石灰添加方式对一水硬铝石型铝土矿浆预热过程结疤的影响

Influence of lime adding method on scaling process in Bayer preheating process of diasporic bauxite slurry

提出了在一水硬铝石型铝土矿浆预热过程中含硅、含钛及含镁矿物的结疤机理 ,在此基础上深入研究了石灰添加方式对结疤过程的影响规律。石灰在矿浆进入预热过程前加入时 ,由于水化石榴石的生成使含硅矿物结疤速度降低 ,同时由于矿浆中存在较多的Mg(OH) 2 ,有利于其在矿浆中Mg(OH) 2 固相的表面析出 ,可在一定程度上减缓Mg(OH) 2 结疤的生成。石灰在矿浆预热过程之后加入 ,不仅不能避免CaTiO3 结疤的生成 ,同时还有钛酸钠结疤出现。同时 ,石灰前加还有利于预脱硅过程中脱硅率及脱钛率的提高。因此 ,石灰前加即石灰和矿石一起入磨或者将石灰乳加入预脱硅系统 。

The scaling mechanism of Si containing, Ti containing and Mg containing minerals in Bayer preheating process of diasporic bauxite slurry was proposed. The effect of lime adding method on the scaling process was deeply studied. If lime was added to slurry before preheated, the scale formations of Si containing minerals and Mg(OH) 2 were decreased and restrained because of the production of hydrogarnet and a large amount of Mg(OH) 2 in solid phase in slurry. If lime was added to preheated slurry, the scale formation of CaTiO 3 can not be avoided and the sodium titanate scale was produced. In addition, adding lime to slurry before preheated was beneficial to increasing the desilication and detitanation efficiency in predesilication process. Therefore, grinding lime with bauxite or adding lime to slurry in predesilication process can slow down the general scaling rate in preheating process of slurry.