SU697394A1 - Method of preparing ammonium fluoride - Google Patents

Description

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The invention relates to the field of fluoride production, in particular to the production of ammonium fluoride, including high qualifications, used in the electrical and electrical industries of the industry.

The presently used process for the preparation of high-purity ammonium fluoride by saturating hydrofluoric acid with gaseous ammonia is known. The obtained crystals are squeezed, dried In drying cabinets at 60-70 ° C and packed. The total production cycle (production of one batch of the product) is 61 hours. From this time, about 32 hours are spent at the stage of packing and packaging. Due to the long drying time, ammonium fluoride is hydrolyzed to ammonium bifluoride and ammonia. To prevent hydrolysis, drying is carried out in an ammonia atmosphere, thereby increasing its consumption.

A more intense method of producing ammonium fluoride, relative pa

degree of purity to class G, provides for the processing of the obtained crystals with gaseous ammonia at 100-110 C. This method allows to reduce the drying time somewhat. However, it is also periodic, associated with the use of manual labor, as well as with significant costs of gaseous ammonia, its subsequent capture and return to the process. This complicates the instrumentation of the process, leads to the formation of large volumes of ammonia-containing wastewater, accordingly, an increase in ammonia consumption, as well as higher heat and power consumption.

Consumption ammksh; g of ammonia WATER, according to a known method, is 9 tons per 1 ton of the FINISHED product.

The aim of the invention is to reduce the consumption of ammonia by excluding it from the drying process:

The goal is achieved by the proposed method of producing ammonium fluoride, which consists in the interaction of 3e; HII of hydrofluoric acid with ammonia, separation of crystals and their drying in this “„ 1 ”, liquefied layer with L- (so v. Heated by air with an initial temperature of 75-135 C for 2“ .4 min., Creating a developed surface (fluidized bed) contact of two phases at a temperature of corai -55-65 C and a short drying time prevents the hydrolysis of the Product and eliminates the use of ammonia at this stage of the product. At the same time, the total consumption of ammonia in ish, E 25% - ammonia water is reduced to 5, O22 tons per 1 ton of finished product. In addition, this method of obtaining flu ammonium ammonia reduces energy consumption, simplifies the instrumentation of the process, significantly improves the conditions for the production of ammonium fluoride. Depending on the degree of purification of the initial reagents, the invention can be used to produce ammonium fluorides of varying degrees of technical purity Cacti also use purified soafty. Intervals of drying parameters are determined from the conditions of optimal) НЬ1: from the expenses of heat, electric power, minimum overall dimensions of the entire equipment of the installation (upper and lower limits of the initial air temperature and drying temperature). They are due. also obtaining a conditioner product, on the one hand not subject to dissociation (upper limits of temperature and drying time, initial air temperature), and, on the other hand, containing the basic substance corresponding to the technical conditions for this product (lower limits of temperature and drying time, initial air temperature). Example. To obtain high purity ammonium (OFS qualification) B, 70 kg 38.5 -% is poured into the reactor | solution of hydrofluoric acid and with stirring saturate 15.87 kg of gas (5 ™ of various ammonia obtained from 25 ° C of ammonia water. Precipitation of the formed fluoride crystals at 18–2 ° C. The resulting pulp (85.87 kg after squeezing, 28 kg of ammonium fluoride with a 7% particle size of 0.57 is obtained. Salt is fed by a screw feeder in the amount of 26.4 kg / h continuously fed into the apparatus. Time x1 contact fluoride a 1 myi.y. 2.9 minutes by air through the chute of the apparatus; 1prepra 1 o dry heat / g t 2i3.75 kg / h dried product. Small fraction of fluoride-ammonium from the treated air is recovered in a cyclone in an amount of 0.5 kg / h. After cleaning the air, the air is exhausted to the atmosphere. The resultant content is 99.5% of the basic volume and corresponds to qualifikaci SAR on GI .827 ™ 76. Example 2. I get reactive ammonium fluoride (ChDA qualification) wasp; / is similar to Example 1. After . 27.4 kg of 5% moisture with a particle size of 0.6 mm are obtained. 74 kg / h of drodzkt are supplied continuously for drying. Drying is carried out analogously to Example 1. Air is supplied with an initial temperature of 100 ° C, the temperature in the layer of material is under 6 ° C, and the contact time of fluoride with air for 2 minutes. 64 kg / h was removed from the apparatus, and 5.5 from the cyclone of the finished product. The consumption of ammonia in the water of ammonia absorbed 5,022 kg pa 1 kg of the finished product. The resulting product contains 98.7% of the basic substance CNT and, respectively,: it is the qualification of the CHDA and GOSGG 4818-75. EXAMPLE 3 Preparation of technical ammonium fluoride (HC qualification) is carried out as in Example 1. After drying, 28.3 kg of salt with a moisture content of 8% and a particle size of 0.6 mm is obtained. 95 kg / h are continuously poured on for drying. . Drying is carried out similarly as in example 1. Air is supplied with an initial temperature, the temperature in the layer of material is maintained (contact time 11H) ammonium plaster with airflow for 4 minutes. An NP of kg / h is removed from the apparatus, and 8 kg / h of the cyclone, the finished prol. The flow rate of ammonia in the form of 25in ii;) ft pmmiach of water is o.iJ ..;: KJ- and / i i kg of the finished product.

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The resulting product contains 96.2% of the main) substances MU.dTk complies with the qualification of HCh according to GOST 4518-75,

The economic effect due to the reduction of ammonia consumption, energy consumption, production areas, operating costs is 90 thousand rubles per year with an ammonium fluoride production capacity of 120 tons per year.

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F o r Kf U l and invented to

 in the process of hydrofluoric ammonia, by reacting the melting acid with a carbonic acid, separating the crystals and cyuf ki with a gaseous coolant, so that, in order to reduce the consumption of ammonia, drying is carried out in the outer layer at 55 65 WITH ME. and as a gaseous carrier, air is used with an initial temperature of 7 5-13 5.