Method for preparation of moisture resistant potassium chloride with enhanced rheological properties

FIELD: chemistry.

SUBSTANCE: invention refers to the method for preparation of moisture resistant potassium chloride with enhanced rheological properties. The method includes compression of the concentrated potassium chloride obtained by the halurgic or flotation concentration of the sylvinite ore with the additive of the mineral substance. The aforesaid mineral substance is structure-forming salt selected from the potassium or sodium carbonate, sulphate, dihydroorthophosphate, orthophosphate or metasilicate, it is fed to the wet concentrate in the stage of structural agglomeration before drying. The latter stage is carried out at moisture level 3.0 - 5.0% in turbo-bladed mixer-granulator by the way of plastic deformation of the wet concentrate mixed with dry hot potassium chloride. The structure-forming salt is fed in amounts of 0.5 - 5.0 kg/t of the ready product (dry or in the form of water solution). The dry hot potassium chloride is fed to the stage of plastic deformation in amounts of 10 - 20% in relation to the weight of the dry agglomerated potassium chloride.

EFFECT: method is versatile and allows to obtain the fine and compression granulated potassium chloride which is able without treatment with anti-clodding agent to retain its grain size composition and flowability at storage and handling in wet climate.

4 cl, 4 tbl, 1 ex

 

The invention relates to a technology for moisture potassium chloride with improved rheological properties in the form of small (fine) and granulated by pressing fertilizer from sylvinite ore gallerycheck and flotation methods of enrichment. Fertilizer potash products, as the dispersed material is moisture-proof, if it has the ability to maintain flowability, not leivas, and granulometric composition, not being under the influence of moisture and the ambient temperature during storage and transportation.

Know the use of various mineral salts in the process of obtaining granulated by pressing flotation of KCl to increase the resistance of the granules to the destruction during storage and transportation in humid climates [Patent No. 2083536 (RF) / skvirsky L.Y., Goat SL and other Method for granulated potassium chloride, Byull. inventions 1995, No. 19; Slopel, Medresesi, Nagoya, Snigireva. Physico-mechanical properties of granulated potassium chloride. In Proc. of the scientific. proceedings of the JSC "all-Russian research Institute of Mineral" / edited Uwisuki "Topical issues of extraction and processing of natural salts". SPb.: Niizk St. Petersburg state University, 2006. - 181-191 C.]. As mineral salts is proposed to use soda ash (Na2CO3), one-deputizing the ammonium phosphate (map) - NH H2PO4and metasilicate sodium (Na2SiO3). Mineral salt, taken in an amount of 0.5-2.0 kg per ton of granules, serves in the process of obtaining pellets before drying wet flotation concentrate.

The disadvantage of this method is that, despite the use of mineral salts applied before drying in wet flotation concentrate KCl, and also on the stage of finishing granulate standard fraction (-4)-(+2 mm), unable to get water-resistant finished products without additional processing of granular KCl-caking agent is an amine at a flow rate of 120 g per tonne. According to the presented in this work data it is impossible to provide moisture-resistant granular KCl only due to the binding effect of chemical interaction of mineral salt KCl flotation concentrate. Specified chemical interaction leads to a substantial reduction in the hygroscopicity of the granules, but does not lead to the desired compaction of dispersed material in the baling process.

A method of obtaining agglomerated KCl [RF Patent №2213078, 29.08.2001 - 27.09.2003, JSC "Silvinit", buksa J.V. and others, C01D 3/04, C05D 1/02 "Method of obtaining agglomerated potassium chloride"; Herzberg SCI, Deryabin P.A. Agglomeration as a way to improve physical and mechanical properties of potassium chloride". Sat. the scientific. articles of JSC "all-Russian research Institute of Mineral". Actual the issues of extraction and processing of natural salts, volume 2: Processing of natural salts, Ed. Uwisuki. - SPb.: Information and publishing Agency "FACE", 2001, p.70-75]. The method of obtaining agglomerated potassium chloride from fine potassium chloride fraction (-0,25 mm) includes the introduction of wet concentrate reagent that promotes agglomeration, mixing the mixture and dried in the drying apparatus, characterized in that as the wet concentrate use potassium chloride formed during the processing of sylvinite ore in a wet concentrate is injected cyclone dust captured at the stage of dry flue gas drying apparatus, before drying, the mixture is passed through TurboPascal mixer-granulator for homogenization of the charge on the granulometric composition, humidity, mechanical activation of the particles of potassium chloride to obtain granules, the latter served in vibropitateli for sealing and okutyvaya. As agglomerated reagent injected inorganic substance that reacts with potassium chloride with the formation of double salts having a lower hygroscopicity than potash.

