CS231122B1 - A method for producing liquid phosphate and nitrogen additives for animal nutrition - Google Patents

Abstract

The invention describes the technology for producing a mineral liquid feed additive with a low arsenic and fluorine content by refining fertilizer ammophos, an impure salt mixture with a predominant proportion of NH^HgPO^. Ammophos is boiled in water, possibly oxidized, and the resulting arsenate is coprecipitated with basic ferric phosphate by the possible addition of a ferric salt. The fluorine contained in the leachate is converted into hexafluoroaluminate by the addition of an aluminum salt, which is precipitated as cryolite with sodium salt or hydroxide. The clear filtrate as a solution of NH^HgPO^ with a proportion of (NH^jgHPO^ is adjusted according to feed recipes as needed.

Description

(54)

Process for producing liquid phosphorus and nitrogen additives for mineral nutrition of animals

The invention describes a technology for producing a mineral liquid feed additive with a low content of arsenic and fluorine by refining fertilizer amophos, an impure salt mixture with a predominant NH4HgPO4 content. Amofos is boiled in water, eventually prooxidized, and the arsenate formed is co-precipitated with basic iron phosphate by the possible addition of ferric salt. The fluorine contained in the leachate is converted to hexafluoroaluminate by addition of the aluminum salt, which is precipitated as the cryolite with sodium salt or hydroxide. The clear filtrate as a solution of the NH4HgPO4 salt containing (NH4HgPO4) is adjusted as necessary to feed formulas.

231 122 (11) (Bl) (51) Int Cl '

A 23 Κ 1/175, C Ol B 25/28

231 122

231 122

The invention relates to a process for the production of an aqueous solution of ammonium phosphates which, by its quality, satisfies the mineral nutritional needs of animals or microorganisms in fermentation.

For feed phosphates, the degree of contamination by fluorine, arsenic and lead is critical. The CSSR assumes a maximum concentration of 0.1% F, 7 ppm As and 18 ppra Pb · For liquid feed additives whose active ingredient content is dependent on the degree of dilution of the solution, the proportional permissible concentration of impurities should be considered.

Feed phosphates are prepared mainly by neutralization of thermal phosphoric acid, which is always practically free of fluorine and lead, but not arsenic. The high cost of this acid is due to the extra energy consumption of electric furnaces to reduce natural phosphates,

Neutralization of the more affordable extraction phosphoric acid with ammonia leads to an impure mixture consisting predominantly of ammonium dihydrogen phosphate. It is used under the technical name araofos mainly as fertilizers. Amophos and its aqueous extracts are unsuitable for animal feed because it contains approximately 3% F and 100 ppm As.

The above-mentioned disadvantages of the prior art are largely eliminated by the process for producing liquid phosphorous and nitrogenous additives for mineral nutrition of animals by purifying the technical ammonium phosphate, which is the principle of the invention, which consists in treating feed grade technical ammonium phosphate with water in an amount of 100 to 500% by weight, based on the original batch of ammonium dihydrogen phosphate, at a temperature of from 60 ° C to the boiling point, the resulting suspension or the liquid phase of the suspension is optionally oxidized with an oxidizing agent such as chlorine, alkaline hypochlorite and hydrogen peroxide in an amount of 0; 03 to 6% by weight of the active ingredient, based on the weight of the starting technical feedstock, and optionally treated with ferric salt, in an amount of from 0.03% to 6% by weight of iron relative to the feedstock, preferably an aqueous ferric chloride solution, then an aluminum salt in an amount of 15 to 150% by weight of aluminum relative to the weight of fluorination in the treated solution, preferably solid aluminum sulphate or an aqueous solution thereof, is added, followed by sodium compound, preferably phosphate and / or sulphate; or sodium hydroxide, the precipitated sludge is separated and the filtrate is concentrated or diluted as necessary.

The principle of the invention is that this technical mixture of ammonium phosphates and other salts is extracted with hot or boiling water in an amount which is given by the solubility of the mixture of salts in hot water; about 100 to 500% by weight of water, based on the weight of the feedstock to be treated. The resulting suspension contains insoluble sludge, mainly phosphates and fluorides or fluorosilicates of caustic soils; the amount of sludge depends on the type of amophos being processed. It is advantageous to separate the sludge by separate filtration or sedimentation, wash with hot water and refine the resulting solution. The refining processes described below also take place in a slurry containing the initial sludge, but the reaction of the components in the thick slurry may not be complete. Inclusion of the oxidation operation is possible before and after filtration.

