ドロマイトよりCaOおよびMgOの分離製造
1968 年 1968 巻 92 号 p. 7-11
詳細
1968 年 1968 巻 92 号 p. 7-11
CaO is extracted as a soluble Ca-sucrates from calcined dolomite by the solution of cane suger. Casucrates solution is decomposed into CaCO3 and sucrose by blowing CO2 etc. and the sucrose is recovered for reuse. Studies were made to increase the content of MgO by extracting the proper amount of CaO from the dolomite which is consisted of low content of MgO, rather than separating MgO and CaO completely from dolomite.
It has been reported that the compounds such as C12H22O11·CaO, C12H22O11·2CaO and C12H22O11·3CaO are known in the system between sucrose and CaO and the solubility of CaO into sucrose solution changes depending on the rate of formation of the above mentioned Ca-sucrates, and the activity of CaO tends on the formation conditions of sucrates. However, the details of these have not been fully investigated.
In this study, the extracted amount of CaO is examined under various conditions by using the mixture of Mg (OH) 2 and Ca (OH) 2 reagent both in 3 : 7 weight ratio first, and for the calcined dolomite next. The solution of soluble calcium sucrate produced by extracting calcium from the mixture and calcined dolomite is dissociated by (NH4) 2CO3 instead of CO2. The content of MgO in the residue and that of Ca CO3 in the precipitate.
If calcination temperature of the used dolomite is too low, undissociated CaCO3 is remained and if it is too high, considerable amount of CaO is mixed into MgO as the calcium silicates of insoluble form. The recovery of sucrose is the most important problem for the production in commercial scale, but it has not been discussed in this experiments.