The disadvantages of this patent. Unfortunately, the patent does not specify granulometric composition of the finished product and are not given with respect to its mechanical properties. The mechanical properties of the dispersed products include flowability, angle of repose, grated is here, flaking. Hygroscopicity is the physico-chemical characteristics, especially in the patent is only moisture absorption. As is known [Kuvshinnikov IM fertilizers and salts: Properties and ways to improve them. - M.: Chemistry, 1987, s, 164], the hygroscopic fertilizer method Pestova speed of moisture absorption allows to obtain only qualitative, approximate characterization of the samples. In turn, the caking of the dispersed water-soluble material is not a function of hygroscopicity or Vice versa. Also known fact [ibid, s]that the formation of double salts or solid solutions on the surface of grains dispersed material leads to a sharp decline in its hygroscopicity. According to [Topical issues of extraction and processing of natural salts. Sat. the scientific. proceedings of the JSC "all-Russian research Institute of Mineral" / edited Uwisuki. SPb.: Niizk St. Petersburg state University, 2006. 192 S.] the resistance of the granules KCl is the main criterion for the safety of their consumer properties. Under moisture understand the ability of water-soluble dispersed material to maintain the mechanical properties after moistening of the material, not its moisture absorption. That is shown in patent values of moisture absorption of the obtained sintered product to judge its moisture resistance is impossible.

In addition, the patent notes, in the process of drying the agglomerated product is the crystallization of the impregnating solution between particles. This statement suggests that agglomeration in TurboPascal the mixer is carried out on a capillary mechanism, which is provided by the humidity glomerulosa material of more than 5%. According to the description of this patent as the source material is only used fine wet concentrate fraction (-0,25 mm), which is produced, for example, as a result of hydroclassification total product of the flotation. The strength of the granules obtained in this sintering process, depends, as is well known [Posin ON the Technology of mineral fertilizers. L.: Chemistry, 1989, p.62], size of the granulated particles. The smaller particles of the granulated powder, the stronger granules. Therefore, this method is not applicable for General product flotation with particle size (-2 mm). Along with this, the obtained sintered product according to example description contains 0.5% of water that does not meet the requirements of standard potassium chloride HUNDRED SPECS 001-98.

Known technology and equipment for complete installation of pelletized by pressing and fine dust-free flotation of KCl developed for reconstruction of the 3 RU OJSC "Silvinit" [Sabirov P.P., Ceballo VA, Vinnikov NM "Development of technology and equipment is the equipment of complete installation of pelletized KCl compaction method. - Sat. scient. proceedings of the JSC "all-Russian research Institute of Mineral" / Actual problems of extraction and processing of natural salts. Ed. Uwisuki - SPb.: Niizk St. Petersburg state University, 2006, s-203]. Developed hardware and technological scheme is as follows. The original wet flotation concentrate together with cyclone dust drying apparatus and pneumological served for agglomeration in TurboPascal mixer, where does the solution of the binder. Wet agglomerated mixture is supplied to the drying furnace with a fluidized bed. The hot dry flotation concentrate granularit pressing. Granulate with a particle size of 2-4 mm) is fed to the installation of refining and chemical treatment of the caking agent and paletteviewer.

The disadvantage of this technology is that it is designed only for small and granulated by pressing KCl in the process of flotation of sylvinite ore. In addition, in the present material there is no information about the composition of the binder used in the process of sintering and technological parameters of this process in TurboPascal mixer.

The closest in technical essence and the achieved result of the present invention may include a method of obtaining potassium fertilizers in the form of granulates, which even at high relative authorities the particular air stable during storage [RF Patent №2181112(13)C2; 7 C05D 1/00, B01J 2/22; 2002.04.10 - 2000.04.27; DE; KALI UND SALZ, GMBH (DE); a Method of producing fertilizer in the form of compressed pellets]. This invention relates to the production of potassium chloride in the form of granules by compacting the dry fine product from the process of dissolution or flotation of potash ore. The problem of obtaining water-resistant extruded granules of potassium chloride by the authors of the patent is solved by pressing the dry fine potassium salts, in which before the pressing process uniform dosing add dry magnesium oxide and/or calcium oxide to obtain a homogeneous mixture.

According to this technology, the proportion of the additive of magnesium oxide and/or calcium in the dry granulate is 0.2 to 2.0%, preferably 1.0 to 1.5%. As the oxide supplements offered the use of quicklime or burnt dolomite.

The disadvantage of the prototype is the need to introduce in the compression fine KCl relatively large number of oxide supplements of magnesium and/or calcium to its content in the finished granulate 1.0 to 1.5%, which complicates the process of flotation or galilejskogo enrichment of sylvinite ore. In addition, there is no information about the resistance of fine KCl with these additives, which in the absence of sales granules is often inevitable and economically suitable the M.

