| After more than fifty years of exploitation in Jilantai Salt Lake,Inner Mongolia,the salt lake is facing technical problems such as serious shortage of water supply,aging of salt lakes and increasingly scarcity of deposits that can be directly exploited by mechanery.Water-soluble mining of tailings to produce reclaimed salt has become an inevitable choice for lake salt production.Water-soluble mining from the tailings has some key problems including low utilization rate of resources,diversified brine composition,difficult quality control and low salt grade.High efficiency brine production from tailings has become a key technique for sustainable development of lake salt industry in Inner Mongolia.Given the fact mentioned above,for the liquid ore,this paper firstly studied the law of evaporation salts of the intergranular brine and the brine from the ship mining area are different temperature,respectively,by using forced evaporation constant temperature balance method based on the phase diagram of Na+,Mg2+//Cl-,SO42--H2O quaternary water-salt system.The results showed that when the intergranular brine was evaporated at 25?,the density of the brine was reached 1.2519 g/cm3,the precipitation rate of NaCl was 92.61%,and the purity of NaCl in the precipitated solid phase was 97.01%;when the intergranular brine was evaporated at 35?,the density of brine was reached 1.2420 g/cm3,the precipitation rate of NaCl was 91.32%,and the purity of NaCl in the precipitated solid phase was 97.80%.When the brine in the ship mining area was evaporated at 25?,the density of the brine was reached 1.2618 g/cm3,the precipitation rate of NaCl was 71.02%.and the purity of NaCl in the precipitated solid phase was 95.23%:When the brine in the ship mining area was evaporated at 35?,the specific gravity of the brine was reached 1.2682 g/cm3,the precipitation rate of NaCl was 77.64%,and the purity of NaCl in the precipitated solid phase was 96.71%.Secondly,through the study on the law of evaporation salts of brine after freezing nitrate and frozen nitrate in the brine of ship mining area,the crafts of "freezing nitrate-sun-dried salt " for the brine of the ship mining area was determined.The effects of freezing nitrate temperature,water addition rate and frozen nitrate time to the rate of nitrate removal and sulfate removal rate and the effect of temperature on the law of evaporation and salt formation were investigated.The results showed that when the water content of brine in the ship mining area was 8%,the density of the brine was reduced to 1.1978 g/cm3,and the bring after being freezed at-10? for 12 hours,the density of the brine after the frozen nitrate was 1.1866 g/cm3,the SO42-content in the brine was reduced to 9.84 g/L,the precipitation rate of Glauber's salt was 73.16%.After the frozen nitrate,the brine was evaporated at 25?.When the density of the brine was reached 1.2601 g/cm3,the precipitation rate of NaCl was 93.14%.and the purity of NaCl in the precipitated solid phase was 96.23%.Thirdly,for solid ore,the two-layer salt extraction by mixing ammonia-alkali waste liquid with fresh water and the law of salt lake solid tailings by fresh water are discussed,respectively.The effects of mixing ratio of ammonia-alkali waste liquid and fresh water,reaction time and stirring rate on the concentration of liquid halogen SO42-,Ca2+,Mg2+and other chemical indicators were investigated by intermittent experiment.The results showed that preparation of liquid salt by removing SO42-from saturated two-layer brine by adding ammonia-alkali waste liquid.0.1162 L of ammonia-alkali waste liquid was added and the system was stirred at 300 r/min to for 120 min in each liter of saturated two-layer brine,when the density of the brine was reached 1.1888 g/cm3,high quality liquid salt for alkali production can be obtained by separation.Preparation of liquid salt by removing SO42-in the process of dissolving two-layer salt by mixing fresh water with ammonia-alkali waste liquid.610.15 g of two-layer salt was added and the system was stirred at 300 r/min to for 120 min in the mixed ammonia-alkali waste liquid and fresh water was 1:5.55?6.36 for each 1 L liquid salt preparation,the density of the brine was reached 1.1943 g/cm3?1.2001 g/cm3 that the high quality liquid salt can be prepared.Using ammonia-alkali waste liquid to treat two-layer salt can achieve desulfurization,make the purity of liquid salt higher to meet the requirements of alkali production,and play the role of treating ammonia-alkali waste liquid,recover sodium chloride from waste liquid,save part of fresh water resources and make comprehensive utilization of salt lake resources.Through static primary salt dissolution experiments,the effects of temperature,dissolution mode,concentration of solution and the ratio of ammonia-alkali waste liquid to fresh water on the dissolution and mining of salt lake tailings were investigated.The results showed that the dissolution rate of primary salt increases with the increase of temperature,when the temperature reaches 40?,the upper dissolution rate of the primary salt was 22.43 g/(cm2·h)and the side dissolution rate was 19.35 g/(cm2·h).The dissolution rate of primary salt decreases with the increase of the concentration of solution,when the concentration of NaCl was 0 g/L,the dissolution rate of primary salt was the highest,the upper dissolution rate of primary salt was 16.70 g/(cm2·h),and the side dissolution rate was 13.31 g/(cm2·h);when the concentration of NaCl was 300 g/L.the dissolution rate was the lowest,the upper dissolution rate was 1.13 g/(cm2·h),and the side dissolution rate was 0.31 g/(cm2·h).The ammonia-alkali waste liquid mixed with fresh water dissolves primary salt,and the dissolution rate of primary salt increases with the increase of fresh water ratio.The ammonia-alkali waste liquid:fresh water at 1:0 has the lowest dissolution rate,its upper dissolution rate was 2.04 g/(cm2·h),and its side dissolution rate was 0.86 g/(cm2·h),and the ammonia-alkali waste liquid has the highest dissolution rate when the fresh water is 1:4.the upper·dissolution rate was 16.65 g/(cm2·h),and the side dissolution rate was 12.71 g/(cm2,h).Through the research on Jilantai liquid ore and solid ore,this paper can provide theoretical guidance for the comprehensive utilization of Jilantai salt lake resources. |
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