The principle of extracting bromine from seawater! Write out chemical equations

In seawater, there are few bromine elements, mainly in the form of metal bromides (Nabr, Mgbr2...).The industrial bromine extraction adopts the displacement method, the hot air blows the gas out of the lye and then absorbs it, and the sulfuric acid acidification and then extracts it is combined, and the specific equation is as follows [take Nabr as an example] 2Nabr + Cl2 = 2NaCl + Cl2

3br2+6na2co3+3h2o=5nabr+nabro3+6nahco3

5Nabr + Nabro3 + 3H2SO4 = 3Na2SO4 + 3BR2 + 3H2O [gas label for gas generation] The main process is like this, of course, there are also NaOH instead of Na2CO3 to absorb Br2.

Well, hope it helps.

Air blowing method is a common method used for industrial-scale seawater bromine extraction, one of the processes is to replace bromine ions with chlorine in pre-acidified concentrated seawater to make it into elemental bromine, and then introduce air and water vapor to blow bromine into the absorption tower, so that the bromine vapor and the absorbent sulfur dioxide interact and convert into hydrobromic acid to achieve the purpose of enrichment, that is, to obtain enriched bromine. It is then oxidized with chlorine to obtain product bromine.

The main chemical reaction equation is air blowing method: 2Nabr+Cl2===br2+2NaClbr2

so22h2o=2hbr

h2so4cl2

2hbr=2hclbr2

1. Chlorine gas is introduced into the pre-acidified concentrated seawater, 2br +cl2=2cl +br22, and the air is blown out of the stuffy method, and air and water vapor are introduced.

Blowing the bromine element out of the seawater is pure none.

3. The bromine steam blown out is absorbed by the absorption tower to make the bromine steam br2 + so2 + 2h2o = 2 hbr + h2so4

and the absorbent SO2 in the absorption tower This is the enrichment process.

4. Finally, HBR (hydrobromic acid) is oxidized with chlorine to obtain the bromine elemental 2HBR+Cl2=BR2+2HCl

The method of extracting bromine from seawater is as follows: the seawater concentrated after distillation (to freshwater) is acidified with sulfuric acid; into acidified seawater.

Sufficient amount of chlorine is concealed.

The bromine ion is converted into bromine element, and the equation is: 2Nabr+Cl2=br2+2NaCl

Air and water vapor are introduced into the above solution, and the bromine elemental is blown into the sulfur dioxide content.

The aqueous solution is converted into hydrobromic acid in the absorption tower, and the equation is: BR2+SO2+2H2O=2HBR+H2SO4 An appropriate amount of chlorine is introduced into the absorption tower, and the equation is: 2HBR+CL2=2HCl+BR2 The bromine element in the absorption tower is extracted with carbon tetrachloride.

Method for extracting sensitive bromide from seawater: Chlorine gas is introduced.

The bromide in the concentrated solution is oxidized and the resulting bromine is blown out with air; The bromine blown out was absorbed by Na2CO3 to dissolve and leak branches, and Nabr and Nabro3 were generated at the same time to release CO2. Sulfuric acid solution was added to the solution containing bromide (Nabr, Nabro3), and the bromine was re-precipitated to form Na2SO4 at the same time; The resulting bromine may be mixed with chlorine, and Febr3 (a displacement reaction occurs.

Remove. Corresponding chemical equations.

cl2+2nabr=2nacl+br2

2febr3+3cl2=3br2+2fecl3

The general process is like this:

In the first step, chlorine gas is introduced into the seawater to oxidize the bromine ions to bromine element

cl22br-

2cl-br2

Step 2: The resulting bromine is blown out of the clump with air, absorbed with an alkaline sodium carbonate solution, and the bromine is disproportionated into br- and bro3-:

3br23na2co3

5nabrnabro3

3CO2 first three steps: add excess acid dropwise to the solution, and Br- and Bro3- undergo a neutralization reaction to regenerate bromine.

bro3-5br-6h+

3br23h2o

The method of extracting bromine from seawater is as follows:

Acidification of seawater concentrated after distillation (freshwater) with sulfuric acid;

Sufficient amount of chlorine is introduced into the acidified seawater to convert bromine ions into bromine element, the equation: 2Nabr+Cl2=br2+2NaCl

Air and water vapor are introduced into the above solution, and the bromine element is blown into the absorption tower containing sulfur dioxide aqueous solution and converted into hydrobromic acid, and the implicit formula is: br2 + SO2 + 2H2O = 2HBR + H2SO4

An appropriate amount of chlorine is introduced into the absorption tower, and the equation is: 2HBR+CL2=2HCl+BR2

Extraction of bromine elements from the absorption column with carbon tetrachloride.

1. In the process of salting and desalination, the by-product bromine is concentrated.

2. Chlorine gas is injected into the concentrated bromine, and Youpei oxidizes the bromine to liquid bromine.

3. Using the volatility of liquid bromine, inject hot air and water vapor, and after the injection is completed, the liquid bromine will evaporate the bromine vapor and absorb the bromine vapor with sulfur dioxide.

