THE MANUFACTURE OF ACID PHOSPHATE. 
15 
(4) Conversion of aluminum phosphate to aluminum sulphate and 
phosphoric acid : 
2 molecules 3 molecules 1 molecule 2 molecules 
2A1P0 4 + 3H 2 S0 4 = A1 2 (S0 4 ) 3 + 2H 3 P0 2 
Wt. 245 Wt. 294 Wt. 343 Wt. 196 
(5) Conversion of calcium carbonate to calcium sulphate, carbon 
dioxide, and water: 
1 molecule 1 molecule 1 molecule 
CaC0 3 + H 2 S0 4 = CaS0 4 
Wt. 100 Wt. 98 Wt. 136 
1 molecule 1 molecule 
f C0 2 + H 2 
Wt. 44 Wt. 18 
If 19G parts b} r weight of sulphuric acid are required to convert 
310 parts of tricalcium phosphate into monocalcium or soluble phos- 
phate, then 0.632 part of acid will be required for every 1 part of tri- 
calcium phosphate. If we use ordinary " chamber acid" of 50° B. 
strength which contains, according to the table on page 5, 62.18 
per cent of sulphuric acid, 1.016 parts will be necessary for every 1 
part of tricalcium phosphate. 
In Table III, modified from one prepared by Wyatt, 1 is given the 
quantity of sulphuric acid of various strengths necessary to bring 
about the reactions outlined above. 
Table III.- — Weight of " chamber acid'''' of various strengths required to convert one 
pound of each of the ingredients of phosphate rock into soluble compounds. 
Material acidulated — Ingredient. 
Tricalcium phosphate (Ca 3 (P0 4 )2) 
Calcium fluoride (CaF 2 ) 
Iron phosphate (FePOO 
Aluminum phosphate ( A1P0 4 ) 
Calcium carbonate ((CaC0 3 ) 
Quantity and strength of acid required. 
B. 49° B. 50° B. 51° B. 52° B. 53° B. 54° B. 55° B 
Lbs. 
1.060 
2.117 
1.640 
2.023 
1.652 
Lbs. 
1.040 
2.067 
1.601 
1.975 
1.613 
Lbs. 
1.016 
2.019 
1.564 
1.929 
1.576 
Lbs. 
0.992 
1.972 
1.528 
1.885 
1.539 
Lbs. 
0.970 
1.928 
1.494 
1.842 
1.504 
Lbs. 
0.948 
1.885 
1.460 
1.801 
1.471 
Lbs. 
0.927 
1.843 
1.428 
1.761 
1.438 
Lbs. 
0.907 
1.803 
1.397 
1.723 
1.407 
Table IV gives the quantities of sulphuric acid of various strengths 
required for every 100 pounds of the phosphate rock. 
Table IV. — Quantities of "chamber acid" required (theoretically) to convert 100 pounds 
of Florida hard rock phosphate into acid phosphate. 
Components of rock. 
Per cent. 
Strength and quantities of acid required 
for 100 pounds of rock. 
48° B. 
50° B. 
52° B. 
54° B. 
Tricalcium phosphate (Ca 3 (P0 4 )2) 
80.0 
4.5 
Pounds. 
84.8 
9.5 
Pounds. 
81.3 
9.1 
Pounds. 
77.6 
8.7 
Pounds. 
74.1 
Calcium fluoride, (CaF 2 ) 
8.3 
Iron phosuhate, (FePO<) 
6.0 
3.5 
5.5 
.5 
12.1 
5.8 
11.6 
5.5 
11.1 
5.3 
10.6 
Calcium carbonate, (CaC0 3 ) 
Silica, (Si0 2 ) 
Moisture, (HoO). 
5.0 
Total 
112.2 
107.5 
102.7 
98.0 
Phosphates of America. 
