Method for decomposing sodium hypochlorite

Abstract

The invention discloses a method for decomposing sodium hypochlorite. The method comprises the following steps: carrying out gas and liquid mixing and absorbing reaction on exhaust gas which contains chlorine and mercuric chloride vapor and comes from a mercuric chloride synthesis working procedure by using a sodium hydroxide solution with the weight concentration of 5-10%, so as to produce a sodium hypochlorite solution, cooling and dissolving the mercuric chloride vapor into the sodium hypochlorite solution, enabling air to escape from the surface of the solution, when the pH value of the solution is 10.5-11, adding nickel chloride (or nickel oxide or nickel hydroxide) according to the ratio that 25kg of nickel chloride (or nickel oxide or nickel hydroxide) is added into every 1-1.5t of sodium hypochlorite solution, stirring and mixing uniformly, and completing decomposition when the pH value is 7-8; separating nickel oxyhydroxide from the solution, thereby obtaining a sodium chloride solution. The method has the advantages that the decomposition of the sodium hypochlorite solution can be accelerated, the recycling of materials can be realized, and the method is safe and environment-friendly.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for decomposing sodium hypochlorite. [0002] Background technique [0003] At present, the fire-method mercuric chloride synthesis process is to pass chlorine gas into a quartz glass retort filled with high-temperature mercury liquid, and the chlorine gas and mercury vapor undergo a combustion reaction to generate mercuric chloride vapor, and the generated mercuric chloride vapor is inhaled by negative pressure for cooling. Inside the tower, rise and cool along the tower; when the temperature drops below the boiling point of mercuric chloride (302°C), mercury chloride vapor begins to crystallize and fall to the bottom of the tower; regularly take out the mercuric chloride at the bottom of the tower, pack it The finished mercuric chloride crystals are obtained. The chlorine-containing tail gas enters the absorption reactor; usually, in order to prevent mercur...

AI Technical Summary

Problems solved by technology

The main problems of this sodium hypochlorite solution are as follows: (1) Poor stability and easy decomposition: sodium hypochlorite solution is very easy to decompose when exposed to light and heat: the decomposition speed is obviously accelerated when the temperature is higher than 30 ° C. If it is exposed to sunlight for about 20 hours, then 90 % of available chlorine is decomposed; even sodium hypochlorite at room temperature is unstable, has strong oxidation and volatility, and brings many difficulties to transportation, storage, use, etc.; (2) low content of available chlorine: due to the use of residual The sodium hypochlorite solution produced by chlorine and dilute sodium hydroxide solution has an effective chlorine content of only 2-3%, which is less than the 5-13% required by the national standard, which is difficult for users to accept; (3) containing highly toxic mercury chloride: When the lye is absorbed, the mercuric chloride (vapor partial pressure) in the tail gas is dissolved in the solution, so that the solution contains more than 0.012% mercuric chloride, and it is easy to cause mercury pollution to spread during use.

The above-mentioned reasons make this sodium hypochlorite solution unable to be used in conventional sodium hypochlorite fields such as bleaching, sterilization, and disinfection, resulting in a backlog of sodium hypochlorite solution, which seriously restricts the production of mercuric chloride.