PEDOSPHERE-IMPROVING GRANULATE, METHOD FOR PRODUCING SAME, AND USE THEREOF

Abstract

A method for producing a pedosphere-improving granulate (6) and granulate itself, the method includes a) producing a raw material dispersion including at least one inorganic secondary phosphate (1) and at least one reaction agent (2) in a liquid phase (4), b) separating part of the liquid phase (4) from the raw material dispersion, c) granulating and/or extruding the remaining raw material dispersion with a reduced liquid phase (4), d) either returning the liquid phase (4) separated in process step b) to process step a) in order to produce a raw material dispersion without at least partly separating (5) heavy metals or at least partly separating heavy metals (7) from the liquid phase (4) separated in process step b) and discharging the heavy metals (7) out of the process and subsequently returning the separated heavy metal reduced liquid phase (4) in order to produce a raw material dispersion in a manner analogous to process step a) and/or returning the liquid phase to process step c), and e) repeating process steps a) to d).

Claims

1. Pedosphere-improving granules (6) produced using a method comprising: a) production of a raw material dispersion comprising at least one inorganic secondary phosphate (1) and at least one reactant (1), the proportion of a liquid phase (4) in the raw material dispersion being greater than 30%, with an incubation time between inorganic ones Secondary phosphate (1) and reactant (2) between 1 to 100 minutes, b) separation of part of the liquid phase (4) of the raw material dispersion, c) granulation, extrusion, or a combination thereof of the remaining raw material dispersion with reduced liquid phase (4), d) either recycling the liquid phase (4) separated in process step b) without at least partially separating heavy metal (5) into process step a) to produce a raw material dispersion or at least partially separating heavy metals (7) from the liquid phase (4) separated in process step b) and discharging these heavy metals (7) from the process with subsequent recycling of the low-heavy metal liquid phase (4) to produce a raw material dispersion analogous to process step a) and/or in process step c) and e) repeating the process steps a) to d).

2. A method for producing a pedosphere-improving granulate (6) comprising: a) production of a raw material dispersion comprising at least one inorganic secondary phosphate (1) and at least one reactant (2), the proportion of a liquid phase (4) in the raw material dispersion being greater than 30%, with an incubation time between inorganic secondary phosphate (1) and reactant (2) between 1 to 100 minutes, b) separation of part of the liquid phase (4) of the raw material dispersion, c) granulation, extrusion, or a combination thereof of the remaining raw material dispersion with reduced liquid phase (4), d) either recycling the liquid phase (4) separated in process step b) without at least partially separating heavy metal (5) into process step a) to produce a raw material dispersion or at least partially separating heavy metals (7) from the liquid phase (4) separated in process step b) and discharging these heavy metals (7) from the process with subsequent recycling of the low-heavy metal liquid phase (4) to produce a raw material dispersion analogous to process step a) and/or in process step c) and e) repeating the process steps a) to d).

3. The method according to claim 2, characterized in that the raw material dispersion before the partial separation of the liquid phase (4) is adjusted so that the solids content is less than 50%.

4. The method according to claim 2, characterized in that that a pH of the raw material dispersion produced before the partial separation of the liquid phase (4) is in a range between 1.5 to 3.5 lies.

5. The method according to claim 2, characterized in that the at least partial separation of heavy metals (7) from the liquid phase (4) separated in process step b) by one or more precipitation reactions and subsequent separation of the precipitation products.

6. (canceled)

7. The method according to claim 2, characterized in that the at least partial separation of heavy metals (7) from the in the process step b) separated liquid phase is carried out by one or more selective separation processes.

8. The method according to claim 2, characterized in that the raw material dispersion with reduced liquid phase (4) from process step b) has a moisture content between 10 and 40%.

9. The method according to claim 2, characterized in that a pH of the raw material dispersion with reduced liquid phase (4) is in a range of 4-8.

10. The method according to claim 2, characterized in that the liquid phase (4) separated in process step b) is fed to an at least partial heavy metal separation (5), the separated liquid phase (4), which has been at least partially cleaned of the heavy metals (7), is then fed into process step a) for the production of a raw material suspension, the reactant (2) being present before or during the return to process step a) can be supplied at least partially to this liquid phase (4), the raw material dispersion with reduced liquid phase (4) after process step b) has a solids content of 40% to 70% and the raw material dispersion is fed to a granulation with reduced liquid phase (4).

