.sub.2O.sub.3, 60.7% basicity and 6.2% sulfate.

(38) All references cited herein are fully incorporated by reference. Having now fully described the invention, it will be understood by those of skill in the art that the invention may be practiced within a wide and equivalent range of conditions, parameters and the like, without affecting the spirit or scope of the invention or any embodiment thereof.