A method for manufacturing sulfuric acid and caustic soda by electrolysis of chrome mirabilite in a three-compartment electrolysis

Abstract

The application discloses a method for manufacturing sulfuric acid and caustic soda by electrolysis of three-chamber electrolysis of chrome-containing glauber salt, comprising the following steps: preparing a certain concentration of electrolyte of chrome-containing glauber salt, sulfuric acid anode liquid and sodium hydroxide cathode liquid; adding the electrolyte of chrome-containing glauber salt into the middle cavity of the electrolytic cell of the three-chamber electrolysis device, adding the sulfuric acid anode liquid into the anode cavity of the electrolytic cell, and adding the sodium hydroxide cathode liquid into the cathode cavity of the electrolytic cell; heating the three kinds of solutions, starting the circulating pump, adjusting the current, and performing electrolysis treatment; adjusting the pH value of the electrolyte of chrome-containing glauber salt, and controlling the concentration of the sulfuric acid anode liquid and the sodium hydroxide cathode liquid during the electrolysis process; stopping the electrolysis when the chromium in the electrolyte of chrome-containing glauber salt reaches a certain concentration, pumping out the electrolyte of chrome-containing glauber salt, and returning the electrolyte to the chrome salt leaching section to recover resources such as chromium, aluminum and vanadium. The application comprehensively utilizes sodium sulfate and chromium resources, and industrial raw materials of sodium hydroxide and sulfuric acid are prepared through electrolysis treatment; the chrome-containing glauber salt is harmlessly disposed, the process is safe and environmentally friendly, and the production cost of enterprises is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of resource utilization of industrial solid waste, and particularly relates to a method for manufacturing sulfuric acid and caustic soda by electrolysis of chromium-containing glauber's salt in a three-chamber electrolysis device. BACKGROUND

[0002] In the production process of sodium dichromate, the sodium chromate alkaline leaching solution is acidified with sulfuric acid to generate sodium dichromate and sodium sulfate. The sodium dichromate and sodium sulfate are separated by evaporation and concentration to make the sodium sulfate crystallize and precipitate due to the difference in solubility. However, the precipitated sodium sulfate contains a small amount of sodium dichromate. Since the chromium-containing sodium sulfate contains hexavalent chromium, direct discharge will cause resource waste and environmental pollution.

[0003] At present, the process for disposing the chromium-containing glauber's salt in China is the high-temperature sulfidation alkali process. The glauber's salt is mixed with carbon powder to prepare sulfidation alkali under high-temperature conditions, and the chromium is removed in the form of chromium hydroxide solid. However, this method has large environmental pollution and high energy consumption, and belongs to a state-limited treatment process. At present, the sodium sulfate and chromium resources are comprehensively utilized to produce industrial raw materials sodium hydroxide and sulfuric acid. The chromium-containing alkaline sodium sulfate intermediate liquid can be returned to the leaching section to recover aluminum, vanadium and other elements. The glauber's salt is harmlessly disposed, the process is safe and environmentally friendly, and the economically valuable sodium hydroxide and sulfuric acid are produced, thereby reducing the production cost of enterprises. SUMMARY

[0004] An object of the present application is to solve at least the above problems and / or defects, and to provide at least the advantages to be described later.

[0005] In order to achieve these objects and other advantages according to the present application, a method for manufacturing sulfuric acid and caustic soda by electrolysis of chromium-containing glauber's salt in a three-chamber electrolysis device is provided, which comprises the following steps:

[0006] Step one, preparing a certain concentration of chromium-containing glauber's salt electrolyte, sulfuric acid anode liquid and sodium hydroxide cathode liquid;

[0007] Step two, adding the chromium-containing glauber's salt electrolyte into the middle chamber of the electrolytic cell of the three-chamber electrolysis device, adding the sulfuric acid anode liquid into the anode chamber of the electrolytic cell, and adding the sodium hydroxide cathode liquid into the cathode chamber of the electrolytic cell. The three solutions are heated, the circulating pump is started, the current is adjusted, and electrolysis treatment is performed.

[0008] Step three, adjusting the pH value of the chromium-containing glauber's salt electrolyte and controlling the concentration of the sulfuric acid anode liquid and the sodium hydroxide cathode liquid during the electrolysis process. When the chromium in the chromium-containing glauber's salt electrolyte reaches a certain concentration, the electrolysis is stopped, the chromium-containing glauber's salt electrolyte is pumped out, and the chromium, aluminum, vanadium and other resources are recovered in the chromium salt leaching section. The newly prepared chromium-containing glauber's salt electrolyte is pumped in, and the electrolysis is continued.

