PL158809B1 - Method for preparation of calcium carbonate, especially for pharmacy - Google Patents

Abstract

A method of obtaining calcium carbonate, particularly for the needs of pharmacy, characterized in that the post-distillation liquid from which the excess of sulfate ions has been removed and which contains 0.80-1.15 mole/dm<3> of calcium chloride, and a solution of sodium bicarbonate from which iron ions have been removed and which contains 0.70-1.30 mole/dm<3> of sodium bicarbonate are introduced simultaneously with intensive stirring to mother liquor or to a suspension containing 7-20 percent by weight of calcium carbonate crystals, at a temperature between 293 and 323 degrees K, and further the obtained calcium carbonate suspension is subject to the counter-current repulping process with the use of industrial condensates from soda manufacturing, and further the washed precipitate is centrifuged and dried at the temperature of 383 degrees K.

Description

The subject of the invention is a method of producing calcium carbonate, especially for pharmaceutical purposes.

There is known from the patent description No. 153,154 a method of producing calcium carbonate for tablets, which consists in reacting a pre-purified distillation liquid from the baking soda process with pre-purified sodium bicarbonate.

The disadvantage of this method is to obtain a high rock load by grinding the calcium carbonate. This causes its clumping during storage.

The aim of the invention is to develop a method for the production of calcium carbonate using waste fluids from the production of soda by the ammonia method and ensuring a product of high purity and high bulk density without the need for grinding.

The method according to the invention consists in the fact that the pcdessylation fluid containing 0.80 - 1.15 imol / dm of calcium chloride is purified from the excess of Siβr · Cairtic ions and purified from 3

Iron ions, an aqueous solution of sodium bicarbonate containing 0.70 - 1.30 mol / dm of aodium bicarbonate, is simultaneously introduced into the mother liquor or the suspension containing 7 - 20% by volume of calcium carbonate crystals, under intensive stirring. The precipitation process is carried out at the temperature of 293 - 323 K. Then the obtained calcium carbonate suspension is subjected to a counter-current repulpation process with the use of industrial condensates from the production of soda, then the washed sludge is centrifuged and dried at 383 K.

Surprisingly, it was found that the introduction of the mother liquor containing 7 - 20% ^of BJE ^t ościowych embryos krystalizacyinych calcium carbonate to the reaction mixture, consisting of the liquid distiller 1 solution of sodium bicarbonate Aodu affects not only on the growth of its crystals, but primarily lc ^ howy part compact buildings, having a significant impact on the increase of the bulk and shock weight.

158 eo9

In order to ensure the continuity of the precipitation process and to obtain the desired product parameters, the reaction medium is returned to the reaction medium at a certain rate with the concentrated calcium carbonate suspension from the decanting operation. The distillation fluid purifies excess sulfate ions in a known manner by co-precipitating them with a suspension of calcium hydroxide, carbonizing them and separating the precipitate by filtration. On the other hand, an aqueous solution of sodium bicarbonate is purified from iron ions in a known manner, with still distillation fluid purified from thicctric ions through their adsorption on the surface of precipitating calcium carbonate. As industrial condensates, they are used with brewed water from the condensation of process gases in the ammonia regeneration unit.

Due to the use of the complete introduction of crystalline nuclei into the precipitation process, the method according to the invention allows for any desired physicochemical properties of calcium carbonate to be shaped. On the other hand, the use of reagents purified from excess siaccannate and iron ions and the additional introduction of countercurrent ummilioiα pulp to obtain a high purity carbonate meeting farm requirements. Moreover, an advantage of the method according to the invention is the utilization of the distillation fluid and mother liquor, which constitute a waste that is burdensome for environmental protection in the production of soda by the amoit method.

The method according to the invention, without limiting the scope of its protection, is illustrated in more detail by the following examples.

