CN1107661A

CN1107661A - Catalytic technology for processing calcium hydrogen phosphate as feed

Info

Publication number: CN1107661A
Application number: CN94101967A
Authority: CN
Inventors: 林恒兴
Original assignee: YUNNAN FINE CHEMICAL CO
Current assignee: YUNNAN FINE CHEMICAL CO
Priority date: 1994-03-01
Filing date: 1994-03-01
Publication date: 1995-09-06

Abstract

The calcium bi-phosphate as feed additive is prepared through such technological steps as decomposition reaction of powdered phosphorus ore, water and sulfuric acid under existance of catalyst to obtain calcium dihydrogen phosphate, calcium sulfate and fluride, adding sulfide for regulating pH value to 1-2.5, filtering, water washing, regulating pH value of filtrate to 2.5-3.2, removing fluorine, filtering to obtain pure solution of calcium dihydrogen phosphate, neutralizing and separation of mother liquid that may be reused.

Description

Catalytic technology for processing calcium hydrogen phosphate as feed

The present invention relates to a kind of method for production of phosphate salt, especially the preparation technology of calcium hydrophosphate fodder.

Calcium hydrophosphate fodder is to replenish animal phosphorus and calcium two grow greatly, the source of metabolic important element, and the calcium hydrophosphate fodder preparation method of present public use has three kinds: a, thermal phosphoric acid neutralisation; B, wet phosphoric acid purifying neutralisation; C, normal superphosphate extracting and purifying neutralisation.Though thermal phosphoric acid neutralisation production technique is simple, the price of thermal phosphoric acid has substantially exceeded the price of calcium hydrophosphate fodder, makes this method lose competitive capacity on the market; The wet phosphoric acid purifying neutralisation, need the sulfuric acid that consume that ground phosphate rock is decomposed into phosphoric acid more, the residue phosphogypsum that is discharged is more, is unfavorable for environment protection, because temperature of reaction is higher, be 80-110 ℃, serious to equipment corrosion, also need increase the fluorine device for absorbing tail gas, thereby facility investment is increased, cost increases, and the yield of phosphorus only is about 70%; The normal superphosphate method is one of method of comprehensive utilization of chemical fertilizer, though sulfuric acid consumption reduces, ground phosphate rock only decomposes to monocalcium phosphate, and the phosphorus rate of decomposition will reach more than 90%, and needs the curing time more than 7 days, the sad filter of residue phosphogypsum, and the yield of phosphorus also only reaches 60-70%.

Chinese patent application CN1048015A(application number 90100845) method of a kind of " low ratio acid wet method production calcium hydrophosphate fodder " is disclosed, it is characterized in that with low ratio sulfuric acid treating phosphorite stone, by leaching Rock Phosphate (72Min BPL), generate phosphoric acid and biphosphate calcium salt, adopt milk of lime to make one section quick defluorination of neutralization, carry out two sections neutralization precipitations with milk of lime again, adopt vibration fluidized drying calcium hydrophosphate fodder.The described method of this application belongs to the above-mentioned second class wet phosphoric acid purifying neutralisation.

Purpose of the present invention is intended to overcome the deficiencies in the prior art, provides a kind of catalysis method to prepare the novel process of calcium hydrophosphate fodder.

Catalytic technology for processing calcium hydrogen phosphate as feed of the present invention is made up of following steps:

(1), ground phosphate rock, extraction water, sulfuric acid are carried out decomposition reaction under catalyst action, generation monocalcium phosphate, calcium sulfate and fluorochemical, adding sulfide, transfer PH to 1-2.5, filter, filter residue is calcium sulfate, arsenic and beavy metal impurity, and washing back filter residue is abandoned it;

(2), the filtrate of (one) adjusts PH to 2.5-3.2, removes fluorine, filters, and obtains purified biphosphate calcium solution;

(3), neutralization (two) gained solution to PH be 5-7, separate mother liquor, make calcium hydrogen phosphate fodder, mother liquor can be recycled.

