Aluminium sulfate
Aluminium sulfate, alternatively spelled either aluminum or sulphate.
Other names: Cake alum, Filter alum, Papermaker's alum, Alunogenite.

Empirical formula (anhydrous) : Al2(SO4)3
Molar masses :
Al2(SO4)3 = 342.15 g·mol-1(anhydrous)
(O = 56,11 %, S = 28,12 %, Al = 15,77 %)
Al2(SO4)3, 18 H2O = 666.42 g·mol-1 (octadecahydrate)
Al2(SO4)3, 14 H2O = 594 g·mol-1

Aluminium sulfate is sometimes referred to as a type of alum. Alums are double sulfate salts, with the formula AM(SO4)2·12H2O, where A is a monovalent cation such as potassium or ammonium and M is a trivalent metal ion such as aluminium. The anhydrous form occurs naturally as a rare mineral millosevichite, found e.g. in volcanic environments and on burning coal-mining waste dumps. Aluminium sulfate is rarely, if ever, encountered as the anhydrous salt. It forms a number of different hydrates, of which the hexadecahydrate Al2(SO4)3•16H2O and octadecahydrate Al2(SO4)3•18H2O are the most common. The heptadecahydrate, whose formula can be written as [Al(H2O)6] 2(SO4)3•5H2O, occurs naturally as the mineral alunogen.

Aluminium sulfate may be made by adding aluminium hydroxide, Al(OH)3, to sulfuric acid, H2SO4:

2 Al (OH)3 + 3 H2SO4 >>> Al2 (SO4)3, 6 H2O

It is available in various solid forms (depending on the manufacturer):

Main features :

Solid (anhydrous)
Solid "nutty"
% Al2[SO4]3
% Al2O3
17 (minimum)
Volumetric mass density ( 20 °C)
2.672 kg/m3
1690 kg/m³ (±7)
1200 kg/m³ (±10)
Acidity (pKa)

Solubility in water (soft water) in relation of température (g / L) :
(g/L = g as Al2(SO4)3 per liter of solution)

The insoluble portion is maximum 0.3% (w / w).
The solutions are to be stored (preferably) above 0 ° C.

Chemical action.
The chemical action of conventional coagulants gives:

A formulation for water treatment.
Aluminium sulfate react with dissolved calcium bicarbonate.
12 Al2[SO4]3,14H2O...+ ...3 Ca[HCO3]2 .............>>>>>>.... 2 Al[OH]3 ...+ ...6CO2.....+....3CaSO4
........(342+252)=594.................(3x162)=486 or 30°F as TAC v ...........(2x78)=156............(6x44)=264.........(3x96 as SO4)=288

Par mg/L aluminium sulfate added there (30/594) = 0.05 °F lower Alkalinity (TAC), and is formed (264/594) = 0.444 mg of free CO2, and is also formed (156/594) = 0.263 mg of aluminum hydroxide (as insoluble flocs), and (288/594) = 0.485 mg of dissolved sulphate.

Standard products used for the production of drinking water: Official French Bulletin - Aluminium sulfate : NF EN 878.



Alzheimer's disease:
There have been studies that have found an association between exposure to and long-term use of antiperspirants and Alzheimer's disease, however the studies also have shown that the association is negligible (less than 1%). There is no adequate evidence that exposure to aluminium in antiperspirants leads to progressive dementia and Alzheimer's disease.

Breast cancer:
The International Journal of Fertility and Women's Medicine found no evidence that certain chemicals used in underarm cosmetics increase the risk of breast cancer. Ted S. Gansler, MD, MBA, the director of medical content for the American Cancer Society, stated "There is no convincing evidence that antiperspirant or deodorant use increases cancer risk".

The European Journal of Cancer Prevention stated "underarm shaving with antiperspirant/deodorant use may play a role in breast cancer. "The journal Breast Cancer Research proposed a link between breast cancer and the application of cosmetic chemicals in the underarm, including aluminium, with oestrogenic and/or genotoxic properties. Personal care products are potential contributors to the body burden in aluminium and newer evidence has shown that more aluminium is deposited in the outer regions than the inner regions of the breast. But whether differences in the distribution of aluminium are related to higher incidence of tumours in the outer upper region of the breast remains unknown.

Effects on the environment.
Aluminum sulfate may decrease the pH of stream, thus representing a potential threat to aquatic fauna and flora (stream, river, groundwater).

Sources : personal and Wikipedia, the free encyclopedia.

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