4. Hydroxide bromide is oxidized with liquid slag bromine to obtain bromine element.

The process and equation of seawater bromine extraction are as follows:

1. Chlorine gas is introduced into seawater to oxidize bromine ions into bromine element: Cl2+2BR-==2Cl-+BR2

2. The generated bromine is blown out with air, absorbed with alkaline sodium carbonate solution, and disproportionated into br- and bro3-:3br2+3na2CO3==5nabr+nabro3+3CO2

3. Excessive acid is added to the solution with lead, and br- and bro3- are neutralized to regenerate bromine: bro3-+5br-+6h+==3br2+3h2o

The introduction of seawater bromine is as follows:

Since bromine exists in an ionic state in seawater, in the process of extracting bromine, the raw seawater is first acidified, and then oxidized to bromine by chlorine or other oxidants, and then the bromine is chemically separated from the mother liquor. At present, seawater bromine extraction technology includes air blowing method, steam distillation method, solvent extraction method, precipitation method and adsorption method, among which air blowing method is widely used in industry.

This method is to use chlorine to oxidize the bromine ions in seawater to make it into bromine, and then introduce air or water vapor to blow the bromine out, and the whole process includes acidification, oxidation, blowing, absorption and distillation. With this method, there is less equipment, simple processes, and easy mechanization and automation.

In the modern seawater extraction industry, all bromine extraction processes are controlled and documented using an automatic control system. At present, the United States, the United Kingdom, Germany, France and Japan have successively established seawater bromine extraction plants. The United States built the world's largest seawater bromine extraction plant during World War II, which at that time produced almost 2 3 percent of the world's total seawater bromine.

China's research and development of seawater bromine extraction technology began in the mid-60s, in 1968 the use of air blowing method from seawater direct bromine extraction test success, in Qingdao, Lianyungang, Beihai and other places have established an annual output of 100 tons of seawater bromine extraction plant for trial production. At present, the main methods used in China are steam distillation and air blowing.

Naturally occurring forms and preparations.

The diatomic molecule of bromine, Br2, does not occur naturally, and bromine is mainly dispersed in the earth's crust in the form of bromine salts. By filtration, the bromine salt content in seawater is about 65 ppm, and its concentration in the sea is smaller than that of chlorine. Bromine can be mined commercially in bromine-rich brine wells and in the Dead Sea (close to 50,000 ppm).

In 2007, nearly 556,000 metric tons (worth about $2.5 billion) of bromine were manufactured, with the most important producers being the United States, Israel and China. Bromine production has grown sixfold since the 1960s, with the highest levels of bromine in the United States occurring in Columbia and Juignan. China's bromine** is located in Shandong Province, while Israel's bromine originates from the waters of the Dead Sea.

Chlorine is used to treat bromine-rich brines, in which the bromine ions are oxidized by the chlorine gas to form bromine molecules. Due to the commercial use of bromine and its long shelf life, people do not deliberately prepare it. However, small amounts of bromine can be prepared from solid sodium bromide and concentrated sulfuric acid (H2SO4).

The first step of the reaction is the production of gaseous hydrogen bromide (HBR), but under this reaction condition, part of the hydrogen bromide is further oxidized by sulfuric acid to form bromine molecules (BR2) and sulfur dioxide (SO2). Nabr (S) +H2SO4 (AQ) HBR (AQ) +NaHSO4 (AQ)2 HBR (AQ) +H2SO4 (AQ) BR2 (G) +SO2 (G) +2 H2O (L) It is also possible to use similar compounds, such as dilute hydrochloric acid and sodium hypochlorite. Most importantly, the acid's anions (in the example above, sulfate and chloride) are more electronegative than bromine, allowing substitution reactions to occur.

(1) Chlorine gas is introduced into the concentrated brine.

Cl2 + 2br-= br2 + 2cl-(2) Br2 is blown out with hot air and 3br2 + 3Na2CO3 = 5Nabr + NaBro3 + 3CO2 is absorbed with sodium carbonate solution

3) Acidification with sulfuric acid.

5nabr + nabro3 + 3h2so4= +3na2so4+3br2 + 3h2o

Final distillation**.

First, the enrichment is carried out, the bromine ion and chlorine are reacted with hot air and blown out with sulfurous acid solution to absorb, chlorine is added to the obtained solution and then extracted, and then distilled.

1.Acidificationseawater, add dilute sulfuric acid 2Chlorine gas passBromine ions are oxidized to bromine elementals in seawater at pH.

cl2 + 2br- = 2cl- +br23.with compressed airBlow out br2and inDisproportionation under alkaline conditions

br2 + 3co32- = 5br- +bro3- +3co2↑4.Concentrate the solution, inNeutralized under acidic conditionsto produce bromine element.

5br- +bro3- +6h+ = 3br2 + 3h2o