EXAMPLE 1 0.2 m3 of a caustic liquor containing submlLkrono ^ ^ size nuclei are introduced into a 1.5 m3 thermostatic reactor equipped with a stirrer, and then simultaneously 0.611 m3 of distillation fluid are dosed over 0.5 hour. with a concentration of 1.07 mol / dm calcium ions and a content of 0.14 g / dm sulfur clan ions and 0.5 m3 of toltwirL ¹ sodium bicarbonate purified from ferric ions with a concentration of 3 carbonate ions 1.12 mol / dm, in inch cleaning the excess still liquid

3

Thiaicate ions are introduced into 1 m of this fluid at a temperature of 353 K with 10 dm of hydroxide suspension with a concentration of 4 moles / dm, and then subjected to the carbonization process until complete turbidity. The Y / precipitate is removed on a bag filter, and a clear solution of τ containing 0.14 g / dm3 of thionium ions is directed to the precipitation process. However, in order to 3 purify the sodium bicarbate solution from iron ions, up to 1 m of this solution with a concentration of 3 3

1.12 moles / dm of carbonate ions are introduced into 0.2 m of the distillation fluid, previously purified of sulfurate ions, with a concentration of 1.07 moles / dm of calcium ions. The warm calcium carbonate suspension is subjected to the process of napowOaθzαniα in order to oxidize ferrous ions and their adsorption on the developed surface of calcium carbonate crystals, and then it is passed through

With a flaring fabric, obtaining a clear solution with a content of less than 0.001 mol / dm of iron ions. The carbonate precipitation process is carried out at a temperature of 313 K. The oily suspension of calcium carbonate is kept in the reaction environment for a period of 0.4 hours, and then directed to a multi-stage, anti-current repulpacci, where by means of condensates from the condensation of technological gases in the ammonia regeneration unit removes solid phase impurities. The concentrated ClO2 solution is then filtered with the calcium carbonate suspension and the resulting precipitate is dried at 383K. Part of the mother liquor is returned to the lime carbonate precipitation process. There is obtained calcium carbonate with a gravity of 1143 g / dm 3 and -2-3+ ion content: Cl - 0.00% by weight, SO ₄ - 0.0% by weight and Fe - 0.004% by weight.

Example II. As in Example 1, 0.25 m 3 1% of a solid containing 16% by volume of carbonate crystal is introduced, and then dosed over the course of

3

0.5 hours at the same time 0.367 m of still fluid with a concentration of 1.13 mol / dm of calcium • 3 3 ions and the content of less than 0.14 mole / dm of βlajcaan ions and 0.675 No. of aqueous solution

3 sodium bi ^^ onate with a target of 1.22 mol / dm of carbonate ions and a content of 0.002 mol / dm of iron ions. The precipitation process is carried out at a temperature of 293 K. Powesela is kept in the calcium carbonate suspension for 0.4 hours while still in the reaction medium, and then sent to a multi-stage, counter-current pulpacc, where by means of condensates; that

15Θ 809 process gas condensation in the ammonia regeneration unit removes impurities in the solid phase. Part of the suspension thus purified is returned to the precipitation process, and the remainder is filtered. The obtained sediment is dried at the temperature of 383 K, obtaining calcium carbonate with a tremble weight of 1112 g / dm3 and the content of Cl ions - 0.00%

2 _- 3+ by weight, SO ^ - ^ 0.0% by weight, and Fe - 0.004% by weight.

Department of Publishing of the UP RP. Circulation of 90 copies

Price PLN 5,000.

Claims (4)

Patent claims 1. Method for the production of calcium carbonate, especially for the needs of the pharmaceutical industry, characterized in that the replacement fluid, purified from excess sulfate ions, containing 0.80 - 1.15 mol / dm of calcium chloride and purified from iron ions, 3 aqueous sodium bicarbonate solution containing 0.70 1.30 mol / dm sodium bicarbonate is simultaneously introduced into the mother liquor or a suspension containing 7 - 20% by volume calcium carbonate crystals at a temperature of 293,323 K under continuous stirring, and then the obtained calcium carbonate suspension is processed countercurrent repulpation with industrial condensates from soda production, then the washed sludge is centrifuged and dried at 383 K, The method according to claim 1, characterized in that the distillation fluid is cleaned of the excess sulfur ions in a known manner by co-screwing them with a calcium hydroxide suspension, carbonization and separation of the precipitate by filtration. 3. A method according to claim 1, characterized in that the sodium is purified from iron ions in a manner known per se in the distillation fluid by adsorbing them with calcium. The result is that an aqueous solution of bicarbonate is purified from sulfate ions on the surface of carbonate crystals 4. The method according to claim 1, characterized in that the industrial condensates used are water resulting from the condensation of process gases in the ammonia regeneration unit.