urbaf2

The water-washed TNT contains 0.3-0.5% of acid. This value falls to 0.005%

after repeated washing with boiling water.

Pure TNT may be granulated. For this a stream of molten TNT is introduced

into a vat, at a place where two jets of cold water impinge on each other (Fig. 84).

In this way a product melting at 79.5-80.2°C can be obtained.

Water TNT Water

FIG. 84. Granulation of TNT.

The purity of the TNT obtained depends to a great extent on the size of the
crystals formed. The best results are achieved when the crystals are of equal size
and l-2 mm in diameter.
If grade I crystalline TNT is required the acid free TNT is sulphitated. In this
way the melting point may be raised to 80.5°C.

MATERIAL BALANCE

Belenkii [8] reported data on the weight of acids used for 1000 kg of crude TNT
(Table 85).

Process

TABLE 8.5

QUANTITY OF ACIDS USED FOR 1000 KG OF CRUDE TNT

Mixed acid (87.3% of HNO 3

and 8.4% of H 2 SO 4 ) Oleum 93% sulphuric Spent acid

H 2 SO 4

(104% H 2 SO 4 ) acid (as H 2 SO 4 ) from trinitration

HNO 3 kg

kg kg

kg kg

Mononitration 34.4 342.0 -~

35.0

664.5

Dinitration 349.0 197.6 841.0

Trinitration 52.2 518.3 1990.0 178.0

Total 121.6 1209.3 2187.6 178.0 1505.5