28 
BULLETIN 1179, U. S. DEPARTMENT OF AGRICULTURE. 
the refining of petroleum, and small percentages of starch. Briquets 
of several sizes were produced under pressures varying from one-half 
to 1 ton per square inch, but none of these binders proved very sat- 
isfactory, either because of the difficulty in removing the briquet 
intact from the machine, or because of the readiness with which the 
briquet shattered. Sulphite pitch, however, which is a by-product 
of the paper industry, proved to be a good binder when added to the 
finely ground mixtures in amounts above 5 per cent, though this 
material adds quite appreciably to the cost of the briquets. 
In both Florida and Tennessee, however, many phosphate deposits 
in their natural state contain much soft phosphate and claylike ma- 
terial of considerable plasticity, and it was thought that the binding 
qualities of this run-of-mine phosphate might prove sufficiently effec- 
tive to produce satisfactory briquets without the addition of an arti- 
ficial binder. Since the binding capacity of this run-of-mine material 
depends largely on the amount of finely divided material or clay 
contained therein, the samples obtained from the various phosphate 
deposits in these two States were ground to 15 mesh in a small grist- 
mill and then submitted to the mechanical analysis ordinarily em- 
ployed in the classification of soils. In Table 12 are given the results 
of these analyses along with the analysis of very finely ground washed 
pebble phosphate of the grade used in the production of an average 
acid phosphate. 
Table 12. — Location, description, and mechanical analyses l of phosphates used in 
briquetting experiments. 
Sample 
No. 
Location. 
Thickness of 
Description. 
Sand, 
1.0-0.05 
milli- 
meter. 
Silt, 
0.05- 
0.005 
milli- 
meter. 
Clav, 
0.005- 
0.0000 
milli- 
meter. 
1 Charleston, S. C, Min- 15 feet-h 
ing & Manufacturing 
Co., Fort Meade, Fla. 
2 | Cummer Lumber Co., do 
Newberry, Fla. 
1-F Downing Phosphate : 
Co., Bartow, Fla. 
1-F (2). J Downing Phosphate 20 feet h 
Co., near Mulberry, 
Fla. 
4-F do do 
1-T Consolidated Phosphate 6 feet . 
Co. , Hickman Count v, 
Tenn. 
3-T Deposit near Gallatin, 4 feet . 
Tenn. 
Washed pebble phos- 
phate. 
Mine-run phosphate. 
do 
4-T 
6-T 
7-T. 
8-T. 
9-T.. 
10-T. 
11-T. 
12-T. 
13-T. 
14-T. 
Mine-run pebble phos- 
phate. 
do 
.do 
Kuhm Phosphate Co., 
Mount Pleasant, 
Tenn. 
....do 
....do 
do 
5 feet. 
Brown phosphate con- 
taining lump rock. 
Brown disin tegrated 
phosphate. 
Similar to No. 3-T 
Brown phosphate con- 
taining lump rook. 
7 feet . . 
14 feet. 
.do. 
Charleston (S. C.) Min- 
ing Co., Wales, Tenn. 
15 feet 
10 feet 3 inches. 
5leet 11 inches. 
5 feet 
4 feet 6 inches.. 
10 to 20 feet.... 
Sample from upper end 
of waste pond. 
Sample taken 63 feet 
from 8-T. 
Sample taken 63 feet 
from 9-T. 
Sample taken 63 feet 
from 10-T. 
Sample taken 63 feet 
from 11-T. 
Sample taken 63 feet 
from 12-T. 
Brown disintegrated 
phosphate. 
Perct. 
45.2 
45.0 
56.2 i 
84.3 i 
78.5 
73.3 
54.1 
55.4 
66.2 
59.0 
42.5 
24.2 
30.4 
11.6 
22.5 
7.2 
50.4 
Perct. 
36.0 
21.0 
7.6 
5.8 
7.2 
14.6 
18.3 
17.6 
16.1 
16.8 
39.0 
50.2 
45.8 
56.7 
41.1 
44.0 
20.4 
Perct. 
18.8 
34.0 
36.2 
9.9 
14.3 
12.1 
27.6 
27.0 
17.7 
24.2 
18.5 
25.6 
23.8 
31.7 
34.4 
48.8 
29.2 
1 Mechanical analyses made according to the method employed in this bureau for the classification of 
soils. 