[0009] Preferably, in the step one, the mass fraction of sodium sulfate in the electrolyte containing chrome glauber's salt is 23-30%, the concentration of chromium is 0.001-0.1 g / L; the concentration of sulfuric acid in the sulfuric acid anode liquid is 0-50 g / L; the concentration of sodium hydroxide in the sodium hydroxide cathode liquid is 0-80 g / L.

[0010] Preferably, in the step one, the volume ratio of the electrolyte containing chrome glauber's salt, the sulfuric acid anode liquid and the sodium hydroxide cathode liquid is 1:1-2:1-2.

[0011] Preferably, in the step two, before the electrolyte containing chrome glauber's salt is added into the middle cavity of the electrolytic cell of the three-chamber electrolytic device, the sound resonance mixing treatment is carried out, the process being: the electrolyte containing chrome glauber's salt is added into the sound resonance mixing tank, and under the conditions of vibration frequency of 30-160 Hz, vibration amplitude of 0.3-1 mm and temperature of 45-70℃, the vibration is carried out for 10-30 min.

[0012] Preferably, in the step two, the material of the electrolytic cell of the three-chamber electrolytic device is PVC or titanium; the anode plate is iridium-tantalum coated plate, and the cathode plate is stainless steel plate; the anode film is perfluorosulfonic acid type cation exchange film, and the cathode film is quaternary amine type anion exchange film.

[0013] Preferably, in the step two, the heating temperature is 45-70℃; the pump speed of the circulating pump is 35-50 L / h, and the current density is 1000-2000 A / m 2 .

[0014] Preferably, in the step two, during the electrolysis treatment, the ultrasonic cavitation treatment is carried out on the electrolyte containing chrome glauber's salt, the sulfuric acid anode liquid and the sodium hydroxide cathode liquid, the ultrasonic frequency of the electrolyte containing chrome glauber's salt being 60-80 KHz, the ultrasonic frequency of the sulfuric acid anode liquid being 30-40 KHz, and the ultrasonic frequency of the sodium hydroxide cathode liquid being 30-40 KHz; the ultrasonic treatment is carried out for 3-5 min, and then paused for 3-5 min, so as to carry out the cycle ultrasonic cavitation treatment; the ultrasonic power is 300-400 W.

[0015] Preferably, in the step three, during the electrolysis, the pH of the electrolyte containing chrome glauber's salt is 6-9, the alkaline substance for adjusting the pH is sodium hydroxide solution with mass fraction of 5-10%, and the acid substance for adjusting the pH is sulfuric acid solution with mass fraction of 5-10%.

[0016] Preferably, in the step three, the concentrations of the sulfuric acid anode liquid and the sodium hydroxide cathode liquid are controlled, the process being: when the concentration of sulfuric acid in the sulfuric acid anode liquid reaches 100-120 g / L, half of the sulfuric acid anode liquid is pumped out, and equal volume of pure water is pumped in for supplement; when the concentration of sodium hydroxide in the sodium hydroxide cathode liquid reaches 10-150 g / L, half of the sodium hydroxide cathode liquid is pumped out, and equal volume of pure water is pumped in for supplement.

[0017] Preferably, in the third step, when the chromium concentration in the electrolyte containing chrome glauberite reaches 80-100 g / L, the ionization is stopped.

[0018] The present application at least has the following advantages: the present application comprehensively utilizes sodium sulfate and chromium resources, and produces industrial raw material sodium hydroxide and sulfuric acid which can be reused for acidification of sodium chromate alkaline solution by electrolysis; the chrome glauberite is harmlessly disposed, the process is safe and environmentally friendly, and the production cost of enterprises is reduced.

[0019] Other advantages, objects, and features of the application will be apparent from the following specification and claims. DETAILED DESCRIPTION

[0020] The present application is further described in detail below, so that those skilled in the art can implement it according to the description.

