MANUFACTURE OF PHOSPHORIC ACID. 
29 
Table 12. — Location, description, and mechanical analyses of phosphates used in 
briquctting experiments — Continued. 
Sample 
No. 
Location. 
Thickness of 
stratum. 
1 Sand, 
Description. Mg* 
meter. 
Silt, 
0.05- 
0.005 
milli- 
meter. 
Clay, 
0.005- 
0.0000 
milli- 
meter. 
15-T... International Agri- 
cultural Corporation, 
Wales, Tenn. 
16-T... ---- do 
10 to 20 feet 
do 
Per ct. 
High-grade disintegrated 51.6 
phosphate. 
Low-grade disintegrated 53. 7 
phosphate. 
Mino-run brown phos- ! 46.5 
ptiate. 
do 1 62.4 
Per ct. 
18.4 
13.8 
19.7 
16.6 
Per ct. 
30.0 
32.5 
18-T . . . 
19-T 
Federal Chemical Co., 
Ridley, Tenn. 
fin 
6 to 10 feet 
.... do 
33.8 
21.0 
20-T do ' do 
do 52.6 
22.4 
25.0 
It will be noticed that with few exceptions all of the samples of 
run-of-mine phosphates contained in their natural state much higher 
percentages of very finely divided material or clay than the high- 
grade washed pebble phosphate (Sample No. 1) even though the 
latter w T as ground in a ball mill for a considerable length of time. 
While most of these samples would yield excellent briquets when 7 to 
10 per cent of water was added and the material submitted to a pres- 
sure of from one-half to 1 ton per square inch, the ultimate mechanical 
composition of a charge suitable for furnace treatment depends upon 
the amount of sand or higher grade phosphate which must be added 
to give the proper silica-lime ratio for the evolution of phosphoric 
acid at high temperatures. In Table 13 are given the chemical 
analyses of these samples and the quantities of sand or high-grade 
rock which must be added to give a silica-lime ratio of 59 to 41, 
which was the proportion used in the earlier work conducted on a 
semi commercial scale. 
Table 13. — Partial chemical a 
nalysis and silica-lime relations of natural phosphates. 
Sample No. 
Chemical 
analyses. 
Ratio, 
Si0 2 : 
CaO. 
Quantity of sand 
or high grade 
rock to be added 
to 100 parts of 
material to give 
ratio Si0 2 :CaO 
= 59.0 : 41.0 = 
1.439. 
Si0 2 . 
CaO. 
P2O5. 
Fe 2 3 . 
AI2O3. 
1 Total. 
Sand. 
Rock. 
V 
Per cent 
6.85 
32.79 
26.96 
37.57 
45. 20 
10. 00 
30.23 
38.74 
15.53 
18.69 
49.60 
58.94 
56.32 
66.81 
55. 68 
61.18 
23. 42 
22.26 
57.34 
23.86 
16. 50 
28.90 
Per cent. 
44.78 
26.47 
29. 05 
29.70 
24.29 
42.66 
28.17 
23. 00 
38-32 
33. 09 
18.24 
12.20 
15. 16 
8. 05 
12.58 
6.60 
30. 78 
31.41 
12.00 
30.26 
37.41 
28.64 
Per cent. 
31.03 
21.43 
23. 61 
21. 52 
18.36 
31. 86 
22. 03 
17.88 
27.68 
25. 20 
14.21 
10. 23 
12. 05 
6.92 
10.51 
6- 32 
22.70 
23.85 
11.23 
22.76 
25.84 
20.79 j 
Per cent. 
1.48 
""2. 09' 
"*3."26" 
4.06 
4.45 
3.56 
4.84 
3.76 
4.30 
3.98 
4.46 
4.78 
5.68 
5.22 
4.78 1 
4.90 
4. 55 
3.02 1 
3.82 | 
Per cent 
2.13 
2 11.78 
8.40 
2 3.92 
2 4.91 
3.90 
6.94 
5.00 
4.33 
5.54 
4.73 
5.06 
4.41 
6.82 
7. 85 
9. 57 
7.40 
7.79 
7.23 
8.40 
5.50 
6.63 
'Per cent. 
86. 33 
92.47 
90.11 
92.71 
92.76 
91.68 
91.43 
89.07 
89.42 
87.36 
90. 54 
90.73 
91.92 
93. 06 
91.40 
89.34 
289.52 
90.09 
92.70 
89.83 
88.27 
S8.78 
0.1.53 
1.239 
.928 
1.265 
1.861 
.232 
1.073 
1.686 
.405 
. 565 
2.717 
4.830 
3.716 
8.300 
4. 430 
9. 275 
.762 
.708 
4.775 
.788 
.441 
1.070 
Parts . 
57.36 
Parts. 
2 
5.00 
1-F 
14. 85 
5.20 
1-F (2) 
4-F , 
17.70 
1-1 
51.35 
10.27 

3-T 
4-T 
8.20 
6-T 
39.65 
28. 91 
7^T 
8-T 
33.9 
9-T 
60. 1 
10-T 
50.0 
11-T 
80.0 
12-T 
54. 5 
13-T 
74.8 
14-T 
20.85 
22.94 
15-T 
16-T 
58.0 
18-T 
19.64 
37.33 
12.31 
19-T 
20-T 
1 This phosphate was used in reinforcing the lower grades of mine-run material. 
8 Combined oxides of iron and aluminum. 
