Study On The Comprehensive Utilization Of The Waste Solution From Demagging Of Phosphate Ore

A large amount of phosphate ore containing high maguesum can be utilized based on a new technoloy of demagging pretreatment of phosphate ore, using dilute acid. As a result of the demagging pretreatment technoloy a large amount of demagging waste liquor is needed to be controlled and comprehensively utilized, which also is the aim of this paper.At first, the equilibrum and kinetics of Mg²⁺ of demagging waste liquor on the resins have been studied. The equilibrum of Mg²⁺ is benefical and can be described with the stoichiometric displacement model of adsorption in liquid - solid system. The ion exchange kinetics of Mg²⁺ are controlled by the ion - diffusion through particles and can be described with the corresponding kinetical equation of moving boundary model . Its apparent activation energy is calculated to be 25. 12KJ/mol, and reaction order of Mg²⁺ is 0.98, and kinetical constant is 9.60 × 10⁷。 The total kinetical equation is :1-3(1-F)^2/3 + 2(1-F) = 9.60×10⁷× r₀^-2 · [Mg²⁺]^0.98 · expCrystallization kinetics of Mg(OH)₂with the MSMPR crystallizer in the ammonia chloride solutin have been investigated, The equations of the growth rate (G),the nucleation rate(B°), the critical nucleation density (n°)and the main giain size(L_D) have been obtained.High pure magnesum oxide has been obtained (MgO:99.37% ,grain size:0.2 ⁰.3μm)。 The purity of magnesum oxide powder is better than analytical grade MgO(GB9857 - 88), and its purity and grain size is as good as HP - 10 of Konoshima company, which can be used in the electrical ceramic.After serial investigations, a princple process flow, in which almost no waste liquor is discharged, has been developed to control and comprehensively utilize thedemagging waste liquor. In this process flow, Mg + of the demagging wate liquor is extracted to prepare high pure magnesum oxide powder used in the electrical ceramic, and the remaining solutin after extracting magnesum containing P2O5 and SO3 recycles to the phosphoric acid system. According to the principle process flow, the total yield of MgO is 87. 7% .