Polyaluminum chlorides

Aluminum chloride hydroxide [1327-41 -9] also called polyaluminum chloride or PAG, is made by partial hydrolysis of aluminum chloride to form a mixture of polymeric species. It is more expensive than alum on a weight basis, but has advantages over alum such as not lowering the pH as much and better cost-effectiveness in some appHcations. Residual aluminum in the water is said to be lower and performance in cold water is better (6,7). It is sold as a solution (see Aluminum compounds, polyaluminum cm ORiDEs). 

These rosin-based sizes, whether paste, Hquid, or emulsions, can be used to size all grades of paper that are produced at acid pH. The latter include bleached or unbleached kraft Hnerboard and bag paper, bleached printing and writing grades, and cylinder board. In addition, polyaluminum compounds have been used in place of alum, most notably, polyaluminum chloride (48), which can reduce barium deposits where these have been a problem. The barium chloride by-product is more water-soluble than barium sulfate. Other polyaluminum compounds such as polyhydroxylated forms of alum and polyaluminum siHcosulfate have been evaluated as alum replacements. 

Aluminum chloride hydroxide [1327-41 -9] [10284-64-7], AlQ(OH)2 [14215-15-7], AlQ2(OH), products, commonly known as polyaluminum chlorides (PAG), are used for a wide variety of industrial appHcations. Other names for PAG are basic aluminum chloride, polybasic aluminum chloride, aluminum hydroxychloride, aluminum oxychloride, and aluminum chlorohydrate. The presence of polymeric, aluminum-containing cations, the distribution of which can differ gready, typifies PAG products. Although the formation of polynuclear aluminum species in solution has been studied for over a century, there is stiU much controversy concerning aluminum polymerization reactions and the resulting product compositions. 

Internal Sizing. The most widely used internal sizes are alkyl ketene dimers (AKD), alkenylsuccinic anhydrides (ASA), and rosin-based sizes that are used with papermaker s alum (aluminum sulfate with 14 waters of hydration), polyaluminum chloride (PAG), or polyaluminum siUcosulfate (PAS) (61). The rosin-based sizes are used under acidic conditions. Since the mid 1980 s there has been a steady conversion from acid to alkaline paper production, resulting in static to declining demand for the rosin-based sizing systems. Rosin is a complex mixture of compounds and consists primarily of monocarboxyhc acids with alkylated hydrophenan threne stmctures (62). A main constituent of wood rosin, gum rosin and taH-oil rosin is abietic acid. 

Polyaluminum Chloride (PAC), Aln(OH)mCl3n m, where m and n are variable. PAC is a primary coagulant and is usually very effective without requiring any change in pH levels. It will not reduce the alkalinity of the water but also does not materially change the pH level of the water, even if overdosed. Typically, it is supplied as a 30 to 50% strength solution and requires perhaps 5 to 50 ppm of product to be applied to the water. 

Polyalkylcnc glycol monobutylether Polyalkylcnc polyamides Polyaluminum chloride Polyamide RO membranes Polyamides as antifoams... 

Aluminum chlorohydroxide aluminum hydroxychlorided aluminum chloride, basic aluminum chloride hydroxide polyaluminum chloride... 

Polymeric forms of the coagulants (e.g., polyaluminum chloride) are rather useful because they require lower alkalinity consumption and the concomitant lower production of sludge. Once the colloids are destabilized, slow stirring can also help them merge and form relatively large aggregates called floes (hence the name flocculation) that are separated from water by settlement and filtration. In some cases, these floes can be attached to purposefully generated gas bubbles and separated by flotation. 

The aluminum chloride catalyst used in the alkylation is finally rejected from the system as an acidic aqueous solution. This by-product AICI3 is usually best used for waste water treatment. Sale or use of this material is often as an alum or copperas substitute in water clarification. It is also used in U.S. municipal sewage treatment plants, where a valuable side effect is phosphate removal. In Japan it is converted to polyaluminum chloride (PAC) and used for water treatment. Other uses for this aqueous aluminum chloride stream exist. 

A by-product aqueous stream is generated in the first washing step that contains dissolved HCl, alkylate and AICI3. The uses for this byproduct depend upon its purity. It has been used directly in industrial waste water treating and it has been shown to effectively remove phosphate from municipal sewage. In Japan it is converted to polyaluminum chloride, a highly desirable coagulant for waste water. 

Malhotra, S., D. N. Kulkami, and S. P. Pande (1997). Effectiveness of polyaluminum chloride (PAC) vis-a-vis alum in the removal of fluorides and heavy metals. J. Environmental... 

Commercially, aluminum chloride is available as the anhydrous AlQ, as the hexahydrate, AICI36 H2O, or as a 28% aqueous solution designated 32°Be. Polyaluminum chloride, or poly(aluminum hydroxy) chloride [1327-41-9] is member of the family of basic aluminum chlorides. These are partially neutralized hydrates having the formula Al2Clg (OH) 6 H2O where x = 1-5. 

Liquid polyaluminum chloride is acidic and corrosive to common metals. Suitable materials for construction of storage and handling facilities include synthetic rubber-lined steel, corrosion resistant fiber glass reinforced plastics (FRP), ceramics, tetrafluoroethjiene polymer (PTFE), poly(vinylidene fluoride) (PVDF), polyethylene, polypropylene, and poly(vin5i chloride) (PVC). Suitable shipping containers include mbber-lined tank tmcks and rail cars for bulk shipment and plastic-lined or all-plastic drums and tote bins for smaller quantities. Except for aluminum chlorohydrates, PAC products are shipped as hazardous substances because of thek acidity. 

Production figures for polyaluminum chlorides are not released by manufacturers. However, total U.S. production of PAC excluding aluminum chlorohydrate was estimated at 30,000 metric tons in 1989 from Nalco Chemical Company (Naperville, Dl.) and General Chemical Corporation (Parsippany, NY) and retail prices for polyaluminum chloride solutions were approximately 0.30— 0.70/kg. Three U.S. manufacturers of aluminum chlorohydrate, Reheis Chemical Company (Berkeley Heights, N.J.), Courtney Industries (Baltimore, Md.) and Westwood Chemical Corporation (Middletown, N.Y.) are estimated to produce 25,000 metric tons per year. There are other manufacturing companies that utilize all of thek aluminum chlorohydrate internally in antiperspkant products no estimate of this capacity can be made. The wholesale price of aluminum chlorohydrate in 1989 was about 1.00/kg. 

Polyaluminum chloride products used in the treatment of potable (drinking) water must be approved by the National Sanitation Foundation (NSF). NSF certification has superseded EPA approval. Aluminum chlorohydrate for topical use as an antiperspkant is regulated by FDA. 

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