High carbon ferrochrome slag is a byproduct of High Carbon Ferrochrome (HCFeCr) production in submerged arc furnaces. The slag is conventionally tapped from the furnaces and granulated before being dumped as waste. The major uses of the slag have been in road and civil engineering construction and in production of refractories. HCFeCr slags however, contain appreciable amounts of residual ferrochrome alloy which can be liberated and recovered profitably using cheap and environmentally friendly gravity concentration methods. In this work the milling behavior of a high-carbon ferrochrome slag is investigated. Milling experiments for a typical HCFeCr slag were conducted using a 0.3 by 0.282 m laboratory ball mill to establish liberation as a function of particle size and to determine the associated key breakage parameters like the breakage function (B-ij) and selection function (S-i). The breakage parameters were obtained using the monosize fraction method by milling the following size fractions -132 + 9.5 mm, -9.5 + 5.6 mm, -5.6 + 4 mm, -4 + 2.8 mm, -2.8 + 1.18 mm and -1.18 + 0.15 mm. The effects of powder filling and mill speed were also tested experimentally. An increase in the milling speed from 75% N-crit to 85% N-crit caused an increase in the selection functions of different fractions however a further increase to 90% N-crit resulted in a drastic reduction in the rate of milling across all size fractions. Increasing the powder filling from 40% to 60% caused a marked increase in the selection functions for the particles in the size fraction -5.6 + 4 mm and smaller and a decrease in the selection functions for the particles in the size fraction -9.5 + 5.6 mm and larger. A further increase in the powder filling to 80% caused a marked fall in the selection functions for all size fractions to values lower than those obtained at 40% powder filling. The results from the size by assay test-work showed that the sizes of particles that contain the highest amount of the ferrochrome alloy and the least amount of silica are in the range -1.18 + 0.6 mm. The milling process has to maximize the generation of particles in this specific size range in order to achieve the best alloy recoveries in the downstream concentration unit. (C) 2016 Elsevier B.V. All rights reserved.