The chemisorption of diethyl dithiophosphate ion on lead sulfide surface is examined by means of thermodynamic calculations, with particular attention to the surface behavior. Balance equations are written in terms of equilibrium constants and solved to determine the surface coverage and the concentrations of various species under different conditions. The calculations cover various ways of regulating the chemisorption, such as the addition of oxygen, sodium sulfide, or sulfuric acid, the evaporation of hydrogen sulfide, and change in the initial concentration of the collector. Special attention is paid to the precipitation of lead sulfate, which limits the stability region of the dithiophosphate surface species. The results are compared with those for ethyl xanthate presented in part I of this study.