Basic Research On The Technology Of Efficient Utilization Of Glauberite Ore

The"cavity water-soluble method"is a method widely used in the mining process of glauberite,but this method has the situation that the concentration of sodium sulfate in brine is low,which increases the energy consumption of the subsequent production process.In order to solve this problem,In this paper,using the glauberite ore in Pengshan,Sichuan,after understanding the composition of the glauberite ore,a series of basic researches on the glauberite transformation and concentration,the glauberite system thermodynamic model,and the glauberite decomposition and crystallization mechanism are carried out,mainly in order to obtain high-concentration sulfuric acid.The production conditions of sodium brine are determined,and the production process is determined.The conclusion is as follows:（1）Basic research on glauber’s salt dissolution and crystallization processGlauber’s glauberite structure is a massive compact structure,wherein the sodium sulfate content is 51.18%,and the calcium sulfate content is 33.76%;when the leaching temperature is increased,the sodium sulfate concentration in the glauberite ore powder leaching solution decreases;the mineral powder is dissolved in low-temperature water,It is found that low temperature hydration will destroy the crystal structure of Na₂SO₄·Ca SO₄,so that the sodium sulfate in the crystal exists in the form of sodium sulfate decahydrate;using water with a temperature higher than 30℃to dissolve the crystal ore,it is found that the concentration and dissolution of sodium sulfate in brine The rate is better than the direct leaching effect of raw ore powder.（2）Research on thermodynamic model of Na₂SO₄-Ca SO₄-H₂O systemBased on the e NRTL model,the physical properties and solubility of the glauberite leaching brine Na₂SO₄-Ca SO₄-H₂O system and its sub-systems were calculated,and the liquid phase characteristic parameters of two groups of salt pair-water and salt pair-salt pairs were obtained respectively;Elemental and ternary multi-temperature solubility data were used to obtain six sets of solid-phase thermodynamic parameters of salt Ca SO₄ and its hydrates and double salt,through the prediction of the phase region,it is determined that the temperature range where the decomposition and transformation of glauberite can occur is-1.24°C to 27.38°C,which makes the continuous expression of the thermodynamic properties of the glauberite brine system more perfect,and is also useful for guiding process production.has a very important meaning.（3）Research on the decomposition and crystallization Mechanism of glauber’s salt and the thermal effect of the processThe dynamic process model of glauberite hydrolysis was established,including solid-liquid material balance,solid-liquid equilibrium equation,enthalpy balance equation and kinetic model with glauberite decomposition as the key reaction.The kinetic model expresses the driving force of glauberite decomposition as the difference between the liquid-phase activity product and the zero-variable point activity product,and considers the effects of glauberite and water.By fitting the temperature change in the adiabatic process,the activation energy,reaction rate constant,and reaction order of the reaction are obtained as 2.4 KJ/mol,2.5×103 s^-1,6.42,respectively.These parameters are well used for isothermal processes.The trend of thermal effect is expressed,and the heat transfer coefficient of the heat dissipation process is determined.Based on this,the changes of state parameters such as material temperature,glauberite conversion rate,sodium sulfate decahydrate production,and system solid-liquid ratio changes with ambient temperature and time were predicted in the conversion process,which provided an effective method for the determination of process conditions Support.（4）Research on concentration technology of glauber’s saltUnder the low temperature environment,the mineral powder is crystallized by adding water,and the brine containing more than 320 g/L of sodium sulfate can be obtained by dissolving with low-concentration ore brine at about 28℃.The conclusion can provide the basis for the control of the process conditions of mirabilite transfer crystallization and concentration,and determine the process plan.