Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
• • C—CHEMISTRY; METALLURGY
  • C05—FERTILISERS; MANUFACTURE THEREOF
  • C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
  • C05G5/00—Fertilisers characterised by their form
  • C05G5/10—Solid or semi-solid fertilisers, e.g. powders
  • C05G5/12—Granules or flakes

Definitions

• the invention relates to the industry of mineral fertilizers and can be used in production of dry compound fertilizers (NPK), which involves use of urea.
• NPK dry compound fertilizers
• the invention further relates to use of hardening slurry for production of fertilizers and preparation of fertilizers having high total nitrogen concentration.
• Urea is a concentrated nitrogen fertilizer with 46% of nitrogen, which can be used directly as a single nitrogen fertilizer or as a raw material for production of nitrogen, phosphorus and potassium (NPK) compound fertilizers.
• a disadvantage of urea is that in water solutions (acid ones in particular) at relatively low temperatures (exceeding 50-60 o C) it undergoes hydrolysis and disintegrates into primary components: ammonia and carbon dioxide. This leads to nitrogen loss, environmental pollution, and necessity of additional equipment for cleaning of emissions.
• the closest prior art is the European patent EP1127035 with priority date of 29 June 1998 and published on 6 January 2000 that describes a method for production of granulated compound fertilizer that consists of at least two basic nutrients: nitrogen, phosphorus and potassium.
• the patent describes a method for the preparation of compound fertilizer granules by mixing solid raw materials with fine recycle material, melting a part of solid raw materials in a melter, mixing with remaining part of solid raw materials, granulating, cooling, screening, and packing. Throughout the process the dry components are moistened neither with water, nor with steam, therefore fertilizers are not dried. The drying stage is eliminated and thus the technological process gets simplified.
• a disadvantage of this method is that energy consumption for melting some of the components (10-40%) is high: very hot air (200-550 o C) is supplied to the melter, moreover, components required for melting are additionally heated to reach the temperature of 80-110 o C.
• total nitrogen concentration in compound fertilizers is not high, for example, fertilizer grade is 18-12-6, 17-17-17, there are no fertilizers needed for springtime fertilization.
• the present invention is aimed to provide such a method for production of compound fertilizers that enables preparation of compound fertilizers with high nitrogen concentration in a simplified way, i.e., without a drying stage and with reduced energy consumption and atmospheric pollution.
• the method for production of dry compound fertilizers that is being patented comprises mixing of dry components in a mixer and granulating of them.
• up to 50 % of hardening slurry that supports the process of granulating can be fed into a mixer.
• the optimal quantity is chosen by considering the nature and physical-chemical properties of raw materials and the ratio of components.
• hardening slurry consisting of urea, sulphuric acid, magnesium and ammonium sulphate is additionally fed into the granulator wherein mass ratio of dry component and slurry is 1:0.1-0.6, preferably 1:0.2-0.5.
• Preparation of hardening slurry comprises following three stages:
• the magnesium component is melting product of periclase with MgO content of more than 75% and particle size of no more than 2 mm.
• the method for preparation of compound fertilizers being patented simplifies the process and reduces energy consumption and atmospheric pollution as fertilizer drying is no longer necessary.
• Fig. 1 shows a flow sheet of production of dry compound fertilizers.
• Dry compound fertilizers are produced as shown in the flow sheet (Fig. 1). Dry components for fertilizer production are fed from bunkers (1) onto weighing scales (2), weighed and fed by mechanical feeders (3,5) and elevator (4) to mixer (6) and then to granulator (11). Hardening slurry produced in reactor I (7) by mixing urea with diluted sulphuric acid is also fed into granulator. The obtained urea and sulphuric acid slurry is (in) mixed with magnesium component in reactor II (8), slurry production is finished in reactor III (9) by adding ammonium sulphate. The obtained urea, sulphuric acid, magnesium and ammonium sulphate slurry is fed by pump (10) into granulator (11).
• Granulated compound fertilizers are elevated by elevator (12) to sieve I (13) from which fine material is returned to mixer (6) and the remaining material is cooled in cooler (14), screened in sieve II (15), marketable part of the product is delivered to storage while the coarse material is crushed in crusher (16) and screened in sieve II (15).
• Standard fertilizer analysis methods are used to determine concentrations of nitrogen, phosphorus, potassium, magnesium, sulphur and other elements in as well as physical-chemical properties and marketability indicators of dry compound fertilizers.
• Compound fertilizers were produced in industrial-grade machine at output capacity of 10 tons per hour. Composition of dry substances and slurry used in production of dry compound fertilizers is illustrated by the following examples.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Pest Control & Pesticides (AREA)
• Fertilizers (AREA)

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• 2013
  • 2013-01-31 LT LT2013007A patent/LT5974B/lt not_active IP Right Cessation
  • 2013-03-25 WO PCT/IB2013/052345 patent/WO2014118600A1/en active Application Filing
  • 2013-03-25 EP EP13722082.8A patent/EP2951136A1/en not_active Withdrawn
  • 2013-03-25 EA EA201500269A patent/EA201500269A1/ru unknown

Non-Patent Citations (1)

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