CS260482B1 - A method for treating phosphorus-containing solid residues - Google Patents

Abstract

A mixture consisting of solid residues containing phosphorus, water-soluble phosphate salts or salt and water is brought into contact with moving solid particles, the amount of which represents at least 25% by weight of the dry matter of the residues, while drying and/or separation are carried out simultaneously or/and after mixing. The product is a phosphorus-containing fertilizer suitable for application in acidic soils.

Description

The invention relates to a process for processing phosphorus-containing solid residues into fertilizer.

So far, such residues, for example when neutralizing the extracting trihydrogenphosphoric acid with ammonia, sodium hydroxide, etc., or reducing the fluorine content of water-soluble phosphoric salts with calcium raw materials, are not treated even though they contain a considerable amount of phosphorus.

This disadvantage is overcome by a process for the treatment of phosphorus-containing solid residues, which comprises preparing a mixture containing at least 1% by weight of these residues. % water-soluble phosphate salts or salts; and 10 to 75 wt. water, which is contacted with physiologically acceptable moving solid particles containing preferably plant-utilizable components and / or soil improvers, the amount of which is at least 25% by weight; and / or after mixing, drying and / or separation and / or granulation are carried out.

Preferably, liquids are added.

During processing, the feedstock or feedstocks containing the compound or compounds which react with or form hydrates and have a positive effect in crop production are preferably added.

Advantageously, nutrient and / or trace constituents of importance for plant nutrition and protection and / or substances improving the physicochemical properties of the soil are added.

Preferably, natural phosphate is added, preferably in micronized form.

Advantages are added to improve the physical properties of the product.

The basic effect of the process according to the invention is that it is utilized for plant nutrition by phosphorus which is contained in the solid residues that are lost in the production of pure water-soluble phosphoric salts from the trihydrogenphosphoric acid extraction acid.

The manufacture may be continuous, discontinuous or a combination of both. For example, wet unswashed or partially washed residues are brought into contact with moving solid particles such as dolomite and / or feldspar etc. in a rotary drum, while simultaneously drying and then separating. During the process, it is possible to add feedstocks containing the compound or compounds which react with water or form hydrates, other nutrient components, substances containing trace elements or improving the physical-chemical properties of the soil or the physical properties of the fertilizer.

The process according to the invention is described in more detail below with reference to a specific embodiment.

Example

Moisture-free solid residues from the production of pure ammonium phosphates, containing 60% by weight % solids, 28 wt. water, 10 wt. % ammonium dihydrogen phosphate and 2 wt. dibasic ammonium phosphate were added in an amount of 20 percent by weight. to milled dolomite having a particle size of from 0.063 to 5 mm in a rotating drum while drying with hot air at a temperature of about 130 ° C. The process resulted in partial pelletization.

The phosphorus-containing calcium-magnesium fertilizer obtained is particularly suitable for application in acidic soils.

Claims (6)

OBJECT What is claimed is: 1. A method for treating phosphorus-containing solid residues, comprising preparing a mixture comprising at least 1% by weight of said phosphorus residues. water-soluble phosphate salts or salts and 10 to 75 wt. water, which is brought into contact with moving physiologically acceptable solid particles, preferably containing plant-useful ingredients and / or improving soil properties of at least 25% by weight. drying and / or de-agglomeration or granulation is carried out simultaneously with mixing and / or mixing. 2. The method of claim 1, wherein liquids are added. 3. A process according to claim 1, wherein the feedstock or feedstock containing the compound or compounds reacting with water or forming hydrates and having a positive effect on crop production is added during processing. 4. A method according to any one of claims 1 to 3, wherein further nutrient and / or trace components important for plant nutrition and protection are added and / or. substances improving the physico-chemical properties of the soil. 5. A process according to any one of claims 1 to 4 wherein natural phosphate is added, preferably in micronised form. 6. A method according to any one of claims 1 to 5, characterized in that substances improving the physical properties of the product are added.