[0021] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0022] <Embodiment 1>

[0023] A method for manufacturing sulfuric acid and caustic soda by electrolysis of chrome-containing glauberite in a three-chamber electrolysis device, comprising the following steps:

[0024] Step one, preparing an electrolyte containing chrome glauberite with a chromium concentration of 0.05 g / L and a sodium sulfate mass fraction of 25%, a sulfuric acid anode solution with a sulfuric acid concentration of 10 g / L, and a sodium hydroxide cathode solution with a sodium hydroxide concentration of 10 g / L; the volume ratio or mass ratio of the electrolyte containing chrome glauberite, the sulfuric acid anode solution and the sodium hydroxide cathode solution is 1:1:1;

[0025] Step two, adding the electrolyte containing chrome glauberite into the middle chamber of the electrolytic cell of the three-chamber electrolysis device, adding the sulfuric acid anode solution into the anode chamber of the electrolytic cell, and adding the sodium hydroxide cathode solution into the cathode chamber of the electrolytic cell; heating the three solutions to 60 DEG C; starting the circulating pump with a pump speed of 35 L / h; adjusting the current with a current density of 2000 A / m 2 The three-chamber electrolysis device is made of titanium material, the anode plate is iridium-tantalum coated plate, the cathode plate is stainless steel plate, the anode membrane is perfluorosulfonic acid type cation exchange membrane, and the cathode membrane is quaternary amine type anion exchange membrane.

[0026] Step 3: During electrolysis, adjust the pH of the chromium-containing sodium sulfate electrolyte to 8; control the concentrations of sulfuric acid anolyte and sodium hydroxide catholyte. When the sulfuric acid concentration in the sulfuric acid anolyte reaches 120 g / L, pump out half of the sulfuric acid anolyte and replenish it with an equal volume of pure water; when the sodium hydroxide concentration in the sodium hydroxide catholyte reaches 150 g / L, pump out half of the strong sodium hydroxide catholyte and replenish it with an equal volume of pure water; after ionization for 120 minutes, when the chromium concentration in the chromium-containing sodium sulfate electrolyte reaches 100 g / L, stop ionization, pump out the chromium-containing sodium sulfate electrolyte, and return it to the chromium salt leaching section for the recovery of chromium, aluminum, vanadium, and other resources; pump in freshly prepared chromium-containing sodium sulfate electrolyte and continue ionization.

[0027] <Example 2>

[0028] A method for electrolyzing chromium-containing sodium sulfate in a three-chamber electrolysis process to produce sulfuric acid and caustic soda includes the following steps:

[0029] Step 1: Prepare a chromium-containing sodium sulfate electrolyte with a chromium concentration of 0.05 g / L and a sodium sulfate mass fraction of 25%, a sulfuric acid anolyte with a sulfuric acid concentration of 10 g / L, and a sodium hydroxide catholyte with a sodium hydroxide concentration of 10 g / L; the volume ratio or mass ratio of the chromium-containing sodium sulfate electrolyte, sulfuric acid anolyte, and sodium hydroxide catholyte is 1:1:1.

[0030] Step 2: Add the chromium-containing sodium sulfate electrolyte to the acoustic resonance mixing tank and vibrate for 30 minutes at a vibration frequency of 60Hz, an amplitude of 0.5mm, and a temperature of 45℃. Add the acoustically resonated chromium-containing sodium sulfate electrolyte to the intermediate chamber of the three-chamber electrolysis unit. Add the sulfuric acid anolyte to the anode chamber of the electrolysis unit and the sodium hydroxide catholyte to the cathode chamber. Heat all three solutions to 60℃. Start the circulation pump at a speed of 35L / h and adjust the current to a current density of 2000A / m. 2 Electrolytic treatment is performed; in the three-chamber electrolysis equipment, the electrolytic cell is made of titanium, the anode plate is an iridium-tantalum coated plate, the cathode plate is a stainless steel plate, the anode membrane is a perfluorosulfonic acid type cation exchange membrane, and the cathode membrane is a quaternary ammonium type anion exchange membrane.

[0031] Step 3: During electrolysis, adjust the pH of the chromium-containing sodium sulfate electrolyte to 8; control the concentrations of the sulfuric acid anolyte and sodium hydroxide catholyte. When the sulfuric acid concentration in the sulfuric acid anolyte reaches 120 g / L, pump out half of the sulfuric acid anolyte and replenish it with an equal volume of pure water; when the sodium hydroxide concentration in the sodium hydroxide catholyte reaches 150 g / L, pump out half of the strong sodium hydroxide catholyte and replenish it with an equal volume of pure water; when ionization reaches 105 min and the chromium concentration in the chromium-containing sodium sulfate electrolyte reaches 100 g / L, stop ionization, pump out the chromium-containing sodium sulfate electrolyte and return it to the chromium salt leaching section for the recovery of chromium, aluminum, vanadium and other resources; pump in freshly prepared chromium-containing sodium sulfate electrolyte and continue ionization.