Before the invention tasked with securing the moisture of potassium chloride with improved rheological properties of both small and granulated by extrusion in the process galilejskogo and flotation of sylvinite ore. When this moisture produced any brand KCl is characterized by the ability of the dispersed material to maintain the flowability and the granular composition during storage and transportation in wet climate without treatment-caking agent-amine.

It was established experimentally that the resistance KCl fertilizer depends on and is determined by the structural-mechanical properties of its constituent grains, agglomerates, granules, that is, the degree of perfection of their structural characteristics. Therefore, to obtain moisture dispersed material you want to affect the original structure of the particles. To improve the structure of water-soluble crystalline dispersed material in the process of agglomeration. Since KCl is maloplastichnye material, getting it agglomerates and granules with dense and durable structure similar to that of single crystals of this salt, is possible only as a result of significant external mechanical impact on the source of fine material. This mechanical action is provided by the CE structural agglomeration of fine KCl in a special mixer-granulators, for example in the mixer-granulator of Ariha [Aufbereitungstechnik, 44 (2003), №2], and in the process of pressing. Because the process of agglomeration of particles is a complex physico-chemical process of recrystallization, in the development of this method took into account its dislocation mechanism. Dislocation mechanism of recrystallization process is provided according to the proposed method used in the sintering process of mineral salt structure, which provokes the formation of dislocations in crystals of KCl. The choice of structure-forming salt is defined as the volume (size) of ions of salt and mineral supplements, and its chemical interaction with KCl and/or impurities contained in concentrate.

Tasked with securing the moisture of potassium chloride with improved rheological properties, both small and granulated by extrusion, is solved by structural agglomeration, which is carried out before drying wet concentrate from the process galilejskogo or flotation of sylvinite ore. Structural agglomeration of the total mass of the wet concentrate KCl is carried out by plastic deformation in the presence of mineral structure-forming salt and dry hot concentrated potassium chloride. As structure-forming salts are encouraged to use the carbonate, sulfate, dig groothoff, the orthophosphate, metasilicate potassium or sodium. Structure-forming salt is fed into the process in a dry form or in aqueous solution in the amount of 0.5 to 5.0 kg of mineral salts per tonne of finished product. This consumption of salt corresponds to the proportion of its content in the finished product, 0.05 to 0.5%. The hot dry concentrate, potassium chloride, presents cyclone dust drying apparatus and/or a part of their discharge, taken in an amount of 10-20 % by weight of dry agglomerated KCl, serves to plastic deformation of the original wet concentrate of potassium chloride at the stage of structural agglomeration. Structural agglomeration is carried out in TurboPascal mixer-granulator at a moisture content of material, equal to 3,0-5,0%.

Obtained in the process of structural agglomeration wet agglomerated concentrate KCl, in which the particle fraction -0,1 mm was enlarged to fraction +0.1 mm, dried in a drying apparatus of any design. Upon receipt of the finished product in the form of small KCl drying the agglomerated wet concentrate is carried out at a material temperature of 70-100°C. the Obtained fine agglomerated KCl contains almost no faction -0,1 mm

Upon receipt of granulated by pressing KCl drying combined with heating of the material for pressing and carried out at a temperature required for extrusion. The finished small alomari is consistent and/or granulated by extrusion of potassium chloride is not treated with caking agent is an amine. The choice of structure-forming salt of a number of proposed mainly determined by technical and economic conditions of production KCl, as well as price and availability.

The main positive effect of the present invention is its universality and complexity in solving the problem of production of water-resistant fine and granulated by pressing galilejskogo and flotation of potassium chloride, capable of without treatment-caking agent-Amin save granulometric composition and flowability during storage and transportation in a humid climate. In addition, the proposed solution improves the performance of the drying equipment and reduces fuel consumption due to speed up the process of dehydration of the wet material with a dense structure. This invention is illustrated below in the following examples of its implementation.

Example

Wet concentrate of potassium chloride with centrifuges or filters from the process galilejskogo or flotation of sylvinite ore is treated in TurboPascal mixer-granulator (GCL has). There also is served hot dry small KCl in the amount of 15% by weight of the discharge of the drying apparatus and fine dry soda ash or other structure-forming reagent, taken in an amount of 1.0 kg per ton of dry agglomerated product.

Receiving the hydrated agglomerated wet concentrate is dried in the drying apparatus when the material temperature is not higher than 100°C. Part of the discharge of the drying apparatus - ready small product analyzed for particle size distribution, moisture content, angle of repose, the flowability (flow) on the expiration time from the hopper, abrasion class (-0,2 mm) upon receipt and after storing it in a climate Cabinet (CS) at a temperature of 20°C, relative humidity 80,0% within one day (24 hours).

The flowability of the obtained agglomerated KCl assessed by the speed of the expiration of the dispersed material of a glass funnel. The method of its determination is to measure the time of expiration of a certain mass of the specimen (150 g) of the funnel with the angle of inclination of the generatrix 45 deg. and the diameter of the outlet 20 mm.