11. The method of claim 2, characterized in that the granulation is followed by a fractionation of the nutrient granules (6) produced, a coarse fraction and/or a fine fraction being ground and at least partially feedable to step a), b), c), or a combination thereof.

12. The method of claim 2, characterized in that a total of 1 to 70% crystallization products from a phosphorus elimination of step a), b), c), or a combination thereof is supplied.

13. The method of claim 2, characterized in that drying takes place above 100° C. based on the material temperature during drying.

14. An apparatus for the production of granules according to claim 1 comprising at least one first mixing container for feeding. mixing, or a combination thereof at least the inorganic secondary phosphate (1) and the reactant (2), whereby a raw material dispersion is obtained, either the first mixing container being used for the incubation period, further containers, or a combination thereof being present into which the raw material dispersion is transferred and mixed for the incubation period, at least one separation unit for separating at least part of the liquid phase (4), the separation unit being integrated in the first mixing container or being separate therefrom, at least one granulating/extruding unit for granulation, extrusion, or a combination thereof the remaining raw material dispersion with reduced liquid phase (4) from process step b), further components (3) being able to be supplied in this granulating/extruding unit wherein the raw material dispersion is optionally miscible, with at least one feed unit from the separation unit for transferring the raw material dispersion into the granulating extruding unit, at least one return unit for the separated liquid phase (4) without heavy metal separation (5) or after the partial separation of the heavy metals (7) to the mixing container for producing a raw material dispersion analogous to process step a), to the granulating/extruding unit, or a combination thereof.

15. The apparatus according to claim 14, characterized in that the granulating/extruding unit is an intensive mixer, a granulating plate or a fluidized bed or spouted bed reactor.

16. The apparatus according to claim 14, characterized in that the apparatus comprises a unit for separating the heavy metals (7), in which at least part of the heavy metals can be separated from the liquid phase (4), separated in process step b), and can be discharged from the process, wherein at least one feed unit being removed from the separation unit for transferring the partially separated liquid phase (4) is present in this unit for separating the heavy metals (7).

17. Coated or uncoated fertilizer granules (6) characterized in that the fertilizer granulate (6) comprises at least one inorganic secondary phosphate (1) and a greater than 60% neutral-ammonium citrate-soluble P.sub.2O.sub.5 fraction based on the total phosphate content in the fertilizer granulate (6).

18. The coated or uncoated fertilizer granules (6) according to claim 17, characterized in that the fertilizer granules (6) comprise at least one inorganic secondary phosphate (1), and a greater than 60% neutral ammonium citrate-soluble P.sub.2O.sub.5 fraction based on the total phosphate content in the fertilizer granules (6), the phosphate fraction from the inorganic secondary phosphate (1) in the P.sub.2O.sub.5 fraction has a water solubility of less than 40%.

19. The coated or uncoated fertilizer granules (6) according to claim 17 characterized in that the fertilizer granules (6) have at least one of a total of 0.1 to 25% humic acid, fulvic acid, or their salts, a total of 0.1 to 30% organic acids, or a total of 0.1 to 50% structural substances.

20. The coated or uncoated fertilizer granules (6) according to claim 17 characterized in that the fertilizer granulate (6) has one or more crystallization products from the phosphorus removal in a concentration range between 1 to 70%.

21. Use of the fertilizer granules (6) according to claim 17 for nutrient supply in agriculture, forestry and/or horticulture characterized in that the fertilizer granulate (6) comprises at least one inorganic secondary phosphate (1) and a greater than 60% neutral ammonium citrate-soluble P.sub.2O.sub.5 fraction.

Description

[0207] The invention is described in more detail with reference to the following figures:

[0208] FIGS. 1 and 2 each show a schematic representation of preferred embodiments of the proposed method in two embodiments.

