高硫高碳铝土矿拜耳法生产中石灰对碳硫平衡的影响

Effect of Lime on Carbon-sulfur Balance in Production of High-sulfur and High-carbon Bauxite by Bayer Process

高硫高碳铝土矿在高温拜耳法溶出生产中碳、硫的进出平衡控制至关重要,关系到溶液体系中碳碱和硫含量对生产的影响是否可控。在配料中石灰是最重要及使用量最大的添加剂,在常规配灰范围内,石灰中含碳量占进入流程总无机碳的30%~40%,经研究石灰配入量和自身含碳量对系统碳、硫进出平衡有明显的影响。生产中,在赤泥C/S比为0.45~1.0时,总体上碳、硫进入赤泥的排出量随配灰的降低而增加,其中C/S容易实现进出平衡,有机碳又比无机碳容易实现进出平衡。在使用高硫高碳铝土矿拜耳法生产中要加大碳的排除,建议根据溶出指标情况尽量降低配灰,通过提高石灰质量或分解母液化灰提前排除石灰中的碳,同时控制矿石硫的含量。

It is very important to control carbon and sulfur balance in the high-temperature Bayer leaching production of high-sulfur and high-carbon bauxite,which is related to whether the influence of carbon alkali and sulfur content in the solution system on production is controllable.Lime is the most important and widely used additive in the blending process.Within the conventional blending range,the carbon content in lime accounts for 30%-40% of the total inorganic carbon entering the process.The amount of lime added and its own carbon content have significant impact on the balance of carbon and sulfur in and out of the system.In the production process,when the C/S ratio of red mud is from 0.45 to 1.0,the overall emission of carbon and sulfur entering the red mud increases with the decrease of blending,in which C/S is easy to achieve balance,and organic carbon is easier to achieve balance than inorganic carbon.In the production of bauxite with high sulfur and high carbon in Bayer process,it is necessary to increase the removal of carbon.It is suggested to reduce the amount of lime as far as possible according to the digestion index,remove carbon in lime by improving the quality of lime or dissolving the lime using spent liquor after precipitation,and control the sulfur content of the ore.