Material Balance Calculations for Refractory Grade Alumina Production Unit

Hi Friends,

There is a tremendous market potential for Specialty grades of alumina all over the globe. In earlier posts, we have discussed about specifications, process route and system design for production of Refractory grade calcined alumina. 

In continuation to our earlier post, we are presenting here systematically a sample material balance calculations for a typical  3000 tpa Refractory grade alumina plant in the present post.


Basic Assumptions:
Annual production rate = 3000 tonnes per year.
Annual operating days = 150 days per year.
Daily operating hours = 20 hours per day.
Input feed material = Chemical grade Hydrate.


Material Balance Calculations:
Thus hourly production rate = 3000 / (150*20) = 1 tonne per hour.
Dust loss through stack = 0.50%.
Miscellaneous handling losses = 0.50%.
Hence dry hydrate feed to Kiln = (1.0*156/(0.99*102) = 1.55 tph.
Moisture in feed hydrate to Kiln = 10% (w/w) - assumed.
Thus Feed hydrate to Kiln = 1.55/0.90 = 1.72 tph.
i.e. Output hydrate from Rotary vacuum filter=1.72 tph.
Solids in feed slurry to Filter=45%.
                                                              290
Specific gravity of feed slurry = ------------------ = 1.55
                                                     242-1.22*45
                                                   1.72
Feed slurry flow to Filter = ---------------- = 2.47 m3/hr.
                                              1.55*0.45
Wash water to Filter = 1.0 m3/tonne of Hydrate.
Total wash water = 1.0*1.55 = 1.55 m3/hr.
                                                                                                    290
Specific gravity of Kiln feed Hydrate with 10% moisture = ---------------- = 2.19
                                                                                             242-1.22*90
Thus volumetric flow of Hydrate from Filter = 1.72/(0.90*2.19) = 0.87 m3/hr.
Therefore, total material flow to Filter = 2.47+1.55 = 4.02 m3/hr.
Flow rate of filtrate = 4.02 - 0.87 = 3.15 m3/hr.


The above calculations broadly cover the material balance from hydrate filtration to calcination unit  for production of 3000 tpa Specialty grade of calcined alumina.
Please put your views / suggestions / remarks / comments, if any.


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Thanks and regards.

Kunwar Rajendra