DE2601677A1 - Fertiliser prodn. from ashed waste products - by mixing with sulphur - Google Patents

Abstract

Prodn. comprises mixing the hot finely divided ash with S (pref. wet-ground) to give an S:P2O5 ratio of pref. 0.714:1. The starting as pref. contains 3-30% (esp. 10-18%) P2O5 and 0.5-35% K2O. It can be used at a temp. (a) above or (b) below the m.pt. of sulphur. In case (a), the components are simply granulated together. In case (b), the components are granulated with an aq. binder soln. and the product is dried and/or cooled. The process can be used to produce granular PK or NPK fertilisers from incinerated sewage sludge, animal waste, refuse and other P-contg. wastes.

Description

"Process for the production of a fertilizer from ashed

Waste products "The incineration of waste products such as Fresh, Paul or sewage sludge, waste of animal origin, garbage, garbage compost and other waste containing P in the known incineration plants In addition to CaO, SiO2 and many other substances, ash also contains 3 - 30%, preferably 10-18% P205 and 0.5 "35% K2O.

The subject of the present invention is that of the ashes .. This also includes fly ash - containing phosphates and kali as a fertilizer to make usable. This is achieved by finely grinding ashes into still hot state is mixed with sulfur, with 1 part by weight of P2O5 0.714 Parts by weight of sulfur must be used.

It is known that finely divided, elemental sulfur is caused by certain Microorganisms in the soil are attacked and exydiert. This process has become the The present invention made use of by hot, preferably to the melting temperature Ashes cooled by sulfur with sulfur, preferably such that, because of the at Grinding existing risk of ignition, wet grinding, mixed and is granulated with water or aqueous binder solutions.

The ones that were still hot from the previous combustion process and, if applicable cooled ash causes evaporation of the introduced water nd.

as long as temperatures are still present that are required to melt the sulfur cause the molten sulfur to bind with the ash.

After cooling down, the granules obtained fall into hard form and abrasion-resistant, r shape. At temperatures below the melting temperature of the Sulfur, bring in contrast added binder solutions or, if used, too of urea or ammonium nitrate melting at elevated temperatures, according to their Recognize in the mix or

the desired hardening in the granulate, similar to the higher one Temperatures melted and then solidified sulfur, for hardening which leads to granules.

If the ash-sulfur granules obtained in this way get into the ground, then the P component contained in them is there by the under the influence of Soil bacteria, the sulfur was oxidized or broken down into plant-soluble ones Form and can thus be fully used as K2O-containing P2O5 fertilizer or PK fertilizer become effective, this effect through the further contained proportions of CaO and SiO2 is still increased.

In the production of such ash-sulfur granules it has been shown that that the plant physiological effect is best when the melting temperature of sulfur is not exceeded as far as possible.

When using binder solutions, the sulfur remains in the ash-sulfur granules obtained in finely divided form, which compared to the molten form the large The advantage is that it can take effect more quickly in the soil.

The proportion of P205 and K2O in the resulting ash can, depending on Origin, be different, It has therefore proven to be advantageous to use the nutrient content, if necessary, by adding a little high phosphate flour and / or small amounts of potash salts 0 It goes without saying, if NPK mixed fertilizer is desired also still possible to add nitrogen salts, which then, They can be made to melt, which is easy to remove when using no ash is possible, can serve as a binder in the same way as when using of aqueous binder solutions. the melting sulfur is the case.

Example 1 88 parts by weight of a 9.4 ffi P205 and 28.5% K2O containing, Garbage ash still at 105 ° C is mixed with 12 parts by weight of a 50% aqueous Suspensions of wet-ground sulfur i @@ ig mixed and then with the addition of 12% of a water gall solution of 80BQ granulated.

In this way, a fertilizer granulate is created from which one can the moisture dries out, whereby the energy source for the drying process is the waste heat generated by incineration is used. After drying, the granules had 8.2% P205, 25% K2O and 6% sulfur. After introducing these granules into the Soil it breaks down quickly and the soil bacteria oxidize the sulfur, whereby the finely powdered phosphate is autgeschloäsen. After a while, you can face it "Unfertilized," find a good fertilizing effect on that under the influence of bacteria P205 that have become plant-soluble and the K20 must be returned.

Example 2 Solid dry bed sludge is made in a vortex furnace verasoht and you get a 15.8% P2O5 and 5.8% K2O containing, after some Storage time still 165 ° C hot ash, which in a plate granulator with 11.5 wt .-% finely divided sulfur are brought together, whereby the sulfur melts and At the same time, the droplets that are formed combine with the ash particles. After cooling down, fine grains develop, which are exposed to bacteria in the soil @ llmähli @ h digest the phosphate it contains so that it is citric acid soluble will. The fertilizing effect is compared to the granules produced according to Example 1) however delayed.

Example 3 In a deck roasting oven, a mechanically pre-dewatered Sewage sludge and what was garbage separated by a recycling plant Constituents of the mixture burned.

75 parts by weight of the resulting 11.9% P2O5 and 16.2% K2O containing, still about 120 ° C hot ash with 15 parts by weight of one to 90 % Passage through a sieve with 1600 Macshen / cm2 ground Moroccan phosphates (34 % P205) and 10 parts by weight of finely powdered sulfur and 10 parts by weight of ammonium nitrate (35% N) intimately mixed and the resulting mixture at about 165 ° C, the melting temperature of ammonium nitrate, granulated0 After cooling, hard and abrasion-resistant products are obtained Fertilizer granules with 3.5% N, 14 ffi P205 and 10% K20.

Claims (5)

Claims: 1) Veranren for the production of a fertilizer from ashed Waste products, characterized in that finely trimmed, still hot ash with preferably wet-milled sulfur is mixed, with 1 part P205 being preferred 0.714 parts of sulfur are used and the K2O contained in the ash is also related. 2) Method according to claim 1), characterized in that the in the sulfur contained in the mixture due to the sulfur present in the related hot ash Temperatures melted and in this state granulated together with the ash and the granules obtained are cooled. 3) Method according to claim 1) and 2), characterized in that the ash used is cooled below the melting temperature of the sulfur and then the mixture with aqueous binder solutions or with concomitant use granulated by nitrogen salts melting at elevated temperature and the obtained Granulate is dried and / or cooled. 4) Method according to claim 1) to 3)> characterized in that the ash-sulfur mixture to adjust the P205-izvo K2O content Rock phosphate flour and / or potash salts and, for the production of an NPK fertilizer, Nitrogen salts can still be added. 5) Method according to claim 1) to 4), characterized in that the phosphates in the granules obtained are oxidized in the soil under the influence of bacteria and be made plant-soluble.