DE2224181A1 - Pk fertilizer granulation - with improved throughput - Google Patents

Abstract

In a process for granulating PK fertilisers by continuously mixing Thomas phosphate and potassium fertiliser salt with water or salt solns. granulating in a screw granulator and a drum granulator, drying, sieving and recycling the undersize and comminuted oversize material, throughput and yield are improved by effecting one or more of the following modifications in the first stage (mixing of the Thomas phosphate, potassium salt and water or salt soln). (a) addn of phosphoric acid in an amt corresponding to the amt of CaO in the Thomas phosphate; (b) using soft earthy raw phosphate instead of at least part of the Thomas phosphate; (c) using calcined phosphate instead of at least part of the Thomas phosphate; (d) using MgSO4-contg. cpds. (pref. kieserite) instead of all or part of the potassium salt; and (e) adding N-contg. cpds. (pref. urea).

Description

"Process to increase throughput capacity and yield the granulation of a PK fertilizer "To the not previously published status of Technology is part of a process to increase throughput capacity and yield when granulating a PK fertilizer based on Thomas phosphate and potash fertilizer salt ", which is characterized by the following process steps: 1) continuous mixing of Thomas phosphate with practically dry potash fertilizer salt with about 50 - 60 ffi IC2O, 2) pre-moistening of the mixed material from stage 1 to about 2 wt .-% water the mixture calculated, 3) pre-moistening of the return material from level 9 to about 2 - 5% by weight of water, calculated on the mixture, 4) introduction of the pre-moistened Substances from stages 2 and 3 in the screw granulator and residual moistening about 9-13% by weight of total water, calculated on the mixture, 5) entry of the pregranulated Mixture from level 4 into the granulating drum with an inclination of over 10 ° to 240 ° the horizontal with a speed of rotation of over 8 - 15 min-1, 6) drying of the moist granulate at an outlet temperature of approx. 110 - 14o0C, 7) sieving of the hot oversized grain, comminution and return to the sieving, 8) separation of the granulate and cooling to 30 - 60 ° C, 9) return of the return material for pre-moistening in stage 3.

As an extension of this procedure according to DBP ... (patent application P 22 05 082.4) to increase the throughput capacity and yield during granulation a PK fertilizer based on Thomas phosphate and potash fertilizer salt by continuous Mixing of the starting materials with the addition of water or salt solutions for adjustment the granulation moisture through built-up granulation in the granulating screw and drum, Drying, sieving, to separate the finished granulate, return of the undersized grain and the comminuted oversize, with the following process steps: 1) continuous Mixing the Thomas phosphate with practically dry potash fertilizer salt with approx 50 - 60% K2O, 2) pre-moistening of the mix from level 1 to approx. 2 - 5% by weight Water, calculated on the mixture, 3) Pre-humidification of the return material from stage 9 to about 2 - 5% by weight of water, calculated on the mixture, *) Introduction of the pre-moistened Substances from stages 2 and 3 in the screw granulator and residual moistening approx. 9 - 13 percent by weight of total water, calculated on the mixture, 5) entry of the pregranulated Mixture from level 4 in the granulating drum with over 100 to 240 inclination against the horizontal with a speed of rotation of more than 8 - 15 min 6) Drying of the moist granulate at an outlet temperature of approx. 110 - 1400C, 7) sieving of the hot oversized grain, comminution and return to the sieving, 8) separation of the granulate and cooling to 30 - 6o0c, 9) Return of the return material for pre-moistening In stage 3, a process was now introduced to increase throughput capacity and yield found in the granulation of a PK fertilizer, which is characterized is that in stage 1 optionally or together 1. phosphoric acid in an amount that corresponds to the CaO content of the Thomas phosphate and makes it practically insoluble in water P205 connection sets, is added, 2. soft-earthed rock phosphate in whole or in part instead of Thomas phosphate is used, 3. calcined phosphate in whole or in part instead Thomas phosphate is used, 4. Compounds containing MgSO4, preferably kieserite, be used entirely or partially instead of potash salts and 5. if appropriate N-containing component, preferably urea, can be added.

