Press-granulating process of non-ductile salts

a press-granulating and non-ductile salt technology, applied in the field of press-granulating non-ductile salts and salt mixtures, can solve the problems of inability to press hard salts, inability to work with salts which are difficult to press, and need an additional thermal drying treatment for rolling granulates, etc., to achieve high efficiency and cost-effective

Inactive Publication Date: 2017-05-11
KAPS STEPHAN +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This present invention is a process for making granulate with desired grain size. The process involves mixing salt and additive, and then compacting them using press rollers at high pressures. The resulting product is stored without heating for a certain period of time to allow for curing. The process reduces the occurrence of fine dust and increases the yield of granulate with the desired size. Molasses is used as an effective and cost-efficient additive, which can be directly added to the salt or salt mixture in a mixer. The temperature of the mixture should not exceed 25°C after mixing. The technical effect of this process is to provide a simple and effective method for making granulate with desired grain size.

Problems solved by technology

Said process has been successfully used for chloride-containing salts, but does not work for salts which are difficult to press, especially sulfate-containing salts, since the compacting using a roller press requires a certain ductility and fluidity of the salts under high pressure, which is true for potassium chloride and sodium chloride, but not for the mentioned potassium-, magnesium- and calcium containing sulfate minerals.
Furthermore, roll granulates require an additional thermal drying treatment.

Method used

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  • Press-granulating process of non-ductile salts
  • Press-granulating process of non-ductile salts
  • Press-granulating process of non-ductile salts

Examples

Experimental program
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example 1 (see fig.1)

Example 1 (SEE FIG. 1)

[0015]5 tons of a mixture of 70 parts kieserite, 22 parts langbeinite, 6 parts anhydride and 2 parts clay minerals with a grain size of 95%1) until a homogenous distribution is obtained. Occasionally, agglomerates up to 5 mm are formed. The temperature of the mixture shall be 2) with fine grains from the product sieving which is fed back into the process, and is fed back into the pressing cycle. The material which has been pre-compressed in a stuffing screw (3) is fed into the roller press (4) with counter-rotating compacting rollers, and is compacted using pressures from 200 to 250 bar. An about 7 to 20 mm strong foil is obtained, which is continually formed next to small parts of non-pressed fine salt. Since the press scrubs are initially very soft, the mixture of scrubs and fine grains is pre-crushed using a spiked roller (5) into parts being at maximum 10×10 cm of size, stored in a Silo (6) for at least 3 to 4 hours, and afterwards the cured mixture is siev...

example 2 (see fig.2)

Example 2 (SEE FIG. 2)

[0018]20 tons of polyhalide (K2504.MgSO4.2CaSO4.2H2O) from a natural resource is mixed with an additive of 4 to 4.6% by mass of sugar beet molasses and a total sugar amount of 47% in the dry matter. The mixture of the finely grained mineral salt with a grain size of 0 to 2 mm and the molasses occurs at environmental temperature in a continuously working mixer (1) in throughput. To said continuously working mixer (1), the sieved fine grain from the granulate sieving is added. Said mixture is fed to the press rollers of the roller press (3) via a stuffing screw (2), wherein press pressures up to 280 bar result at first in soft scraps, which, after pre-crushing in a spiked roller (4) is obtained in form of palm-sized parts. Said mixture, after passing a charging sieve (5) is separated into two streams. The screen underflow, which consists of non-pressed material and smaller scrap parts, is transferred into a separate maturing silo (6), the large scraps are transfe...

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Abstract

Process of press-granulating non-ductile salts and salt mixtures, such as kieserite (MgSO4.H2O), langbeinite (K2SO4.2MgSO4), polyhalide (K2SO4.MgSO42CaSO4.2H2O), arcanite (K2SO4) and anhydrite (CaSO4) for preparing stable, storable granulate, by pressing a mixture of fine grains of salt and a viscous, sugar-containing additive, such as molasses having a total sugar content in the dry matter of from 47 to 55%, by roller pressing at pressures up to 260 bar. The press scraps initially obtained, which are ductile, are solidified by maturing of the material at temperatures between 20 and 40° C. and maturing times of 3 to 8 hours prior to crushing them in impact mills and sieving.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a divisional of prior U.S. application Ser. No. 14 / 208 475, filed March 13, 2014, which claims priority from German Application No. 102013004597.5, filed Mar. 15, 2013.FIELD OF THE INVENTION[0002]The invention relates to a process of press-granulating non-ductile salts and salt mixtures, especially sulfate-type mineral salts, such as kieserite (MgSO4.H2O), langbeinite (K2SO4.2MgSO4), polyhalite (K2SO4.MgSO4.2CaSO4.2H2O) or arcanite (K2SO4) or mixtures of these salts. These compounds represent valuable potassium-sulfur or potassium-magnesium-sulfur fertilizers being free of chloride, which can be gained via mining or from crystallized potassium containing raw salts of polymineralic compositions, and which can be used as polynutrient fertilizers following respective granulation via press-pelletizing. Said fertilizers gain more and more interest since they are free of chloride, and thus counteract the ground salinization in arid clim...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C05G3/00B01J2/22C05D1/00B02C23/12C05D1/04
CPCC05G3/0058B02C23/12B01J2/22C05D1/005C05D1/04C05G5/12
Inventor KAPS, STEPHANSCHERZBERG, HEINZHEUCHEL, BARBARA
Owner KAPS STEPHAN
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