DE2205082A1 - Granulating thomas phosphate potash fertilizers - with increased yield of useful size particles - Google Patents

Abstract

Process for increasing the yield and throughout in the granulation of PK fertilizers prepd. from Thomas phosphate (I) and K salt soln. comprising (I) with practically dry K salt contng. 50-60% K2O; (2) moistening prod. to 2-5 wt.% water; (3) moistening recycled material from stage 9 to 2-5 wt.% water; (4) discharging damp material to a worm granulator and adding more water to give 9-13 wt.% moisture; then (5) to a granulating drum of 10 degrees-24 degrees slope rotating at 8-15 rpm; (b) drying the damp granules at an exit temp. of 110-140 degrees C; (7) sieving the hot granules, removing over-sized particles, grinding and returning to sieve; (8) collecting the granules and cooling to 30-60 degrees C and (9) recycling residu to stage 3. Process gives high proportion of useful 1-4mm size particles and less material to be recycled.

Description

Process for increasing throughput capacity and yield the granulation of a PK fertilizer based on Thomas phosphate and potash fertilizer salt " The Auslegeschrift 1 417 932 relates to a method for the production of granulated Pli-fertilizers made from Thomas phosphate and potassium chloride. According to example 1, 666 Parts by weight (parts by weight) of Tnomas flour with 370 parts by weight of KCl with 24 parts by weight of water in a granulating device granulated and then dried in a rotary drum, the outlet temperature 132-1360c.

According to this process, the granulation should be carried out without recirculation of the returned material made from undersized grains and it should with a granulation moisture of only 2.3% Yield of 90 ffi granules with a grain size range of 1.5-3 mm can be obtained.

The reworking of this proposal showed that it was so small Moisture of the mixture to be granulated is not possible, such a granulate yield to obtain. It also means a technical step backwards when on tracing back of the undersized grain is dispensed with.

According to example 2 of this proposal, 700 GT of Thomas flour with 300 GT XCl and 50 GT water are mixed. The mixture should then be ground with 2100 GT Return material can be granulated with the addition of 170 GT of water.

According to this proposal, a mixture of Iooo GT starting materials should be used with 5% moisture with 2100 GT returned goods corresponding to 2oo% of the input goods Adding 170 parts by weight of water are granulated.

According to this proposal, a PK fertilizer with 12% P205 and 18% K20 can be produced with a yield of 90 ffi of the grain range from 1 - 3 mm, by circulating 2/3 of the total amount of solids and only about 1/3 is created as a product.

This considerable technical disadvantage of the load on the circuit by doubling the amount of circulating goods in relation to the input goods is based on the fact that only 220 parts by weight of water to a total weight of 322% by weight, corresponding to 6.65% total moisture, are used will.

The reworking of this proposal shows that it is not possible with a pre-moistening of the feed material to 5 ß water and a residual moistening the total mass including returned goods to 6.65% total moisture such A yield of granules of 1 - 3 mm can be obtained in a technical process.

The reworking of this proposal shows that the granulate yield not even if the moist mixture is stored for 1 to 48 hours can be reached. This intermediate storage also has the considerable technical Disadvantage that large storage capacities have to be created and a considerable one technical effort is required for the transport to the interim storage.

There has now been a method of increasing throughput capacity and Yield from the granulation of a PK fertilizer based on Thomas phosphate and potash fertilizer salt found, which avoids these technical disadvantages and a high granulate yield of 1 - 4 mm with only about 1/2 of the return material in relation to the Total amount of granulated material achieved.

The process of the invention operates with continuous mixing the starting materials with the addition of water or salt solutions to adjust the Granulation moisture through built-up granulation in the granulating screw and drum, Drying, sieving to separate the finished granulate, re-agitation of the undersized grain and the crushed oversized grain and is characterized by the following process stages: 1) 'continuous Mixing the Thomas phosphate with practically dry potash fertilizer salt with approx 5o - 60% K2O> 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 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 around llo - 14o0C, 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.

Furthermore, the method of the invention is characterized in that the amount of return material from level 9 is about 35 - 60 ß of the total amount of the pre-moistened Substances in level 4 is.

Modification of the method of the invention, characterized in that Chloride potash fertilizer salt with about 7-14%, preferably with 12% water the potash fertilizer salt is calculated, is used in level 1 and the pre-moistened substances be introduced in stage 4.

The device for performing the method of the invention is characterized in that the granulating drum has a ratio of diameter : Length of 1: 2.5-3, preferably with a length of 5-10 m.

The method of the invention is illustrated by the following examples and by the procedural scheme explained. The figures given apply to the same apparatus sizes.

Example 1 42 t / h of Thomas phosphate (16% P2O5) with 25 t / h chloride of potash fertilizer salt (54% K2O) in an intensive mixer (1) (Lödige company, Paderborn) mixed and with the addition of 2.8 tlh salt solution to a moisture brought the mixture of 4%.