[0032] In step two of the embodiment, before the chromium-containing glauber's salt electrolyte is added to the middle cavity of the electrolytic cell of the three-chamber electrolysis device, the sound resonance treatment is carried out, which can make the mixing of chromium ions, sodium ions and sulfate ions in the electrolyte more uniform, and can make the subsequent ionization treatment more thorough and sufficient. Comparative example 1,

[0033] <Embodiment 3>

[0034] A method for manufacturing sulfuric acid and caustic soda by electrolysis of chromium-containing glauber's salt in a three-chamber electrolysis device, comprising the following steps:

[0035] Step one, prepare a chromium-containing glauber's salt electrolyte with a chromium concentration of 0.05 g / L and a sodium sulfate mass fraction of 25%, a sulfuric acid anolyte with a sulfuric acid concentration of 10 g / L, and a sodium hydroxide catholyte with a sodium hydroxide concentration of 10 g / L; the volume ratio or mass ratio of the chromium-containing glauber's salt electrolyte, the sulfuric acid anolyte and the sodium hydroxide catholyte is 1:1:1;

[0036] Step two, add the chromium-containing glauber's salt electrolyte to the middle cavity of the electrolytic cell of the three-chamber electrolysis device, add the sulfuric acid anolyte to the anode cavity of the electrolytic cell, and add the sodium hydroxide catholyte to the cathode cavity of the electrolytic cell; heat the three solutions to 60℃; start the circulating pump with a pump speed of 35 L / h; adjust the current with a current density of 2000 A / m 2 Step three, during the electrolysis process, adjust the pH value of the chromium-containing glauber's salt electrolyte to 8; control the concentrations of the sulfuric acid anolyte and the sodium hydroxide catholyte, when the sulfuric acid concentration in the sulfuric acid anolyte reaches 120 g / L, pump out half of the sulfuric acid anolyte and pump in an equal volume of pure water to supplement; when the sodium hydroxide concentration in the sodium hydroxide catholyte reaches 150 g / L, pump out half of the strong sodium hydroxide catholyte and pump in an equal volume of pure water to supplement; when the ionization time reaches 100 min, the chromium concentration in the chromium-containing glauber's salt electrolyte reaches 100 g / L, stop the ionization, pump out the chromium-containing glauber's salt electrolyte, return it to the chromium salt leaching section for recycling of chromium, aluminum and vanadium resources; pump in the newly prepared chromium-containing glauber's salt electrolyte and continue the ionization.

[0037] Step three, during the electrolysis process, adjust the pH value of the chromium-containing glauber's salt electrolyte to 8; control the concentrations of the sulfuric acid anolyte and the sodium hydroxide catholyte, when the sulfuric acid concentration in the sulfuric acid anolyte reaches 120 g / L, pump out half of the sulfuric acid anolyte and pump in an equal volume of pure water to supplement; when the sodium hydroxide concentration in the sodium hydroxide catholyte reaches 150 g / L, pump out half of the strong sodium hydroxide catholyte and pump in an equal volume of pure water to supplement; when the ionization time reaches 100 min, the chromium concentration in the chromium-containing glauber's salt electrolyte reaches 100 g / L, stop the ionization, pump out the chromium-containing glauber's salt electrolyte, return it to the chromium salt leaching section for recycling of chromium, aluminum and vanadium resources; pump in the newly prepared chromium-containing glauber's salt electrolyte and continue the ionization.

