Mineral liberation is one of the primary objectives in comminution circuits for the downstream separation of valuable minerals. Breaking minerals through their grain boundaries (grain-boundary breakage) enables mineral liberation in their natural grain size, removing the need for intensive grinding. This study aimed to evaluate if gaseous carbon dioxide, oxygen, or hydrogen can be used as grinding additives to promote the liberation of chromite grains by grain-boundary breakage. For this purpose, chromite ore particles in the −9.53 + 6.35 mm size fraction were pretreated by exposing them to carbon dioxide, oxygen, or hydrogen flow. Then, the untreated and pretreated samples were broken in a drop-weight tester under the same conditions. Finally, the grade-recovery plots of chromite grains in the selected progeny size fractions and the overall progeny distributions were measured and compared. Pretreatment with carbon dioxide flow was found beneficial for grain-boundary breakage. It significantly enhanced the liberation of coarse chromite grains along with the overall progeny fineness. EPMA analysis showed that the adsorption of carbon dioxide seems to reduce aluminum concentration at grain boundaries, which could be the reason for grain-boundary weakening. These results suggest that carbon dioxide can be used as a grinding additive, reducing the carbon footprint of the mining industry.

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二氧化碳、氧气和氢气促进铬铁矿破碎释放的初步评价

矿物释放是用于下游分离有价值矿物的粉碎回路的主要目标之一。打破矿物的晶界（晶界断裂）可以使矿物以天然粒度释放，无需进行密集研磨。本研究旨在评估气态二氧化碳、氧气或氢气是否可用作研磨添加剂，以通过晶界断裂促进铬铁矿晶粒的释放。为此，-9.53 + 6.35 毫米尺寸部分的铬铁矿颗粒通过将它们暴露于二氧化碳、氧气或氢气流中进行预处理。然后，在相同条件下，将未处理和预处理的样品在落锤测试仪中破碎。最后，测量并比较了所选子代尺寸部分中铬铁矿晶粒的品位恢复图和整体子代分布。发现用二氧化碳流进行预处理有利于晶界断裂。它显着提高了粗铬铁矿晶粒的释放以及整体后代细度。EPMA 分析表明，二氧化碳的吸附似乎降低了晶界处的铝浓度，这可能是晶界弱化的原因。这些结果表明，二氧化碳可以用作研磨添加剂，减少采矿业的碳足迹。它显着提高了粗铬铁矿晶粒的释放以及整体后代细度。EPMA 分析表明，二氧化碳的吸附似乎降低了晶界处的铝浓度，这可能是晶界弱化的原因。这些结果表明，二氧化碳可以用作研磨添加剂，减少采矿业的碳足迹。它显着提高了粗铬铁矿晶粒的释放以及整体后代细度。EPMA 分析表明，二氧化碳的吸附似乎降低了晶界处的铝浓度，这可能是晶界弱化的原因。这些结果表明，二氧化碳可以用作研磨添加剂，减少采矿业的碳足迹。