SU1038282A1 - Process for producing lithium bromide - Google Patents

Abstract

1. A METHOD FOR OBTAINING BROMIST LITHIUM, which includes treating a suspension of lithium carbonate with liquid bromine in the presence of an inorganic reagent, followed by separating the solution from the precipitate, evaporation and crystallization of the product from it, so that in order to reduce the cost of the process while maintaining the yield and content of the main substance in the product, as the inorganic reagent use aluminum and water, 2. Method according to claim 1, characterized in that ammonia water is taken with a concentration of .25-30%, 3, Pop method . 1, characterized in that the treatment with liquid bromine is first carried out at a rate of 6Q-90 l / h to contain 60-90 g / l / l in the reaction mass of lithium carbonate and then at a speed of 30-50 l / h until no lithium carbonate is present. ko

Description

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The invention relates to chemical technology of inorganic substances, in particular, to methods for producing lithium bromide, which can be used to prepare the working solution of refrigerators used in the chemical, metallurgical and other industries.

A method of producing lithium bromide is known by reacting lithium hydroxide with hydrobromic acid 11.

The disadvantage of this method is the high cost of the process associated with the use of expensive reagents - lithium hydroxide and hydrobromic acid.

The closest to the present invention is a method for producing lithium bromide, which includes treating a suspension of lithium carbonate suspension with a ratio of p-5) liquid bromine in the presence of 7-40% hydrogen peroxide at 15-50 ° C with stirring, followed by separating the solution from 25 sludge its evaporation and crystallization of the product from it 2.

The disadvantage of this method is the high cost of the process associated with the use of expensive hydrogen peroxide (the cost of raw materials per ton of product is 3,551 rubles).

The purpose of the invention is to reduce the cost of the process while maintaining the yield and maintaining the main substance in the product (the cost of raw materials per ton of product decreases by 135 rubles).

This goal is achieved in that according to the method of producing lithium broth, which involves treating a suspension of lithium carbonate with liquid bromine in the presence of an inorganic reagent, followed by separating the solution from the precipitate, evaporating it and crystallizing the product from it, 45 and using ammonia water as the inorganic reagent.

Moreover, ammonia water is taken with a concentration of 25-30% and treatment with liquid bromine is first carried out at a speed of 60-90 l / h until the content of lithium carbonate in the reaction mass is 6090 g / l, and then at a speed of 3050 l / h lithi.

The method is carried out as follows.

Aqueous suspension containing (3-5) lithium carbenate is brominated with liquid bromine in the presence of 2530% ammonia water at a temperature of 15–55 C.

Bromination lead in two stages.

The first stage of bromination proceeds by reaction.

ЗЫВСО + ЗВг + 2КН б1ЛВг + ЗСО + N + ЗН О (1

The carbon dioxide released in reaction (1) reacts with dissolved ammonia and forms ammonium carbonate, which precipitates

in the net.

2NH, (p) (.. +% 0- (NH4), COj.

At the second stage, ammonium carbonate formed in the first bromination stage is used as a reducing agent and bromination proceeds with a rapid release of carbon dioxide by the reaction

3Li, CO, + 3Br + (NH..L С0, LiBr +

- About 4- 2 p

 . + 4C02 + N ,.

Bromination is carried out until the absence of lithium carbonate in the solution, which is determined visually by the yellowing and transparency of the solution.

The feed rate of bromine in the first bromination stage is controlled by the temperature of the reaction mass. I An increase in the bromination rate above 90 l / h leads to an increase in the temperature of the reaction mass above, which in turn leads to a significant loss of bromine, ammonia and decomposition of ammonium carbonate.

The feed rate of bromine in the second bromination stage is controlled by foaming of the reaction mass as a result of the rapid release of carbon xyloxide.

An increase in the bromination rate in the second stage above 50 l / h leads to a strong foaming of the reaction mass, as a result of which the reaction mass may be released from the apparatus.

Reducing the feed rate of bromine in the first stage is less than 60 l / h, in the second stage less than 30 l / h leads to a decrease in the productivity of the apparatus.

When the lithium carbonate suspension is brominated, the reaction mass is very thick due to the precipitation of ammonium carbonate, which leads to uneven mixing and release of bromine from the reaction mass.

Bromination of a lithium carbonate suspension leads to the preparation of weak solutions for the content of lithium bromide, and this reduces the performance of the equipment and increases energy consumption.