[0038] In step two of the embodiment, the electrolyte containing chrome mirabilite, the sulfuric acid anolyte and the sodium hydroxide catholyte are subjected to ultrasonic cavitation treatment while being subjected to electrolysis treatment. The cavitation effect of ultrasonic waves on the solution can cause liquid turbulence, strengthen mass transfer and improve the electrolysis reaction rate. In the comparative example 1,

[0039] <Example 4>

[0040] A method for manufacturing sulfuric acid and caustic soda by electrolysis of electrolyte containing chrome mirabilite in a three-chamber electrolysis device, comprising the following steps:

[0041] Step one: preparing the electrolyte containing chrome mirabilite with a chrome concentration of 0.05 g / L and a sodium sulfate mass fraction of 25%, the sulfuric acid anolyte with a sulfuric acid concentration of 10 g / L, and the sodium hydroxide catholyte with a sodium hydroxide concentration of 10 g / L; the volume ratio or mass ratio of the electrolyte containing chrome mirabilite, the sulfuric acid anolyte and the sodium hydroxide catholyte is 1:1:1;

[0042] Step two: adding the electrolyte containing chrome mirabilite into a sound resonance mixing tank, and vibrating for 30 min under the conditions of a vibration frequency of 60 Hz, an amplitude of 0.5 mm and a temperature of 45℃; adding the electrolyte containing chrome mirabilite subjected to sound resonance treatment into the middle chamber of the electrolysis tank of the three-chamber electrolysis device, and adding the sodium hydroxide catholyte into the cathode chamber of the electrolysis tank; heating the three solutions to 60℃; starting the circulating pump with a pump speed of 35 L / h; adjusting the current with a current density of 2000 A / m 2 Step three: during the electrolysis process, adjusting the pH value of the electrolyte containing chrome mirabilite to 8; controlling the concentrations of the sulfuric acid anolyte and the sodium hydroxide catholyte, pumping out half of the sulfuric acid anolyte and pumping in an equal volume of pure water to supplement when the sulfuric acid concentration in the sulfuric acid anolyte reaches 120 g / L; pumping out half of the sodium hydroxide catholyte and pumping in an equal volume of pure water to supplement when the sodium hydroxide concentration in the sodium hydroxide catholyte reaches 150 g / L; stopping the electrolysis when the chrome concentration in the electrolyte containing chrome mirabilite reaches 100 g / L after 90 min of electrolysis, pumping out the electrolyte containing chrome mirabilite and returning it to the chrome salt leaching section for recycling of resources such as chrome, aluminum and vanadium; and continuing the electrolysis by pumping in newly prepared electrolyte containing chrome mirabilite.

[0043] Step three: during the electrolysis process, adjusting the pH value of the electrolyte containing chrome mirabilite to 8; controlling the concentrations of the sulfuric acid anolyte and the sodium hydroxide catholyte, pumping out half of the sulfuric acid anolyte and pumping in an equal volume of pure water to supplement when the sulfuric acid concentration in the sulfuric acid anolyte reaches 120 g / L; pumping out half of the sodium hydroxide catholyte and pumping in an equal volume of pure water to supplement when the sodium hydroxide concentration in the sodium hydroxide catholyte reaches 150 g / L; stopping the electrolysis when the chrome concentration in the electrolyte containing chrome mirabilite reaches 100 g / L after 90 min of electrolysis, pumping out the electrolyte containing chrome mirabilite and returning it to the chrome salt leaching section for recycling of resources such as chrome, aluminum and vanadium; and continuing the electrolysis by pumping in newly prepared electrolyte containing chrome mirabilite.

[0044] In the second step of the embodiment, before the chromium-containing glauber's salt electrolyte is added into the middle cavity of the electrolytic cell of the three-chamber electrolysis device, the sound resonance treatment is carried out, so that the chromium ions, sodium ions and sulfate ions in the electrolyte are mixed more uniformly, and the subsequent ionization treatment is more thorough and sufficient. At the same time of the electrolysis treatment, the chromium-containing glauber's salt electrolyte, the sulfuric acid anode electrolyte and the sodium hydroxide cathode electrolyte are subjected to ultrasonic cavitation treatment. The cavitation effect of the ultrasonic wave on the solution can cause liquid turbulence, strengthen mass transfer and improve the electrolysis reaction rate.

