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China's bauxite resources of low grade diaspore. Therefore, China's alumina production, sintering method to account for a considerable proportion. In the process of production of alumina of the soda-lime sintering method, since the content of clinker Zhongyuan calcium silicate β-2CaO · SiO2 (Jane for β-C2S) of more than 30%, when eluted with the sodium aluminate solution to react, resulting Al2O3 and Na2O into the red mud, resulting in the decline of the dissolution rate of alumina, caustic soda. For this problem, the domestic and foreign scholars have conducted a lot of research work, a number of measures to reduce secondary reactions, but the dissolution process of secondary reaction to the loss is still large. The additive is a surface active material, the additives are added in the clinker leaching process, because of its strong surface adsorption, so that the solid phase surface to form a hydrophobic surface, reducing the surface tension of the solution of sodium aluminate, delay or prevent the Chek The dicalcium silicate mud contact with the sodium aluminate solution to reduce the loss of alumina dissolution process. To this end, this paper mainly clinker leaching process in the best conditions of the dissolution process by adding inhibitors, screening the inhibitory effect of inhibitors, and to explore the settling characteristics of the dissolution liquid. The specific study reads as follows: by orthogonal experiments and single factor experiments investigated the dissolution temperature, dissolution time, the ratio of liquid to solid, liquid adjustment Na2CO3 concentration of alumina dissolution rate, the results show that the best dissolution conditions: digestion temperature 80 ° C dissolution time of 30 min, the liquid to solid ratio 5:1, sodium carbonate concentration of 20g / L, clinker alumina dissolution rate of 91.26%. In order to understand the additives inhibit the inhibitory mechanism of secondary reactions, adsorption theory as a guide, the good results of selected laboratory but the dissolution fluid has a color additive that has not been applied to the actual production of humic acid sodium of adsorbent β-C2S humic acid sodium adsorption behavior. The research results show that the β-C2S Langmuir adsorption isotherm model of humic acid sodium adsorption process, at the same time for two adsorption kinetics. Thermodynamic analysis shows that the adsorption process is physical adsorption and chemisorption with the deposit, mainly physical adsorption. Measured after the adsorption mechanism of the surface active agent and the β-C2S selective sodium pyrophosphate of SDBS, sodium oxalate, sodium citrate, EDTA, NTA, and six kinds of inhibitors, and the secondary reactions of the dissolution process of clinker . Clinker leaching process to add 0.5% inhibitor SDBS compared without additives blank dissolution Al2O3 dissolution rate of 1.84%, the best inhibitory effect. IR spectra analysis and the adsorption mechanism analysis results show that, mainly through chemical adsorption effect between sodium aluminate solution additives SDBS with the red mud dicalcium silicate additive SDBS covering the surface of the red mud, thus inhibiting secondary reactions place. Best inhibitory effect inhibitor SDBS, by examining the red mud settling velocity, the supernatant transmittance and underflow compressed liquid to solid ratio of three indicators inhibitors SDBS dissolution mud settling properties. The research results show that the added SDBS dissolution mud settling properties add inhibitor decreased less. SDBS after dissolution mud, add 0.05% flocculant PAAS dissolution mud sedimentation settling velocity for 12.47mm/min 10min, supernatant transmittance was 68.5% and the settlement 30min compressed liquid to solid ratio of 4.33, the settlement performance to meet production requirements.
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