The moisture resistance of the obtained agglomerated samples KCl appreciate the change in the flow properties and the abrasion of small KCl before and after moistening them when stored in a climatic Cabinet. For moisture dispersed material relative change of these parameters practically do not exceed 5.0 percent.

Part of the discharge of the drying unit served in the GCL has on the handling of wet concentrate. The remaining agglomerated potassium chloride is heated to 120-130°C and granularit pressing. Obtained after crushing and classifying granular standard size (2-4 mm) are tested for abrasion class (-2,0 mm)and impact strength before and after hydrate pellets in a climatic Cabinet at 20°C and relative humidity of 80% for one day.

For experiments on a pilot plant with centrifuges taken moist concentrate galilejskogo (method of dissolution and crystallization) production of potassium chloride, which consists of polycrystalline grains obtained under conditions of unregulated vacuum crystallization (ICD), as well as polydisperse wet concentrate flotation of sylvinite ore. Table 1 shows the particle size distribution of the original wet particulate materials used in the experimental trials. Table 2 shows their chemical composition in terms of dry substance.

Table 1
Granulometric composition of the original wet concentrate, potassium chloride
Material nameThe granulometric composition of the material, particle size, mm content, mass. %
0,80,50,250,1-0,1
1. Wet concentrate galilejskogo production KCl scheme with internals--23,563,912,6
2. Wet flotation concentrate production KCl2,26,830,337,723,0

Table 2
The chemical composition of the original galilejskogo and flotation concentrates KCl in terms of dry substance
Material nameThe content of the component masses. %
KClNaClMgCl2CaCl2CaSO4The insoluble residue
1. Wet concentrate galilejskogo production KCl scheme with internals96,433,230,180,130,03-
2. Wet flotation concentrate production KCl96,112,820,090,080,12 0,78

We have investigated the chemical interaction of mineral salts Na2CO3, NaH2PO4, Na2SiO3, Na2SO4used as a structure-forming reagent at the stage of structural agglomeration, potassium chloride and contained in concentrate impurities salts of magnesium and calcium. Using x-ray diffractometer DRON-6 and chemical analysis revealed that when using soda almost half contained calcium ion, and the small amount of magnesium ions bound to carbonates and basic salt of magnesium. When used as a reagent sodium metasilicate main part of magnesium ions bound in the form of amorphous compounds.

When using one-deputizing phosphate, the formation of double phosphate salt with potassium chloride and soluble calcium phosphate.

When using sodium sulfate or potassium form a double sulfate salt of potassium and sodium with calcium chloride - soluble calcium sulfate. For basic control of potassium chloride is taken small product obtained after drying, the source of the wet concentrate galilejskogo and flotation of sylvinite ore, and the granulate from it.

Wet concentrate galilejskogo production internals dehydrated in the drying apparatus when the temperature of the material is not less than 130°C, since at lower temperatures the complex polycrystalline structure of grains with occluded particles inside the fallopian solution to dehydrate to a moisture content of not more than 0.2% is not possible.

Wet flotation concentrate production is dried under conditions identical to the drying of wet agglomerated material, i.e. material with the temperature not higher than 100°C, according to the present invention.

In tables 3 and 4 shows the results of implementation of the invention for small agglomerated and granulated by extrusion of potassium chloride from galilejskogo and KCl flotation concentrate.

Are shown in tables 3 and 4 the results indicate the possibility of obtaining water-resistant potash products, small and granulated by extrusion without additional processing by-caking agent is an amine, according to the technology of the present invention.

The practical implementation of the present invention are possible in enterprises producing potassium chloride gallerycheck and flotation methods enrichment of sylvinite ore.

1. The way to obtain moisture potassium chloride with improved rheological properties by pressing concentrate potassium chloride galilejskogo or flotation is concentrating sylvinite ore with the addition of mineral substances, characterized in that the mineral substances using structure-forming salt is selected from a carbonate, sulfate, dihydroorotate, orthophosphate, metasilicate potassium or sodium, which are served before drying in the wet concentrate on structural stage agglomeration and structural agglomeration is carried out at a moisture content of 3.0-5.0 percent in TurboPascal mixer-granulator by plastic deformation of the wet concentrate is mixed with dry hot potassium chloride.

2. The method according to claim 1, characterized in that the structure-forming salt serves in the amount of 0.5 to 5.0 kg per tonne of finished product in dry form or in aqueous solution.

3. The method according to claim 1, characterized in that the plastic deformation of the hot dry potassium chloride serves in the amount of 10-20% by weight of dry agglomerated potassium chloride.

4. The method according to any one of claims 1 to 3, characterized in that the structural agglomeration along with water-resistant granular pressing the product obtained is water-resistant fine agglomerated potassium chloride.



 

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