The resulting hot liquor, containing dissolved proportions of the feedstock and the remaining sludge, is oxidized in a conventional manner, preferably with chlorine gas or sodium hypochlorite solution or hydrogen peroxide, so as to convert the iron and arsenic compounds into ferric and arsenic salts. The ferric salt, preferably an aqueous solution of 30% by weight of FeCl 2 used in the water industry, is slowly added to the prooxidized solution with stirring. The amount of ferric salt required depends on the contamination of the raw material; it is desirable to apply 0.03 to 1% by weight of said solution based on the weight of the amofos charge; an excess of precipitant causes losses of the phosphorus component.

The ferric salt in the weakly acidic amophosic slurry hydrolyzes to form ferric hydroxide, which absorbs

231 122 arsenic and produces hardly definable basic iron arsenates. If the previous oxidation is dearsenised, the refining efficiency is lower.

At pH = 4,4 (the pH-value indicated after dilution of the liquid phase of the suspension with distilled water to a solution containing 1 to 2% by weight of the sum of salts) corresponding to a solution of ammonium dihydrogen phosphate in water, even in acidic solutions fluorine hydrolysis virtually ended.

The elimination of fluorine is based on the formation of a sparingly soluble trisodium hexafluoroaluminate salt, known under the mineralogical name cryolite, according to the overall reaction

Na ⁺ + Al ³⁺ + 6 F »Na ₃ AlF _g to which other stoichiometric data also apply.

The required amount of aluminum salt or a solution thereof, preferably commercial aluminum sulphate formulations used in water supply, is added to the hot solution after dissolution of the amophos and possibly dearsenisation. In the first phase, an aluminum phosphate gel is precipitated, which gradually dissolves to form complex ions, especially fluorine-aluminum AlFg.

The fluoride precipitation proceeds optimally when dosing the theoretical amount of the aluminum salt with respect to the analytically determined fluorine content of the solution. Sodium ions are introduced as a suitable salt, preferably hydrogen phosphate or sulfate, and / or as sodium hydroxide. It precipitates in theoretical amounts up to five times the excess sodium compound ·

The conditioned suspension is filtered, the filtrate concentration is adjusted for shipping as required or used as a component for the preparation of the combined feed solutions.

For illustrative purposes, the manufacturing process is described as discontinuous. The production line can be modified as partially or completely continuous. Dearsenisation and defluoration operations are independent of the chemical; the first or second refining performance can be omitted if there is no commercial interest in complete solution cleaning. The production can advantageously be combined with the preparation of crystalline salts of ammonium dihydrogen phosphate or diammonium hydrogen phosphate by elimination of the crystallization operation. 231122

For purposes of illustration, an exemplary embodiment is provided by which the invention is not exhaustive or limited.

1) In diammonium phosphate production plant, trampled, otherwise untreated, amofos extract, in zeno 24.5 g F. and 26 ppm As · was removed from the filter and 6 ml of the working liquor was boiled with 5 ml of a 30 wt.% HgOg solution, slowly introduced with 10 ml of a 1 mol. I ^-! · After eight hours, heated to 80 ° C and under stirring 105 ml admits the aluminum sulfate solution having a concentration of 0.65 mol. After 30 minutes, 82 ml of 5 mol / L sodium hydroxide solution were slowly poured in. The suspension was allowed to sediment, then a sample of 840 ml final solution was taken, filtered through a dry filter and analyzed.

Determined residual contamination 0.78 g F / l and 5 ppm As. Taking into account the dilution factor, about 96% of fluorine and about 75% of arsenic were eliminated.

Claims (1)

SUBJECT OF THE INVENTION 231 122 A process for the production of a liquid phosphorus and nitrogen additive for mineral nutrition of animals by purifying technical ammonium dihydrogen phosphate, characterized in that the feed grade ammonium phosphate is treated with water in an amount of 100 to 500 weight percent based on the original feed of ammonium technical phosphate at 60 ° C to boiling point, the resulting suspension or the liquid phase of the suspension is optionally oxidized with an oxidizing agent and / or hydrogen peroxide in an amount of 0.03 to 6% by weight of the active material based on the weight of the starting technical feedstock. %, in an amount of 0.03 wt.% iron to 6 wt.% iron relative to the feedstock of the technical feedstock, preferably an aqueous ferric chloride solution, then an aluminum salt in an amount of 15 to 150 wt. the sodium compound, preferably the phosphate and / or the sulfate and / or the sodium hydroxide, the precipitated sludge is separated and the filtrate is concentrated or diluted as necessary.