CS212023B1 - Method of physical cleaning of fluid fertilizers - Google Patents

Abstract

A method of physical liquid purification extractive acid based fertilizers phosphoric acid. For liquid fertilizer is added for every 100 parts by weight 0.01 and 5.0, preferably 0.025 to 0.5 wt and / or chemically modified carboxyalkyl cellulose and the mixture thus obtained is subjected to sedimentation, centrifugation or filtration, while substantially increasing the rate of sedimentation solid dispersed parts. Is a it is preferable to add carboxyalkylcellulose in 0.5 to 5% aqueous solution; colloidal dispersed coagulation occurs particles into clusters while being dependent colloid-dispersed character the particles with the podium density of the impurity they settle on the surface or on the sedimentation bottom container. By vigorous stirring a "sharp" phase separation is achieved.

Description

The invention relates to a process for the physical purification of liquid fertilizers prepared on the basis of phosphoric acid extraction.

Liquid multicomponent fertilizers produced from extractive phosphoric acid of various provenance are usually dark brown to black colored, which is caused by the presence of colloidal dispersed organic substances and carbonaceous particles. In addition to these organic substances, dissolved impurities, predominantly its ferrous, ferric, calcium, aluminum or magnesium salts, and others.

The type and amount of colloidal dispersed solid and dissolved impurities in the phosphoric acid extract and hence in the liquid multicomponent fertilizers produced from it depend on the provenance of the phosphate, the method of its treatment as well as the technology of phosphate processing to extract phosphoric acid. Due to the colloidal nature of the solid particles and the presence of solutes which are excreted from the liquid multicomponent fertilizers in the first storage phase, their sedimentation rate is very low, which makes separation methods such as sedimentation, filtration or centrifugation poorly effective.

The dissolved impurities deposited in the amorphous form gradually progress to the crystalline form, resulting in the formation of a solid compact sediment, which causes handling and application difficulties. These difficulties associated with the formation of both amorphous and crystalline sludge can be multiplied by mixing different kinds of liquid fertilizers. ¹

At present, flocculation of fine particles into larger silicon-aggregates by the addition of flocculating agents is used to accelerate the sedimentation of solid colloidal dispersed particles. based on synthetic polyacrylamide resins (foreign flocculants known under the trade names Tiofloc, Separan, Praestol and others). The addition of finely ground phosphate (US Pat. Off. 818 819, 1969), a water-insoluble aliphatic amine (US Pat. 3,630,711, 1977), a mixture of tall oil amines and a quaternary ammonium chloride (JM) is used to remove carbonaceous impurities from ammoniacalized phosphoric acid. Stinson, HC Mann, Jr., KE Mc Gill: Clarification of Black Liquid Fertilizer Madl from Wet-Process Superphosphoric Acid - Lecture at the Meeting of the American Chemical Society, Chicago, Illinois; 1975) and Others of Sedimentation Accelerators 129170).

Although the flocculants used to physically purify liquid fertilizers are relatively effective, their widespread use on an industrial scale is often quite limited, given that they are relatively expensive and not always available formulations.

It has now been found that liquid multicomponent fertilizers prepared on the basis of extraction phosphoric acid can be clarified as well as flocculating agents according to the invention.

The principle of the invention is that 0.01 to 5.0, preferably 0.025 and 0.5 parts by weight of 0.5 to 5 are added to each 100 parts by weight of the liquid fertilizer prepared on the basis of extractive phosphoric acid. % aqueous solution of carboxymethylcellulose or carboxyethylcellulose and the resulting mixture is subjected to sedimentation, centrifugation or filtration.

According to the invention, it is possible to substantially increase the sedimentation rate of the solid dispersed particles by adding carboxymethylcellulose or carboxyethylcellulose and to obtain from so-called liquid phosphorous multi-component fertilizers the so-called " black type clear products usually green.

Add 0.5 to. A 5% aqueous solution of carboxymethylcellulose or carboxyethylcellulose to the liquid fertilizer coagulates the colloidally dispersed particles into agglomerates which sediment relatively quickly. The rate of sedimentation of the particles and the color of the final liquid fertilizer largely depend on the solids content of the original solution. Depending on the nature of the colloidally dispersed particles, it is. Depending on the specific gravity, the impurities settle on the surface or bottom of the sedimentation vessel. Intensive mixing of the mixture of liquid fertilizer and carboxyalkyl cellulose solution results in a "sharp" phase separation.

