Hi Haiyou, could you please help sort this out regarding the issue with sodium hypochlorite?
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There’s another question: does sodium hypochlorite decompose to form sodium hydroxide? Inside the tower, I looked it up online; it’s a reversible reaction. But after checking all the reaction equations, I’m still a bit skeptical? ? Another issue is related to the recycling of clean dust – why does the pH level increase as more of it is recycled? I don’t understand it, but it seems to be the case. I’d like to conduct a theoretical analysis to find out the reason ? ?
Under different conditions (temperature, light, other reactants, and impurities), many reversible reactions can occur; products such as Cl, Cl2, O, OH, etc., may be produced, and it is impossible to generalize based on the conditions alone. After the reaction in the purification tower, both H2S and PH3 exist in acidic form; the pH will not increase. Do you mean an increase in pH after the waste liquid has been neutralized with alkali?
The waste liquid resulting from the reaction in the purification tower is recycled; it is transferred from the purification tower to the recycling tank, with a portion of it being discharged outside
I’m not sure; I’ve forgotten all the high school knowledge.
For our finished product, the effective chlorine content of sodium hypochlorite is around 13.5, while the free alkali content is about 0.5; the pH level is approximately 12–13. We prepare sodium hypochlorite using water and fresh sodium hypochlorite, so that the effective chlorine concentration lies between 0.085 and 0.12, with the pH kept at around 7–8. 1. What does effective chlorine refer to? Whether it’s atoms or highly charged ions, sodium hypochlorite used in industry is acidic in nature and possesses primarily oxidizing properties. 2. Why is it necessary to reduce the effective chlorine content? ? Thank you very much
Below is dongping001’s reply dated 2009-11-10 at 22:29, for your reference: The main component of sodium hypochlorite solution is hypochlorite ion; however, chlorous acid and chloric acid may also be present. Regardless of the type of chlorine, it is always measured by the amount of chlorine that can be released by the solution, which is referred to as effective chlorine and is expressed as a mass fraction of Cl. That is, regardless of which chlorate reacts with iodide, it is reduced to chloride, but the amount of iodine produced varies; 2H+ + ClO- + 2I- = I2 + Cl- + H2O ； 4H+ + ClO2- + 4I- = 2I2 + Cl- + H2O ； Chlorate produces 3 moles of iodine, which is then titrated using a sodium thiosulfate standard solution; if it is chlorite, its effect is equivalent to twice that of chlorate. The calculation formula is X = c*V*0.03545/(m*10.0/500)×100 = 177.25c*V/m (according to the national standard; for ordinary cases: X = c*V*0.03545/m×100). In this formula, c represents the actual concentration of the sodium thiosulfate standard titration solution, in mol/L ； V – Volume of the sodium thiosulfate standard titrant, in mL ； m – the mass of the sample, in g ；
Thank you so much; it’s great to meet you