Process for the separation of foam from effluents of coke oven plants

In a process for the separation of the mixture of tar and ammonia liquor produced in the manufacture of coke from finely divided coal, wherein a mixture consisting of tar, ammonia liquor and condensate is freed from coarse particles in a primary decanter with concomitant development of a surface suspension and foam of "swimming tar", the improvement wherein the suspension and foam floating on the surface of the ammonia liquor in the primary decanter is removed by traveling mechanical skimmers, delivered to a foam separator, and permitted to reside in the foam separator for at least two hours to effect separation of a water phase, removing the water phase from the foam separator, and recycling it to the primary decanter.