[0209] FIG. 1 describes a preferred embodiment of the proposed method without the optional separation of heavy metals. The preferred embodiment of the proposed method shown in FIG. 1 is preferably referred to as the “basic embodiment” of the method. The basic embodiment essentially makes full use of the procedural advantages of producing the raw material dispersion according to the invention with a high proportion of liquid phase. In contrast to methods from the prior art, a raw material dispersion with a high liquid phase content is first produced, the high liquid phase content advantageously acting as a buffer for the reaction taking place. As a result, the reactions which often occur spontaneously and are sometimes very exothermic when the phosphate-containing secondary raw material is mixed with the mineral acid can be checked and controlled, and the mixture does not show any troublesome stickiness. Only after the reaction between the inorganic secondary phosphate (1) and the reactant (2) has been largely carried out does the further processing to the granulate take place. The reaction of the phosphate conversion is thus advantageously separated from the process of granulation.

[0210] The proposed course of the reaction between inorganic secondary phosphate (1) and reactant (2) in a raw material dispersion with a high proportion of liquid phase has the process engineering advantages described in particular. If the raw material dispersion is to be granulated directly, a very high proportion of water has to be removed by, for example, drying, which is, however, cost-intensive. Accordingly, in the proposed method, part of the liquid phase is circulated and mechanically separated before the granulation and fed back to the manufacture of the raw material dispersion.

[0211] In process step a), a raw material dispersion is generated from at least one inorganic secondary phosphate (1) and at least one reactant (2). For the sufficient reaction between the at least one reactant (2) and the at least one inorganic secondary phosphate (1), an incubation period is awaited, in which case the raw material dispersion can be mixed further. It is provided that the reactant (2) reacts at least with parts of the phosphate introduced by the inorganic secondary phosphate (1) in order to increase the solubility and plant availability of this phosphate. In process step a), additional components (3), such as, for example, nutrient-containing components, dispersing and defoaming agents, structural materials, agents for pH adjustment, urease inhibitors, ammonium stabilizers and/or water, can be added to the raw material dispersion. The liquid phase (4) at least partially cleaned of heavy metals in process step d) can also be supplied and used, for example, to adjust the solid-liquid ratio.

[0212] In process step b), part of the liquid phase is separated from the raw material dispersion produced in process step a) and process step d) is added. The remaining residue from the solid or undissolved portion of the raw material suspension with the remaining portion of the liquid phase, which is preferably not separated off, is fed to process step c).

[0213] In process step c), the granulation and/or extrusion of the remaining raw material dispersion takes place with reduced liquid phase from process step b). Depending on the liquid-solid ratio set, different granulation or extrusion processes can be used. Before and/or during the granulation, further components (3) and/or low-heavy metal liquid phase from process step d) can be added. This process step c) results in soil- and plant-specific fertilizer granules (6) with an adjusted and constant nutrient composition, whereby inorganic secondary phosphate, such as sewage sludge ash, can be used at least as a nutrient source, the phosphate contained therein being made particularly readily available to plants by the action of the reactant and the heavy metals contained in the inorganic secondary phosphate are at least partially separated off.

[0214] In process step d), the liquid phase (4) is recycled to produce a raw material dispersion analogous to process step a).

[0215] Process steps a) to d) are repeated as often as desired, which is preferably referred to as process step e).

[0216] FIG. 2 shows a preferred embodiment of the proposed method comprising an at least partial separation of the heavy metals. In contrast to the preferred embodiment of the method shown in FIG. 1, in process step a) the reactant (2) is not only reacted at least with parts of the phosphate introduced by the inorganic secondary phosphate (1), but also the reactant (2) extract the highest possible proportion of heavy metals from the inorganic secondary phosphate (1).

[0217] Process steps b) and c) are essentially comparable to the embodiment of the invention shown in FIG. 1. In process step d), however, heavy metals (7) are at least partially separated from the liquid phase separated in process step b) and these heavy metals (7) are removed from the process, the low-heavy metal liquid phase (4) subsequently being used to produce one Raw material dispersion analogous to process step a) and/or can be returned to process step c). Different methods can be used to separate the heavy metals, depending on the type and concentration of the heavy metals to be separated or the conditioning of the separated liquid phase from process step b). Depending on the type of separation process, additives for separating heavy metals (5), such as precipitants and flocculants, pH adjustment agents, sacrificial metals and/or extraction agents are used. Process steps a) to d) can be repeated any number of times

LIST OF REFERENCE NUMBERS

[0218] 1 inorganic secondary phosphate [0219] 2 reactants [0220] 3 other components [0221] 4 liquid phase [0222] 5 heavy metal separation [0223] 6 fertilizer granules [0224] 7 heavy metals