Settling Rate by Particle Size
To Drive off Moisture (theoretical) per Ton (2,000 lbs.) of Dry Material. Total B.T.U. include 63,840 B.T.U. to raise temperature of material from 60° F. to 212° F. at which point evaporation takes place (at sea level); specific beat of material taken as 0.21.
Coal assumed to have 12,000 B.T.U. per’lb. as used and is for 100% efficiency as specified. Table of coal added to original data by The General Engineering Company.
ROTARY DRYERS have efficiencies of 50% to 70%; coal consumption may be determined from the above table by subtracting pounds of coal corresponding to percent moisture in the dried product from the pounds of coal to percent moisture the feed, and dividing by the efficiency expressed decimally.
Capacity 250 to 660 lbs. water evaporated per sq. ft. of section per 24 hours. Rabble Dryers are frequently used for drying concentrates; generally have a cast iron bottom, heated on the under side; the maternal being dried is moved along, counter to the flow of the heating gases, by rabbles; evaporated moisture usually goes direct into the room.
Capacity: 50 to 75 pounds of water evaporated per 24 hours, per sq. ft. Power: 3 to 10 H.P. hours per ton of water evaporated. Fuel efficiency: About 50%, ….Read more
Example 1) It is desired to give 48 hours of contact on 100 tons per 24 hours of 2.7 specific gravity ore in a pulp of 40% solids (1:1.5). What size agitators will be needed?
Total volume equals 59.85 –> from our Pulp Density tables.
Tons feed equal 100.
59.85 time 100 equals 5,985 cu. ft. (total volume 24 hour agitation).
Therefore, 5,985 times 2 equals 11,970 cu. ft. (Total volume 48 hours agitation).
We find that 15′ x 4.5″ x 16′ and 1″ Bolted Steel Tank has an available capacity of 2,860 cu. ft.; therefore, four of these will handle the job.
Or we find that four 15′ x 16′ Welded Steel Tanks would give this approximate capacity or four 16′ x 16′ Wood Tanks would be suitable for this application.
Example 2) It is desired to condition 420 tons of 2.9 gravity ore for 25 minutes in a pulp of 30% solids (1:2.33) What size conditioner will be required?
Conditioning factor equals 0.0594.
Number of minutes equals 25.
0.0594 times 25 equals 1.485.
Number of tons equals 420.
1.485 times 420 equals 623.7 (0.0594 times 25 times 420 equals 623.7).
This time we find that 9′ and 2 5/8″ X 10′ Bolted Steel Tank gives an available capacity of ….Read more
An example of how you can calculate the slurry flow/volume of a given SG, %Solids and Tonnage.
EXAMPLE: 3,400 tons of dry solids is processed in 24 hours in water with a specific gravity of 1.0 and the
concentration of solids by weight is 33% with the solids having a specific gravity of 3.7 then using the formula below: