CS214637B1 - The method of physical cleaning of liquid fertilizers - Google Patents

Abstract

Method for physical purification of liquid fertilizers prepared on the basis of extractive phosphoric acid;) by adding to the liquid fertilizer for every 100 parts by weight 0.5 to 10.0, preferably 1.0 to 5.0 parts by weight^ of a precondensation mixture containing urea and acetaldehyde in a molar ratio of 0.5 to 1.5 or of acetaldehyde alone and the mixture thus obtained is subjected to sedimentation, centrifugation or filtration. Intensive mixing promotes the separation of the mixture into a liquid and solid phase. The time required for complete sedimentation of colloidally dispersed and dispersed parts varies with the type of liquid fertilizer or the origin of the acid and the amount of added precondensation mixture or acetaldehyde.

Description

1,214,637

BACKGROUND OF THE INVENTION The present invention relates to a process for the physical purification of liquid fertilizers based on phosphoric acid, based on a pre-condensation mixture containing urea and acetaldehyde or ammonium acetaldehyde.

Liquid multicomponent fertilizers made from commercial phosphoric extraction acid contain a relatively large proportion of solid dispersed particles and dissolved impurities derived from the raw materials and reagents used in the phosphate decomposition process of phosphates. <

Impurities that accumulate in liquid fertilizers, phospho-acid extraction acid bases typically typically stain and are the source of many technological difficulties.

They cause colloidal dispersed sludge to form a crystalline form during long-term storage. This transformation results in the formation of complicated hard resuscible ducts which cause problems in the handling and storage of liquid fertilizers.

Flocculants and additive materials (U.S. Pat. No. 3,630,711, 1977, U.S. Pat. No. 2,988,504, 1961) are currently used to accelerate colloidal dispersion particles coagulation. 1979 / ·

The principle of the physical cleaning of liquid fertilizers according to the invention is that for every 100 parts by weight of liquid fertilizer, 0.5 to 10.0, preferably 0.5 to 1.5, parts by weight of the precondensation mixture containing urea and acetaldehyde in molar ratio is added. 0.5 to 1.5 or acetaldehyde alone, and the mixture thus obtained is grayed out by centrifugation or filtration. intensively mixing promotes liquid and solid phase separation. The precondensation mixture of urea and acetaldehyde causes rapid coagulation of the dispersed solids and is sedimentation.

The main advantage of the process of physical purification of liquid fertilizers according to the invention is that the addition of a precondensation mixture of urea and acetaldehyde substantially increases the rate of sedimentation of solid dispersed particles and liquefied multi-component fertilizers of the so-called black type, compared to the commonly used flocculants. those usually green fayby. According to the invention, it has been found that the time required for complete sedimentation of the dispersed dispersed particles varies with the type of liquid fertilizer or acidity and the amount of pre-condensation mixture or acetaldehyde added. substitution of relatively expensive and to a limited extent flocculants · Sediment containing predominantly carbonaceous impurities can be evaluated by addition to solid or suspension fertilizers.

The methods for the physical purification of liquid fertilizers according to the invention are, but are not limited to, the examples. EXAMPLE 1 To 250 parts by weight of ammonium polyphosphate-based liquid fertilizer prepared from phosphoric acid extraction acid, a 25 wt.% Pre-condensation mixture consisting of urea crystal and acetaldehyde was added, obtained by mixing both components in a urea 1 acetaldehyde 1 molar ratio. i 0.9; The ammonium polyphosphate solution was specified as follows: 10% by weight of total nitrogen. 34 wt% ^ 2 ° 5 pH. 6.12 specific gravity d 20 ° C 386.2 kg.m ”· ^.

The reaction mixture was vigorously stirred mechanically, transferred to the sedimentation valoa and not allowed to stand. The time course of sedimentation was harmonized. After only 2 hours, the mixture was separated, giving 249.5 parts by weight of pure ammonium polyphosphate green fabry. A substantial portion of the impurities sedimented at the bottom and formed 17.7% by volume of the bulk volume.

Claims (1)

SUMMARY OF THE INVENTION Process for the physical purification of liquid fertilizers prepared on the basis of extraction phosphoric acid, characterized in that 0.5 to 10.0, preferably 1.0 to 5.0 parts by weight of the precondensation mixture containing urea and acetaldehyde are added to the liquid fertilizer every 100 parts by weight. in a molar ratio of 0.5 to 1.5 or of oetaldehyde alone and the mixture thus obtained is subjected to sedimentation by centrifugation or filtration.