The method of the invention is illustrated by the following examples: Example 1 20 t of moist potassium chloride (55% K20 and 9% water) is mixed with 32 t of soft earth Rock phosphate (finer than 1 mm grain size and with a total P2O5 content of 31.6 %) and 40 t returned goods (cooled to 60 ° C and moistened to around 5%) and 8.5 m3 Granulating water mixed. The raw material mixture has an adhering content Water of 12.3%.

The moist granulate is placed in a roller drum (6 m long and 2.20 m Diameter) made with a slope of about 200 and in a rotating drum (24 m long) dried to a residual moisture content of around 0.8%. It fall about 90 tons of dry material, of which the oversized grain is ground and together with the rest Amount is sifted. The fine granulate of around 40 t is used in the granulation process returned. The granulate yield is about 55 to 56%.

The finished granulate has the following composition: 20 ffi total P2O5 and 20% K20 and the following grain composition:> 4.0 mm> 3.0 mm> 2.0 mm, 1.0 mm> 0.5 mm <0.5 mm 5.2% 14.5 ffi 29.9% 38.4% 10.8% 1.2% Example 2 Implementation according to example 1.

The raw materials and the product have the following composition: 13 t moist potassium chloride (55 ffi K20 and 9% water) 7 t rock phosphate (31.6% P2O5 31 t Thomas flour (19.4% P2O5) 40 t return material (5 ffi water) 9.0 m3 granulating water Die total adhering moisture of the raw material is 12.2%. 89.5 t of dry material fall of which 50.0 t are obtained as granules. The granulate yield is about 56%. Composition of the granulate: 15% P2O5 and 15 ffi K20.

Grain composition:> 4.0 mm> 3.0 mm> 2.0 mm> 1.0 mm > 0.5 mm <0.5 mm 2.9% 11.3% 26.9% 42.1% 14.5% 2.3% Example 3 Implementation according to example 1.

The raw materials and the product have the following composition: 16.3 t moist potassium chloride (55% K20 and 9% water) 8.5 t kieserite (27% MgO) 22.8 t Thomas flour (18 ffi P205, soluble in 2% citric acid, and 1.0% MgO) 4.0 t phosphoric acid (52% P205) 58.0 t returned goods (5 ffi water) 9.5 m³ Granulating water The total adhering moisture of the raw material is 12.6%. It fall 105.0 t of dry material, of which 50.0 t are obtained as granules. The granulate yield is approximately 47 to 48%.

Composition of the granulate: 12% P205, soluble in 2-citric acid, 18% K20 and 5% MgO grain composition:> 4.0 mm> 3.0 mm> 2.0 mm> 1.0 mm> 0.5 mm <0.5 mm 5.9 ß 12.8. 32.4% 36.0% 11.4% 1.5% Example 4 Procedure according to example 1.

The raw materials and the product have the following composition: 16.3 t moist potassium chloride (55% K20 and 9% water) 9.0 t kieserite (27% MgO) 26.5 t calcined phosphate (29.2% P2O5, soluble in 2% citric acid, and 0.5% MgO) 40 t returned goods.

8.5 m3 of granulating water The total amount of adhering moisture in the raw material is 11.8%. 89.5 t of dry material are obtained, of which 48.5 t are obtained as granules will. The granulate yield is approximately 54 to 55%. Composition of the granulate: 15% P205, soluble in 2% citric acid, 18% K20 and 5% MgO grain composition: > 4.0 mm> 3.0 mm> 2.0 mm> 1.0 mm> 0.5 mm <0.5 mm 5.4% 14.0% 31.1 ffi 35.6 ffi 12.2%% 1.7% Example 5 Implementation according to Example 1.

