BJR1QUETTING TESTS. 43 
The tests with coal tars and the different grades of pitch made from these tars indicate 
that probably in the pitches the most satisfactory binders for the manufacture of briquettes 
will be found ; and that these can be made at such a price as will bring the cost of the bind- 
ing material used to not more than 50 to 75 cents per ton of briquettes. Briquettes made 
from a majority of the bituminous coals with a good grade of pitch as a binder are suffi- 
ciently strong to bear ordinal handling; they will stand exposure to the weather for a 
number of years without serious deterioration; and they burn well in the fire. The supply 
of pitch is already large and can be easily increased. The price now ranges from $9 to $11 
per ton. The pitches obtained from different plants and those obtained at different times 
from the same plant varied considerabfy, not only in their boiling points but in other 
respects; and in the case of similar pitches the percentage necessary for the proper work- 
ing of different coals seemed to vary according to differences in the quality of the coals. 
It was found to be better to mix with a nonce king coal 10 to 20 per cent of a coking coal, 
rather than to increase the percentage of pitch. 
In the investigation of the asphalts as binding materials, impsonite from Indian Terri- 
tory was found to be rather unsatisfactory, though in a number of tests with noncoking 
coals the result was improved by the addition to such coal of from 5 to 10 per cent of 
impsonite in addition to from 3 to 5 per cent of ordinary pitch or some other binding 
material. From 4 to 8 per cent of gilsonite and other asphalts from Utah gave fairly 
satisfactory results as a binder. This material is said to exist in Utah and elsewhere in 
large quantities, and while the price is at present too high to permit its extensive use as a 
binder, doubtless should the demand for it in this connection increase the deposits would 
be opened up to such an extent that it might be sold at lower prices. 
Experiments were made with several other asphaltic materials, and though the results 
were such as to warrant further investigation they were not altogether satisfactory. As- 
phaltic tar yielded fairly good results as a waterproofing material in briquettes made with 
starch. Asphaltic materials yielded the best results in waterproofing. 
From 4 to 6 per cent of maltha (a liquid asphalt) used as a binder yielded fairly satis- 
factory results with coking coals. With noncoking coals it was found to be insufficient for 
the purpose. 
Crude petroleums have been tested as binding materials, with satisfactory results. The 
asphaltic petroleums were used successfully in waterproofing briquettes made with a 
starch binder, though it is doubtful whether this practice would prove entirely satisfactory 
in operations on a commercial scale. In the tests the success of the waterproofing was 
fairly proportional to the amount of asphaltic material in the petroleum. As a binding 
material the asphaltic petroleum proved even more successful than when used for water- 
proofing purposes, from 6 to 8 per cent being entirely satisfactory. 
The petroleum residuums proved to be successful binding materials somewhat in pro- 
portion as the per cent of asphalt in them increased. That obtained from the Gulf Refin- 
ing Company, of Port Arthur, Tex., was found to melt at a temperature of 100° C, and 
'about 99.38 per cent of it was found to be soluble in carbon disulphide. Another sample 
of asphaltic petroleum from the Gulf Refining Company flowed at a temperature of 95° C. 
and of this it was found that carbon disulphide would dissolve 99.88 per cent. From 4 to 
6 per cent of this material gave excellent results as a binder for briquettes. 
Water-gas tar, which is obtained from illuminating-gas plants, was not tested sufficiently 
to give satisfactory results, but it is believed that this material could be used as a binder 
if properly mixed with other somewhat similar materials. It is necessary, after this 
material is mixed with the coal, that the mixture should be raised to a sufficiently high 
temperature to liquefy and perhaps even to vaporize the tar. 
The water-gas pitch which was furnished by the Barrett Manufacturing Company flowed 
at a temperature of 92° C. It was found that 4§ to 7 per cent of this pitch, which would 
be equivalent to from 6 to 8 per cent of coal-tar pitch, would make satisfactory briquettes. 
The cost of this binder would be from 45 to 65 cents per ton of briquettes. 
