Process for removing sulfate ions using barium carbonate

I’ve heard that factories in the north use the barium carbonate process, but I’m not quite sure about the specifics of how it’s carried out. Experts familiar with this technology are welcome to share their knowledge. This post was last edited by yzhms on 2009-3-4 at 17:55.]

I once read an article that discussed this issue; it mainly involved fine powder of barium carbonate being mixed with acidic saline, reacting afterward and then being fed into a saturation tank for salt formation. However, it is often the case that there is an excess of carbonate, which affects subsequent clarification and filtration. Moreover, when calcium levels are high, the effluent can cause pipes to become clogged. So it also needs to be controlled; stability should be achieved through treatment in conjunction with cryogenic denitration.

If brine is used, simply pump the powder along with it into the brine well, which will increase the reaction time

　　The barium carbonate method utilizes the difference in solubility products of barium carbonate and barium sulfate to achieve the separation of sulfate ions. Shenxx Chemical Co., Ltd. has invented a method for removing sulfate ions from brine using barium carbonate; the characteristic of this method is that fresh brine from an ion-exchange membrane caustic soda plant at 65–80°C, or recycled brine from an asbestos-diaphragm caustic soda plant, with a brine concentration of 150–250 g/L, is placed in a mixing tank containing barium carbonate. An appropriate amount of barium carbonate is added, and after stirring, the barium carbonate is thoroughly mixed with the brine to form a barium carbonate suspension； A barium carbonate suspension is added from the top into a reaction tank containing brine with sulfate ions and calcium ions, allowing the sulfate ions in the brine to react with barium carbonate; the reaction time is 20–40 minutes, and a stirring device is installed in the reaction tank ； The brine from the reaction tank is pumped by a brine pump into the central guiding inner tank of the clarification tank; there, the brine undergoes separation. The clear liquid resulting from this reaction overflows from the upper overflow weir of the clarification tank into the brine tank, where it is then fed into a desalination tank using a desalination pump for desalination ； The unreacted barium carbonate present at the bottom of the clarification tank is pumped back into the reaction tank using a sedimentation pump for repeated reaction. The main advantage of this invention is that, due to the repetitive reaction, the reaction rate of barium carbonate is high ； It is cheaper and safer than the barium chloride method for removing sulfate ions ； It can produce a certain amount of sodium carbonate, reducing the consumption of this refining agent and thus saving on the costs associated with its purchase. Furthermore, the use of barium carbonate, which is cheaper than barium chloride, to remove sulfate ions results in lower costs for sulfate ions in the deionized water. 　　Due to its lower cost, the significant difference in the mass fraction of barium between the two options – 70% in the former and 56% in the latter – as well as the production of soda ash as a by-product during the reaction process, which allows for reduced usage of crude brine in the purification process, this method has attracted attention within China’s chlor-alkali industry. However, the disadvantages of this method are also obvious: its solubility is low, and pipe blockages often occur in practical use. This process is not yet mature, and the existing problems need to be further addressed in production. Currently, only one chlor-alkali enterprise in China uses this method to remove sulfate ions. This post was last edited by yzhms on 2009-3-5 11:29]

Which company is using it? So that we can go and learn from it**

Could the original poster provide more detailed explanations and information? Urgent! Contact: xuqiongwu@163.com