Problem 4: Material balance in roasting of galena concentrate

Lead concentrate is composed of . The moist concentrate contains . They are roasted down to , the roasted ore being composed of , the last two combined asa silicate.

The furnace is fired with coal containing .

The furnace gas analyses (volume %dry) are  Neglect moisture in air, calculate per ton of moist concentrate (a)the weight of roasted ore and (b)the volume of furnace gases, including moisture,(c)weight of coal .

Solution:

Here analysis of lead concentrate is not known. Consider 1000kg moist concentrate
Let x kg S forms  amount of

(110-x)kg S forms  and hence amount of
From the balance we can get.

and moisture =80kg

Weight of roasted ore can be determined from S content of roasted ore and performing  balance
 in concentrate  in roasted ore  as  in roasted ore

Weight of roasted ore= 874 kg (a) Ans.

Sulphur balance gives volume of dry gas. Addition of amount of water will give wet gas.

Amount of wet gas   Ans (b)
Weight of coal as found from kg Ans (c)