Foam formation of Slag-Quartz-$ extrm{Na}_2 extrm{CO}_3$ system was investigated. The foaming agent used was sulphide and sulphate compounds which are present in the slag. The microstructures and x-ray analysis of foam slag, the effect of composition and particle size of slag on the formation temperature, and foam size and distribution of slag foam were studied. The Increment of $ extrm{Na}_2 extrm{O}$ in the slag batch composition decrease the initial foam formation temperature and enhance the foam growth. The formation of temperature and soaking time had pronounced effect on the foam growth and increasing the glass phase in the slag foam.