The use of ammonia water with an ammonia content of less than 25% leads to a decrease in the productivity of the apparatuses due to dilution of the reaction mass and an increase in energy consumption, and above 30% to the formation of a thick reaction mass and emissions of A1 1 1ac and I bromine. The resulting lithium bromide solution is adjusted to pH 10 by adding lithium hydroxide, if necessary, rectified from impurities, filtered, evaporated to boiling point. The pulp is cooled before and the center is fughened. If necessary, using lithium bromide in the form of a solution, final evaporation is given to a density of 1.515-1.540 g / cm (measured at. Example. In a 1.5 L round-bottom flask equipped with a stirrer , a thermometer and a bromine dispenser, place 600 ml of distilled water, then with stirring 200 g of lithium carbonate and 145 ml of 25% ammonia water. Bromination is carried out with liquid bromine at the temperature of the reaction mass. After 80 ml of bromine starts foaming the reaction mass after Carbonation is carried out until there is no lithium carbonate in the solution, which is determined visually. The solution should be clear and slightly yellow. The amount of bromine per reaction is 1 volume per 1.03 volumes of 25% ammonia water. Bromination in the first stage of the reaction is 60 l / h, in the second stage - 30 l / h. At the end of the reaction, a suspension of lithium carbonate is added to the bleaching and lithium hydroxide to pH 10 in order to obtain lithium bromide not containing ammonium ions, then evaporated to 115 .. S. P If necessary, the sulfates are precipitated with a saturated solution of barium hydroxide. Next, the lithium bromide solution is filtered through a dense filter, transferred to a porcelain dish, and the final preparation is carried out until the boiling point of the solution is 170 ° C. The lithium bromide pulp is cooled with slow stirring up to 28 s. Then it is filtered through a paper filter on a Buchner funnel. The resulting lithium bromide double-water crystals are placed in a bank with a ground stopper. The mother liquor is used by adding it to the reaction mass after bromination. Yield 620 g Example2. Into a round-bottom three-neck flask with a capacity of 2 liters, equipped with a stirrer, thermometer, and dose of bromine, 800 ml of distilled water are placed, then, with stirring, 200 g of lithium carbonate and 134 m of 27% ammonia water. Bromination is carried out with liquid bromine at the reaction temperature (Lassa. After 80 ml of bromine is supplied, foaming of the reaction mass begins as a result of carbon dioxide evolution. Bromination is carried out until there is no lithium carbonate in the solution, which is determined visually. The solution should be transparent and slightly yellowish. The amount of bromine per reaction is 1 volume per 0.96 volume of 27% ammonia water. Bromine feed rate at the first bromination reaction stage 75 l / h, at the second stage - 40 l / h. At the end of the reaction lithium carbonate suspension is added until decolorization and lithium hydroxide to pH 10, to obtain lithium bromide, not containing ammonium ions, then evaporated to. If necessary, the sulfates are precipitated with a saturated solution of barium hydroxide. Next, the lithium bromide solution is filtered through a dense filter, transferred to a porcelain mixture. and carry out the final caking to a density of 1.515 g / cm (measured at). When the round-bottom three-necked flask with a capacity of 2 liters, equipped with a stirrer, a thermometer and a bromine dispenser, is placed, place 1000 ml of distilled water while stirring, 200 g of lithium carbonate and 123 ml of 30% ammonia water. Bromination is carried out with liquid bromine at. After supplying 80 ml of bromine, foaming of the reaction mass is initiated due to carbon dioxide evolution ... Bromination is carried out until the absence of lithium carbonate in the solution, determined visually. The solution should be clear and slightly yellow. The amount of bromine per reaction is 1 volume per 0.88 volume of 30% ammonia water. The feed rate of bromine in the first bromination stage is 90 l / h in the second stage — 50 l / h. After the completion of the reaction, lithium carbonate is added until bleaching and lithium hydroxide to pH 10, in order to obtain lithium bromide, which does not contain: ammonium ions, then evaporated to. If necessary, the sulfates are precipitated with a saturated solution of barium hydroxide. Next, the lithium bromide solution is filtered through a dense filter, transferred to a porcelain dish, and the final evaporation is carried out to a density of 1.540 g / cm (3aMej} is performed with IOS).

 1038282

The proposed method allows i while maintaining the yield and reduces the process by reducing the holding of the main factor in raw materials costs by J. of 135 rubles. product.

Claims (3)

1. METHOD FOR PRODUCING BROWN LITHIUM, including treating a suspension of lithium carbonate with liquid bromine in the presence of an inorganic reagent, followed by separation of the solution from the precipitate, its evaporation and crystallization of the product from it, which is ensured by the fact that, in order to reduce the cost of the process while maintaining the yield and content of the main substance in the product, ammonia water is used as an inorganic reagent. 2. The method of pop. 1, characterized in that ammonia water is taken with a concentration of 25-30%. 3. The method of pop. 1, characterized in that. The treatment with liquid bromine is carried out first at a speed of 60-90 l / h until the content in the reaction mass of lithium carbonate is 60-90 g / l, and then at a speed of 30-50 l / h to the absence of lithium carbonate . >