The raw materials and the product have the following composition: 42 t Thomas flour (18, soluble in 2% citric acid, and 1 ffi MgO) 8 t kieserite (27% MgO, finer than 1 mm grain size) 50 t return material 10.0 m3 granulating water The entire adhering moisture of the raw material is 12.1%. There are 99 t of dry material, of which 50 t can be obtained as granules. The granule yield is about 50 to 51%.

Composition of the granulate: 15 ß P205, soluble in 2% citric acid, 5% MgO grain composition:> 4.0 mm> 3.0 mm> 2.0 mm> 1.0 mm> 0.5 mm <0.5 mm 3.1% 11.8% 31.2% 40.5 ffi 11.5 ffi 1.9% Example 6 Implementation according to example 1.

The raw materials and the product have the following composition: 2 #, 8 t Thomas flour (18% P205, soluble in 2% citric acid) 9.7 t urea (46.5 % N) 13.6 t potassium chloride (55 ffi K20 and 9 ffi water) 40.5 t return material 8.4 m3 granulating water The total adhering moisture of the raw material is 11.7%. 89.0 t of dry material fall of which 48.0 t are obtained as granules. The granulate yield is approx 54%.

Composition of the granulate: 9% N, 10% P205, soluble in 2% strength Citric acid, and 15 ffi K20.

Grain composition: 4.0 mm> 3.0 mm> 2.0 mm> 1.0 mm> 0.5 mm <0.5 mm 4.3% 13.5% 28.9% 38.7% 12.8% 1.8% Through the Whole or partial replacement of Thomas phosphate or other P205 components with water-insoluble P205 in level 1 as well as through the use of MgS04-hiltigen Compounds in whole or in part instead of potash salts in stage 1 as well as through the addition of N-containing components, preferably urea, is the method of the parent patent (patent application P 2205 082) for granulating a PK fertilizer advantageous to the production of other granulated PK fertilizers or PMg fertilizers or NPK fertilizers or NPKMg fertilizers expanded.

The method of the invention thus offers the possibility of this technical Granulation process of the parent patent also applies to other nutrient components that are entirely or partially replace Thomas phosphate or potash fertilizer salt in stage 1, expand.

Claims (4)

Patent claims 1. Method of increasing the throughput capacity and yield of a Fertilizer as a further development of the method according to DBP ... (patent application P 22 05 082.4) to increase the throughput capacity and yield during granulation of a PK fertilizer based on Thomas phosphate and potash fertilizer salt through continuous Mixing of the starting materials with the addition of water or salt solutions for adjustment the granulation moisture through built-up granulation in the granulating screw and drum, Drying, sieving, to separate the finished granulate, return of the undersized grain and the crushed oversized grain, with the following process steps: 1) continuous Mixing the Thomas phosphate with practically dry potash fertilizer salt with approx 5o - 60% K20, 2) Pre-moisten the mix from level 1 to about 2 - 5 wt. Water, calculated on the mixture, 3) Pre-moistening of the return material from stage 9 to about 2 - 5% by weight of water, calculated on the mixture, 4) introduction of the pre-moistened Substances from stages 2 and 3 in the screw granulator and residual moistening approx. 9 - 13 wt. total water, calculated on the mixture, 5) entry of the pregranulated Mixture from level 4 in the granulating drum with over 100 to 240 inclination against the horizontal with a speed of rotation of over 8-15 min 1, 6) drying of the moist granulate at an outlet temperature of approx. 110 - 1400C, 7) sieving of the hot oversized grain, size reduction and return to the sieving, 8th) Separation of the granulate and cooling to 3o - 6o0C, 9) return of the return material for pre-moistening in level 3 ,. characterized in that in stage 1 either or together 1. Phosphoric acid in an amount that corresponds to the CaO content of the Thomas phosphate and this binds to practically water-insoluble P205 compound, is added, 2. Soft-earthed rock phosphate used entirely or partially instead of Thomas phosphate will, 3. Calcined phosphate wholly or partially used instead of Thomas phosphate will, 4. Compounds containing MgSO4, preferably kieserite, in whole or in part be used instead of potassium salts and 5. if necessary N-containing component, preferably urea can be added.