The mixture of chromite ore concentrate from El-Baramiya region and soda ash with and without lime was briquetted and roasted at different temperatures (900-1100 deg C), in a flow of air. The yield of Na_2CrO_4 (chromic oxide recovery in water solution) can be achieved to maximum value when Cr_2O_4: Na_2CO_3 = 1 : 2.5 mole ratio (in absence of CaO), while the maximum recovery of chromic oxide in water can be achieved when Cr_2O_4 : Na_2CO_3 : CaO = 1 : 2.5 : 2.5 mole ratio. The briquetting process affectes on the amount of chromic oxide recovery. Also the controlling mechanism for both processes of roasting (with or without calcium oxide), are controlled firstly (20percent recovery) by chemical reaction, while in the meddle and final stage is controlled by solid diffusion mechanism.
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机译：将来自El-Baramiya地区的铬铁矿精矿和纯碱（含或不含石灰）的混合物压制成块，并在空气流中于不同温度（900-1100℃）下烘烤。当Cr_2O_4：Na_2CO_3 = 1：2.5摩尔比（在没有CaO的情况下）时，Na_2CrO_4的收率（水溶液中铬氧化物的回收率）可以达到最大值，而当Cr_2O_4： Na 2 CO 3 ∶CaO ＝ 1∶2.5∶2.5摩尔比。压块过程影响氧化铬回收量。同样，两种焙烧过程（有或没有氧化钙）的控制机制都首先通过化学反应进行控制（回收率为20％），而在混合过程和最后阶段则通过固体扩散机制进行控制。
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