SU781194A1 - Method of producing dustless potassium fertilizers - Google Patents

Description

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The invention relates to the production technology of dust-free potassium chloride in the processing of sylvinite ores by the method of dissolution-crystallization .5

Methods are known for the preparation of enlarged crystals in so-called adjustable vacuum crystallisation apparatus, the most promising of which are considered to be methods for the preparation of large-crystalline products in apparatus with circulating suspension. The volume of such devices per 1 ton of production is 4-5 times higher than the volume of conventional multistage vacuum crc-15 thallion units. One or more high-power electric motors are installed to create power supply modes for the crystals and circulate the suspension to the coycid of the devices. 20 and the power consumption in these installations is many times greater than the energy consumption for obtaining potassium chloride in conventional vacuum crystallization installations l.25

However, in controlled vacuum crystallization plants, 2-4% of the crown fractions are obtained, which are removed from the process and, therefore, the problem of disposal of this dust arises. The widespread use of ko1 «1lex and mixed fertilizers requires that the potassium chloride used for their preparation does not have dust particles and has a very good flowability, which is ensured by accurate dosages1 (the grain size of the mixed fertilizers should be within 0.25-1.0 mm or have even more ek range of size.

The closest to the present invention is a method for obtaining dust-free potash fertilizers, in which crystallization of improved particle size distribution is obtained in conventional multi-stage vacuum crystallization plants by means of a double classification of the entire crystallization into three fractions. The coarse and fine fractions are separated from the process, but, and the average is returned to the vacuum crystallization plant (VCC) in the form of a suspension.

In another embodiment, the crystallization of multistage VKU B is carried out in two stages. At the first, salts of amines are introduced into the solution, and at the second, lead salts, the crystallization is carried out after the first stage with the return of fine fractions after they are dehydrated on the filters to the beginning of installation 2. One; this solution completely does not solve . Lenno product. In the first version, along with large RpHCTaJiJiHsafdM, a fine crystallisate (5%) is obtained, which requires separate filtering and drying equipment (baths and solving the problems of using a dusty product. In another version, adding to the solution of amine and lead salts after the second stage of crystallization) ftpoks will inevitably lead to clogging of the enlarged product by dust fractions; in the process of filtration of crystallisate, the wet matter is impregnated with the raw material. The liquor is dipped in salt 14 from the solution to Figure 1: Scrubbing in the form of dust fractions m smvmrm iK € vr-w-Km.NaCt / КСг. In addition, crystallization occurs during the drying process, which ultimately leads to clogging of the product by a dust-like fraction. . „.„ SKK iif :::: - r Qiznb zo) (from: & nch - developed1 and sbba, which allows to obtain high-quality. InfraredUkt of enlarged-granulometric composition of 0.2-0-0.6 m in installations of ordinary a vacuum crystal of the Shtisch pyleysh ut Shizirs dust fraction. The goal is achieved by using the well-known method of obtaining dust-free potassium fertilizers by processing syVyMyvyyyd ores by dissolving with a vydelyyyyyyy cheliryuyuyyyyyyyyyyyuyuyuyu jyuyyyyyyyyyuyuk law department in which you will be able to get a multi-solution of polystyrene by vacuum crystallization and return to one of the factions. Sug: a grade with saturation degree of a solution of sodium chloride 0.97-0.98 with a subsequent classification of the solid phase into cruciferous and fine-crystalline products, separation of them from the suspension, etc. Coy macrocrystalline produ: one drying, dust removal, the dust fractions obrabot Coy yPbShvratom water together with the washings from the major fractions crystal tion process, obrabot Coy melk6kistayliches one product water and acute prrm yOLuchoniem slurry temperature. 90-100 ° C and the last feed to the solution before vacuum crystallization. Example. According to the proposed method, the crystallization of the CS is carried out in a multistage horizontal vacuum-crystallization installation with - last-stage study | GYSTSHY SUSPUS SUSPENDED 3 AI , 98), which fully guarantees the obtaining of a crystalline crystal containing only the CS. From the resulting suspension, the large-slurry fraction is separated by hydroclassification, condensing the suspension in a sump with a certain upward flow rate. The classification is carried out in the size range of 0.2-0.6 mm. The condensed suspension of the coarse-crystalline product is filtered, washed on the filter (centrifuge) with cold water, dried, the dust fractions are separated by air classification in the KflaecdiB range of 0.2-0.6 mm and the dust-free KS is sent to the finished product warehouse. After the separation of the coarse crystallisate from the combined solution-drain of the settling tank and the Filtrate, fine fractions are separated, thickening the suspension in the settling tank and then filtering it. The mother liquor is returned to the dissolution of sylvinite. Filtered crystalline potassium chloride is mixed with water from washing the coarse-crystalline product, treated with hot water and live steam to form a suspension of 90-100 C. Dust the dried hot product fractions treated with hot water and, together with the suspension of crystalline potassium chloride, is directed to mixing with the mountains chemical solution supplied to crystallization. To prevent possible crystallization of sodium chloride fr, a small amount of hot water is added to the latter by mixing the suspension of crystallisate with hot liquor after dissolving. The proposed method allows to obtain dustless potash fertilizers at low levels under the range of 0.2-0.6 when returning to crystallization of finely dispersed potassium chloride in the amount of 20-80% of the finished product. PRI me R. On crystallization, the hot () clarified solution of pb & le solution of sylviyita comes in, its composition is,%: KCl 18,18; MaCt 1 "t, 69; MgCtji 3.80; 63.33; The degree of yasya yoni for potassium chloride is 0.95. Coolant is carried out to obtain a stock solution having the composition,%: KCt 9.97; NeCl 16.17; MgCt, 18; 69.68; Step on sodium chloride 0.87. Guidelines are classified according to the class 0.3 mm, air classification - according to the class t 0.3 mm. The water that is injected into the first Crystallization process in the form of hot water and

steam, divided into two streams in the ratio of 1: 4, a smaller part is introduced directly into the hot clarified solution after dissolution, a large amount is fed to the processing of dust fractions

and crystalline potassium chloride.

The distribution of streams, as well as the content of the components in them, is given in the table. ;;;;

Claims (1)

Claim A method for producing dustless potash fertilizers by processing sylvinite ores by dissolving followed by separation of potassium chloride from the resulting solution by a multi-stage vacuum vacuum crystallization and returning the ore from fractions to the beginning of the process, characterized in that, in order to enlarge the crystals of the Commodity Product and utilize dust fractions, crystallization is carried out to obtain a suspension with a degree of saturation of the solution with sodium chloride of 0.97-0.98, followed by classification of the solid phase into coarse-grained and fine-grained allichesky products, their isolation from the suspension, washing the coarse product, drying, dust removal, water treatment dust fraction and voz40 gates together with the washings from the coarse fraction in the crystallization process by treating fine-grained product with water and steamed to produce a slurry temperature of 45 -100 ⁰ L ^with C and feeding the latter into the solution before vacuum crystallization.