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Abstract- Solid Waste Sludge (SWS) PDAM are formed by deposition of solid particles in water that has
been given a coagulant such as alumminum sulfate (alum) and PAC (poly aluminum chloride). SWS PDAM
have the content of alumina (Al2O3) quite high, making it possible to get alumina by recovery process.
This research aims to study the recovery process of alumina from SWS PDAM and to determine the
optimum process of alumina recovery.
The recovery process of alumina has divided into three main processes. First process was calcination
material to break the complex bonds aluminosilicate contained in the material, in which some
compound was added before calcination and used to bind the alum compound. The second process is
the solid-liquid extraction (leaching) that serves to separate the silica and alumina. Silica will precipitate
and alumina will dissolve. Next process is the decomposition of hydrolysis, the Al compound will be
heated by adding water so that the hydrated form of alumina.
This research was conducted with several stages. First SWS PDAM is mixed with CaCl2, variation ratio of
CaCl2:SWS PDAM is 0,5:1, 1:1 and 1.5:1, calcined at 800 oC, particle size of 200 mesh, and leached by
HCl using concentration of 4, 6 and 8 M. The solution was added into 100 ml of water and heated. Results
were analyzed as %w/w alumina contained in the solution. The results of the best variations made to
the recovery of alumina in this study is to use a variation of weight ratio 1:1 CaCl2 and SWS PDAM with
HCl concentration on the leaching process of 8M obtained alumina recovery percentage 15.68%.
Keywords: alumina, SWS PDAM, calcination, leaching. |
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