Study On Resource Utilization Of Sulfate Ions In High-Saline Wastewater

With the rapid development of the chemical industry and the deteriorating ecological environment,water treatment issues have received worldwide attention.Among them,the problem of high salinity wastewater treatment is particularly important.High salinity wastewater contains high concentrations of inorganic salts.Direct discharge will not only cause serious damage to the environment,but also a huge waste of resources.At present,most of the inorganic salts extracted by the existing extraction process are sodium chloride and sodium sulfate,causing single type and low economic value.Therefore,it is of great significance to develop other inorganic salt extraction processes to diversify product types.As an important industrial inorganic salt,barium sulfate has a wide range of applications in the medical,coating,paper and so on.However,due to its nature,there are problems such as poor dispersion and uneven crystal habit.Different industries have different quality requirements for the quality index of barium sulfate products such as particle size and crystal habit.It is in this context that this paper systematically studies the preparation of barium sulphate products with different morphologies using sulfate ions from high-salt wastewater.Firstly,the preparation process of micron-sized barium sulfate was studied.The effects of seven additives on the morphology and particle size of barium sulfate were investigated.It was found that micron-sized barium sulfate could be successfully prepared by using aminotrimethylenephosphonic acid as additive.The effects of reactant concentration,solution pH,reaction temperature and the amount of aminotrimethylenephosphonic acid on the morphology and particle size of barium sulfate products were investigated when aminotrimethylenephosphonic acid was used as an additive.And the mechanism of crystal habit and particle size change were explained.Secondly,the preparation method of submicron barium sulfate was studied in this paper.It was found that submicron barium sulfate can be successfully prepared by using methyl glycine diacetic acid as an additive.The orthogonal experiment was designed by single factor variable.The effects of reactant concentration,solution pH,reaction temperature and additive amount on the morphology and particle size ofbarium sulfate products were investigated.The changes of product morphology and particle size were investigated.Then,the theoretical analysis and simulation of the habit of barium sulfate products were carried out.The interaction between methyl glycine diacetic acid and barium sulfate was investigated.The binding energy between methyl glycine diacetic acid and crystal face was calculated.The reason for the change of strontium sulfate crystal habit was explained,and the habit prediction was carried out with the modified AE model.Finally,based on the above research,the main components of high-salt wastewater were determined by X-ray fluorescence spectrometer and potentiometric titrator,and the reaction crystallization process of preparing barium sulfate from high-salt wastewater was developed.,successfully prepared barium sulfate which meets the purity requirements of national standard qualified products.At the same time,based on the above research results,aminotrimethylenephosphoric acid and methylglycine diacetic acid were used as additives to explore the effects of reactant concentration,temperature and additive quantity on product quality,and micron-sized barium sulfate and submicron were obtained.The optimum preparation process of each grade of barium sulfate,the purity of the obtained products all meet the requirements of the first grade of industrial salt.