Oilfield Chemical Additive Calcium Bromide Brief Guideline 2020
Calcium Bromide Properties
Calcium bromide is a colorless oblique crystal or crystal block. It is odorless and tastes salty and bitter.The relative density of calcium bromide is 3.353 (at 25°C). The melting point is 730°C, and it is easy to decompose. The boiling point of calcium bromide is 806-812°C. It is very soluble in water.Calcium bromide can form double salt with alkali metal halides. It turns yellow in the open air for a long time.And it has strong hygroscopicity.
The role of calcium bromide in the drilling of oilfield chemicals
Calcium bromide is mainly used in oil drilling.It is also used to manufacture ammonium bromide and photosensitive paper, fire extinguishing agent, refrigerant, etc.It is used as central nervous depressant in medicine. Ferrous bromide is produced by the reaction of iron filings with bromine. Calcium bromide and its compound are mainly used in offshore oil drilling and completion fluid, cementing fluid and workover fluid.
Calcium bromide Solubility
The aqueous solution of calcium bromide is neutral. In addition, it is soluble in ethanol, acetone and acid. It is slightly soluble in methanol and liquid ammonia. Insoluble in ether or chloroform. Alkali metal, alkaline earth metal bromide and ammonium bromide are easily soluble in water. Insoluble bromides are similar to insoluble chlorides.
However, the solubility of the former is usually less than that of the corresponding chloride. The aqueous solution of hydrogen bromide is called hydrobromic acid. Hydrobromic acid is a strong acid. Metal bromides can be prepared by the reaction of corresponding carbonates or hydroxides with hydrobromic acid. Such as: sodium bromide, manganese bromide, barium bromide, copper bromide, magnesium bromide, thallium bromide, mercury bromide and so on.
Is calcium bromide a salt?
Calcium bromide (cabr2) is a salt. But its not very stable. Because calcium hydroxide is a weak alkali and hydrogen bromide is a weak acid.This salt formed by a weak acid and a weak alkali dissolves itself.Hydrobromic acid exists if its not in water. But once it is dissolved in water. Then there must be Ca2 +, Br -, oh -, and H + ions in the solution.
Calcium Bromide Preparation
1. Crystallization dehydration method.
55 ml 47% hydrobromic acid was diluted with 50 ml water. Stir and slowly add 20g calcium carbonate to the dilute solution. That is, CO2 is released and calcium bromide solution is formed.
Filter out insoluble impurities. The filtrate is heated and concentrated in a water bath. A layer of crystalline film is formed on the liquid surface. Stand still. Cool to room temperature. Calcium bromide hexahydrate crystallizes out. Suction filtration. Dry the crystal with filter paper. Then the calcium bromide hexahydrate was heated to its melting point (382°C) and dehydrated. Then increase the temperature to 50-60°C. Then the temperature was raised to 400°C. At the same time, the mixed dry gas of hydrogen bromide and hydrogen is introduced. Anhydrous calcium bromide can be obtained.
2. Ferrous bromide method.
Iron chips are added to the reactor containing water. Bromine was added in batches under stirring. The reaction was carried out at 40°C to produce ferrous bromide. Then add calcium hydroxide to adjust the pH value. Heat to boiling. After cooling and separation, ferrous hydroxide and calcium bromide were removed. The filtrate was evaporated and cooled to 30°C for standing. After decolorization, filtration and evaporation, the temperature was about 210°C. After cooling, calcium bromide was prepared.
3. Direct method.
Ammonia gas is introduced into the lime milk. Add bromine. The reaction was carried out below 70°C and filtered. The filtrate was kept in alkaline condition, and ammonia was expelled from the filtrate. The filtrate was concentrated to prepare calcium bromide.
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