In another intensive mixer (2) (Lödige, Paderborn) is the total return material of level 9 of 59 t / h with the addition of 2.45 tlh salt solution adjusted to a humidity of 4%. The pre-moistened substances are in a common bunker (3) is given, from where it is fed to two screw granulators (4) (Büttner-Schilde-Haas, Hersfeld). In these screw granulators they are mixed intensively and with the addition of another 10> 35 tlh salt solution, d. H. pre-granulated with a total moisture content of 11%.

The pre-granulated mixture becomes a granulating drum in free fall (5) abandoned. This is done with an incline of 200 to the horizontal and operated at a speed of 10 min -1.

The wet granulate is fed into a drying drum (6) in which it is gently dried. The dried goods leave the drying area with a Outlet temperature of about 1200 C.

The oversized grain is then screened off over 4 mm on a sieve (7), in a mill (8) ground and the comminuted material returned to the sieve (7).

The material of the grain range below 4 mm of 126 t / h is a fluidized bed cooler (9) (Company Escher Wyss, Ravensburg) abandoned, cooled to about 500C and then subjected to the final screening (10), with 59 tlh under 0.8 mm separated and fed to the intensive mixer (2) for humidification.

The sieved finished product with a grain size of 0.8 to 4 mm in height 67 tlh is transported to the storage shed.

In the procedure described, a granulate yield of 53% worked and the PK fertilizer produced has a nutrient ratio of 10% P205 and 20% K2O.

Example 2 47.2 t / h of Thomas phosphate (13.5% P205) with 22, 6 tlh of filter-moist chloride potash fertilizer salt (60% K20, 12.4% moisture) in one Intensive mixer (1) (Lödige, Paderborn) mixed, the mixture being a resulting total moisture of 4%. A PK fertilizer is created with a nutrient ratio of 10% P2O5 and 15 OJo% K2O.

All other details are identical to Example 1.

Example 3 27.5 tlh Thomas phosphate (16% P2O5) with 18, 35 t / h filter-moist chloride potash fertilizer salt (54% K2O, 10% moisture) mixed in an intensive mixer (1) (Lödige, Paderborn), the mixture has a resulting total moisture content of 4%.

In another intensive mixer (2) (Lödige, Paderborn) is the total return material from stage 9 of 63.5 tlh with the addition of 2.65 tlh salt solution adjusted to a humidity of 4%, the pre-moistened substances are in a common bunker (3) is given, from where it is fed to two screw granulators (4) (Büttner-Schilde-Haas, Hersfeld). In these screw granulators they are mixed intensively and with the addition of a further 8.8 t / h salt solution, d. H. pre-granulated with a total moisture content of 11%.

A hard salt mother liquor is used as the salt solution in the examples Used potash industry.

The pre-granulated mixture becomes a granulating drum in free fall (5) abandoned. This is at an incline of 100 to the horizontal and operated at a speed of 10 min -1.

The moist granulate is fed into a drying drum (6) in which it is gently dried. The dried goods leave the drying area with a Outlet temperature of about 1200 C.

The oversized grain is then screened off over 4 mm on a sieve (7), in a mill (8) ground and the comminuted material returned to the sieve (7).

The material in the grain range below 4 mm (107.5 tlh) is placed in a fluidized bed cooler (9) (company Escher Wyss, Rav-ensburg) abandoned, cooled to about 50OC and then subjected to the final screening (10), with 63.5 t / h separated and under 0.8 mm fed to the intensive mixer (2) for humidification.

The sieved finished product with a grain size of 0.8 to 4 mm in height of 44 tZh is transported to the storage shed.

In the procedure described, a granulate yield of 41% worked and the PK fertilizer produced has a nutrient ratio of 10% P205 and 20 W K2O.

Example 4 37.5 t / h of Thomas phosphate (16% P205) with 25 tZh filter-moist chloride potash fertilizer salt (54% K2O, 10% moisture) in an integral mixer (1) (Lödige, Paderborn) mixed, the mixture has a resulting total moisture content of 4%.

In another intensive mixer (2) (Lödige, Paderborn) is the total return material from stage 9 of 61 tlh with the addition of 2.55 t / h salt solution adjusted to a humidity of 4%. The pre-moistened Fabrics are placed in a common bunker (3), from where they are transferred to two screw granulators (4) (Büttner-Schilde-Haas, Hersfeld). In these screw granulators they are mixed intensively and with the addition of a further 9.95 t / h salt solution, d. H. pre-granulated with a total moisture content of 11%.

The pre-granulated mixture becomes a granulating drum in free fall (5) abandoned. This is done with an incline of 200 to the horizontal and operated at a speed of 15 min.

The moist granulate is fed into a drying drum (6) in which it is gently dried. The dried goods leave the drying area with a Outlet temperature of about 120 O C.

The oversized grain is then screened off over 4 mm on a sieve (7), in a mill (8) ground and the comminuted material returned to the sieve (7).

The material of the grain range below 4 mm of 121 tlh is placed in a fluidized bed cooler (9) (Company Escher Wyss, Ravensburg) abandoned, cooled to around 500C and then subjected to the final screening (10), with 61 t / h separated under 0.8 mm and the Intensive mixer (2.) for humidification.