[0045] The above description is merely preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A process for the manufacture of sulfuric acid and caustic soda by electrolysis of chrome mirabilite in a three-compartment electrolysis, characterized in that, The method comprises the following steps: Step 1, preparing a chromium-containing glauber's salt electrolyte, a sulfuric acid anolyte and a sodium hydroxide catholyte; The mass fraction of sodium sulfate in the chromium-containing glauber's salt electrolyte is 23-30%, and the chromium concentration is 0.001-0.1 g / L; the sulfuric acid concentration in the sulfuric acid anolyte is 0-50 g / L; the sodium hydroxide concentration in the sodium hydroxide catholyte is 0-80 g / L; the volume ratio of the chromium-containing glauber's salt electrolyte, the sulfuric acid anolyte and the sodium hydroxide catholyte is 1:1-2:1-2; Step 2, adding the chromium-containing glauber's salt electrolyte into the middle cavity of the electrolytic cell of a three-chamber electrolysis device, adding the sulfuric acid anolyte into the anode cavity of the electrolytic cell, and adding the sodium hydroxide catholyte into the cathode cavity of the electrolytic cell, heating the three solutions, starting the circulating pump, adjusting the current, and performing electrolysis treatment; the material of the electrolytic cell of the three-chamber electrolysis device is PVC or titanium; the anode plate is an iridium-tantalum coated plate, and the cathode plate is a stainless steel plate; the anode membrane is a perfluorosulfonic acid type cation exchange membrane, and the cathode membrane is a quaternary amine type anion exchange membrane; Step 3, adjusting the pH value of the chromium-containing glauber's salt electrolyte during the electrolysis process, and controlling the concentrations of the sulfuric acid anolyte and the sodium hydroxide catholyte; when the chromium concentration in the chromium-containing glauber's salt electrolyte reaches 80-100 g / L, stopping the electrolysis, pumping out the chromium-containing glauber's salt electrolyte, returning it to the chromium salt leaching section to recover chromium, aluminum and vanadium resources, pumping in the newly prepared chromium-containing glauber's salt electrolyte, and continuing the electrolysis; In step 2, before the chromium-containing glauber's salt electrolyte is added into the middle cavity of the electrolytic cell of the three-chamber electrolysis device, the chromium-containing glauber's salt electrolyte is subjected to sound resonance mixing treatment, and the process is as follows: the chromium-containing glauber's salt electrolyte is added into a sound resonance mixing tank, and is vibrated at a vibration frequency of 30-160 Hz, a vibration amplitude of 0.3-1 mm and a temperature of 45-70℃ for 10-30 min.

2. The process for manufacturing sulphuric acid and caustic soda in three compartments electrolysis of chrome-containing glauber salt electrolysis according to claim 1, characterized by, In the second step, the heating temperature is 45-70℃; the pump speed of the circulating pump is 35-50 L / h, and the current density is 1000-2000 A / m 2 .

3. The process for manufacturing sulphuric acid and caustic soda in three compartments electrolysis of chrome containing glauber salt as claimed in claim 1 wherein, In step 2, during the electrolysis treatment, the chromium-containing glauber's salt electrolyte, the sulfuric acid anolyte and the sodium hydroxide catholyte are subjected to ultrasonic cavitation treatment, wherein the ultrasonic frequency of the chromium-containing glauber's salt electrolyte is 60-80 KHz, the ultrasonic frequency of the sulfuric acid anolyte is 30-40 KHz, and the ultrasonic frequency of the sodium hydroxide catholyte is 30-40 KHz; the ultrasonic treatment is performed for 3-5 min, and is paused for 3-5 min, and the above process is repeated as a cycle; the ultrasonic power is 300-400 W.

4. The process for manufacturing sulphuric acid and caustic soda in three compartments electrolysis of chrome containing glauber salt electrolysis as claimed in claim 1 wherein, In step 3, during the electrolysis process, the pH value of the chromium-containing glauber's salt electrolyte is 6-9, the alkaline substance for adjusting the pH value is a sodium hydroxide solution with a mass fraction of 5-10%, and the acidic substance for adjusting the pH value is a sulfuric acid solution with a mass fraction of 5-10%.

5. The process for manufacturing sulphuric acid and caustic soda in three compartments electrolysis of chrome containing glauber salt electrolysis as claimed in claim 1 wherein, In step 3, the concentrations of the sulfuric acid anolyte and the sodium hydroxide catholyte are controlled, and the process is as follows: when the sulfuric acid concentration in the sulfuric acid anolyte reaches 100-120 g / L, half of the sulfuric acid anolyte is pumped out and an equal volume of pure water is pumped in to supplement; when the sodium hydroxide concentration in the sodium hydroxide catholyte reaches 10-150 g / L, half of the sodium hydroxide catholyte is pumped out and an equal volume of pure water is pumped in to supplement.