The physical purification of the liquid fertilizers according to the invention results in a substantial increase in the sedimentation rate of the colloidal dispersed solid particles in the liquid fertilizer solution.

A further advantage of the method according to the invention is the possibility of replacing expensive and usually hardly available flocculants.

The flocculated sludge can be utilized as an additive to solid or suspension multicomponent fertilizers.

A great advantage of the method of physical purification of liquid fertilizers according to the invention is that the substances used favorably influence the storage and handling properties of the liquid multicomponent fertilizers, are completely biodegradable and completely biodegradable. are not harmful to health.

These examples illustrate but do not limit the invention in any way.

Example 1

250 parts by weight of liquid multicomponent ammonium polyphosphate fertilizer prepared from phosphoric acid extract, so-called phosphoric acid, were introduced into the sedimentation cylinder. Black Type Specified as follows:

total nitrogen content by mass: 11,0 total P2O5 content by mass: 38,0 pHao ° c = 6,32 specific gravity d2o ° _c = 1442,2 kgm ' ³

To a solution of the ammonium polyphosphate was added 0.63 parts by mass of a 5% aqueous solution of carboxymethylcellulose, i.e. the sodium salt of celulózoglykolovej domestic production of the following composition: active compound content in mass%, at least: ¹ dry matter content of 62 mass% of at least 90 mass alkalinity of 4 insoluble residue in% by weight maximum:

The mixture was shaken vigorously and the time course of sedimentation was monitored. After 12 hours of standing, the mixture was separated, with the coagulated particles settling in the bottom. 229 parts by weight of a green ammonium polyphosphate solution were obtained. The sediment settled at the bottom of the cylinder and accounted for 4.1% of the total volume of clarified liquid fertilizer.

Example 2

The procedure was analogous to Example 1.

250 parts by weight of ammonium polyphosphate solution of pH - 6,12 with a specific weight of ¢ 20 ° _{C -} 1386,2 kgm ^-3 containing 10% by weight of total nitrogen and 34% by weight of P2O5 prepared from phosphoric acid extract. of a black type was mixed with 25 parts by weight of a 5% aqueous solution of carboxyethylcellulose of the following composition:

active ingredient content in weight% at least: 60 dry matter content in weight% at least: 90 alkalinity in weight% maximum: 5 insoluble residue in weight% maximum: 10

After 16 hours of standing, 201.1 parts by weight of a clear solution of bright green color were obtained. The volume of sediment represented

23.5% by volume of the total volume of the clarified solution.

Example 3

250 parts by weight of liquid ammonium polyphosphate fertilizer prepared from phosphoric acid extraction so-called. black and containing

10,9% by weight of total nitrogen; and

30.6% by weight of total P2O5 opito ° C = 7.0 and specific gravity d 20 ° _C = 1349.2 kgm ^-3 were added 25 parts by weight of a 5% aqueous solution of carboxymethylcellulose. After vigorous stirring and standing, 197.1 parts by weight of a clear green solution were obtained after 16 hours. The sediment accounted for 23.4% of the total volume of the clarified solution.

Example 4

To 250 parts by weight of an orthophosphate - type liquid fertilizer of the orthophosphate type

8.0% by weight of total nitrogen and 24.0% by weight of total P2O5 having a pH of ₂₀ ° c = 6.85 and a specific weight of d20 ° C of 1317 kgm ^-3 were added 1.25 parts by weight of a 5% aqueous solution of carboxymethylcellulose and the mixture was shaken vigorously. After standing for 7 hours, the phases were separated to give 176.5 parts by weight of a milky, greenish solution. The multi-layered sediment sedimented at the bottom of the vessel to make 29.7% of the total volume of the clarified solution and a specific gravity d ₂ ° C = 1357.5 kgm ^-3 , 1.25 parts by weight of a 5% aqueous carboxymethylcellulose solution was added, and the mixture was shaken vigorously. After 7 hours, the phases were separated to give 176.5 parts by weight of a milky, greenish solution. The multi-layered sediment sedimented at the bottom of the vessel and was 29.7% of the total volume of the clarified solution.

Claims (1)

Process for the physical purification of liquid fertilizers prepared on the basis of extractive phosphoric acid, characterized in that 0.01 to 5.0 is added to the liquid fertilizer for every 100 parts by weight, with a yield of 0.025 to 0.5 parts by weight of 0.5 to 5% by weight aqueous solution. solution of carboxymethylcellulose or carboxyethylcellulose and the mixture thus obtained is subjected to sedimentation, centrifugation or filtration.