The sieved finished product with a grain size of 0.8 to 4 mm in height of 60 t / h is transported into the storage shed.

In the procedure described, a total yield of 49.5% worked and the PK fertilizer produced has a nutrient ratio of 10 % P205 and 20 «0 K2O.

Example 5 23.7 tlh Thomas phosphate (16 o P2O5) with 15.9 t / h of filter-moist chloride potash fertilizer salt (54% K2O, 10% moisture) in one Intensive mixer (1) (Lödige, Paderborn) mixed.

The moist fresh material and the dry return material in one quantity from 67.5 tlh are given into a common bunker (3), from where they open two screw granulators (4) (Büttner-Schilde-Haas, Hersfeld-) divided will. In these screw granulators they are mixed intensively and with additives of 11.4 tih saline solution, i.e. H. pre-granulated with a total moisture content of 11%.

The pre-granulated mixture is freefalled into a granulating drum (5) abandoned. This is at an incline of 100 to the horizontal and operated at a speed of 10 min 1.

The moist granulate is fed into a drying drum (6) in which it is gently dried. The dried goods leave the drying area with a Outlet temperature of about 120 ° C.

The oversized grain is then screened off over 4 mm on a sieve (7), in a mill (8) ground and the comminuted material returned to the sieve (7).

The material of the grain range below 4 mm of 105.5 t / h becomes a fluidized bed cooler (9) (Company Escher Wyss> Ravensburg} abandoned, cooled to around 500C and then subjected to the final screening (10), with 67.5 t / h separated and under 0.8 mm are fed to the feed hopper (3).

The sieved finished product with a grain size of 0.8 to 4 mm in height of 78 tih is transported to the storage shed.

In the procedure described, a granulate yield of 36% worked and the PK fertilizer produced has a nutrient ratio of 10% P205 and 20% K2O.

The implementation of the process of the invention according to Example 1 shows with a granulating drum incline of 200 and a speed of 10 min-l in Combination with the separate preprocessing of the feed and return goods a yield of 53 ffi of granules.

If the incline of the granulating drum is changed to 100 a yield of 41% was still achieved.

If the inclination of 20 ° according to Example 1 is retained, but the Speed is increased to 15 min l, the yield of granules is 49.5 k.

The procedure according to Example 5, however, shows an inclination and The speed of the granulating drum according to Example 7 indicates a decrease in the yield Granulate to 36, as no pre-moistening of the return material from level 9 took place.

The technical progress of the method of the invention is opposite the mode of operation according to the state of the art is therefore considerable.

The method of the invention is used for mixing the feed material in step 1 according to example 1 practically dry potash fertilizer salt. In the examples 2 to 5 filter-moist potash fertilizer salt is added according to the working method of the modification of the Method according to claims 1 and 2 used.

The granulating drum of the procedure according to Examples 1 to 5 has a diameter: length ratio of 1: 2.7 for a total length of 6 m on.

The change in the inclination of the granulating drum to over 100 results to increase the throughput of the material to be granulated, resulting in a deterioration the yield of granules is to be expected.

It is surprising that due to the separate pre-moistening of the return material in connection with the higher inclination of the granulating drum after the process er Invention an increase in throughput while improving the yield of granules is achieved.

Claims (3)

P a t e n t a n 5 p r ü c h e 1. Process for increasing throughput capacity and yield the granulation of a PK fertilizer based on Thomas phosphate and potash fertilizer salt by continuously mixing the starting materials with the addition of water or Salt solutions to adjust the granulation moisture through build-up granulation in the Granulating screw and drum, drying, sieving, for separating the finished granulate, Return of the undersized grain and the comminuted oversize grain, characterized by the following process stages: 1) continuous mixing of the Thomas phosphate with practically dry Kalldüngesalz with about 50 --60% K20, 2) pre-moistening of the mixture 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 the mixture calculated, 4) introduction of the pre-moistened substances from the stages 2 and 3 in the screw granulator and residual humidification to about 9-13% by weight of total water, calculated on the mixture, 5) Entry of the pre-granulated mixture from stage 4 into the granulating drum with over 100 to 240 inclination to the horizontal with a Rotational speed of over 8 - 15 min1, 6) Drying of the moist granulate at an outlet temperature of about 10-14o0C, 7) sieving off the hot oversized grain, Comminution and return to the sieving, ~ 8) Separation of the Granulate and cooling to 3o - 6o0C, 9) Return of the return material for pre-moistening in stage 3. 2. The method according to claim 1, characterized in that the amount of the return material from level 9 approx. 35 - 6o% of the total amount of the pre-moistened Substances in level 4 is. 3. Modification of the method according to claims 1 and 2, thereby characterized in that chloridic potash fertilizer salt with about 7-14%, preferably with 12% water, calculated on the potash fertilizer salt, is used in level 1 and the pre-moistened substances are introduced in stage 4. ; Device for carrying out the method according to claims 1 to 3, characterized in that the granulating drum has a ratio of diameter : Length of 1: 2.5 -3, preferably with a length of @ -10 m.