In technology of the present invention, earlier with P ₂O ₅Content is that the ground phosphate rock of 20-34% adds water (extraction water), is made into ore pulp, adds the catalyzer of 0.3-3% weight, adds the sulfuric acid of 50-80% weight again, carries out decomposition reaction under normal temperature, and reaction formula is as follows:

Here used sulfuric acid concentration is 20-98%, catalyzer is one or more the mixture in the salt of strong acid example hydrochloric acid, sulfonic acid, nitric acid, phenol sulfonic acid and basic metal or alkaline-earth metal such as sodium salt, sylvite, ammonium salt, the calcium salt, the carrying out time of decomposition reaction is 2-24 hour in step (), the phosphorus rate of decomposition reaches about 95%, adds cleaner Na in above-mentioned reactant ₂S, H ₂The S sulfides, add-on is the 0.01-0.05% of ground phosphate rock amount, remove impurity such as arsenic and heavy metal, add cleaner Paris white or milk of lime again and transfer PH to 1-2.5, remove by filter calcium sulfate, the sulfide of heavy metal and arsenic, the washing filter cake, extraction water and wash water consumption add up to 4-8 times of ground phosphate rock, add calcic thing such as Paris white or milk of lime again and transfer PH to 2.5-3.2, temperature 10-30 ℃, carry out the defluorination reaction, filtration or sedimentation (adopting polyacrylamide as sinking agent) obtain purified biphosphate calcium solution, adding content is that the milk of lime of 10-25% carries out neutralization reaction, and reaction formula is as follows:

To pH value be 5-7, separate mother liquor, obtain solid phosphoric acid hydrogen calcium.

Technology of the present invention is owing to added catalyzer; make the reaction of sulfuric acid decomposing rock phosphate with hydrogen can be at normal temperature; carry out under the normal pressure; and only decompose monocalcium phosphate; consume sulfuric acid 1/3 less; discharge waste residue 1/3 less; shorten the resolving time to a few hours; improve about phosphorus rate of decomposition to 95%, two sections neutralizations that this technology changes in the past are three sections neutralizations, make the phosphorus yield improve; and equipment corrosion slows down; also, deducted traditional fluorine device for absorbing tail gas, made facility investment significantly reduce because the fluorine exhaust emissions is less; and that the production cost of products obtained therefrom calcium hydrogen phosphate fodder reduces is about 30%, helps environment protection.

Embodiment:

In 10 cubes of reactors, add 3 cubes of entry, stir the adding vitriol oil (content 98%) 1 ton down, add 50 kilograms in catalyzer ammonium nitrate and contain P ₂O ₅1.5 tons in 32% ground phosphate rock reacted 4 hours down at 60 ℃, added 5 kilograms of 1% sodium sulphite liquid then, transferred PH to 2 with 20% milk of lime again, used vacuum filtration, and washed filter residues with 3 tons.Add Paris white in the filtrate and transfer PH to 3, vacuum filtration is with 0.5 ton of washing filter residue.Filtrate is neutralized to PH6 with 20% milk of lime again, centrifugation, wet product promptly got in 180 ℃ warm air drying with pneumatic drier and contains P 〉=16.0%, Ca 〉=21.0%, F≤0.18%, As≤0.003% in 30 seconds, 1 ton of heavy metal (in lead)≤0.002% calcium hydrogen phosphate fodder, and the phosphorus total recovery reaches 80%.

Claims

1, a kind of catalytic technology for processing calcium hydrogen phosphate as feed is characterized in that being made up of following steps:

(1), ground phosphate rock, extraction water, sulfuric acid are carried out decomposition reaction under catalyst action, generate monocalcium phosphate, calcium sulfate and fluorochemical, add sulfide, transfer PH to 1-2.5, filter, filter residue is calcium sulfate, arsenic and beavy metal impurity, and washing back filter residue is abandoned it;

2,, it is characterized in that described catalyzer is one or more a mixture of the salt of strong acid and basic metal or alkaline-earth metal according to the described technology of claim 1.

3,, it is characterized in that described catalyzer add-on is 0.3-3% according to the described technology of claim 1.

4,, it is characterized in that described sulfuric acid concentration is 20-98% according to the described technology of claim 1.

5,, it is characterized in that described vitriolic add-on is 50-80% according to the described technology of claim 1.

6,, it is characterized in that the carrying out time of decomposition reaction in the step () is 2-24 hour according to the described technology of claim 1.

7,, it is characterized in that middle extraction water of step () and wash water consumption add up to 4-8 times of ground phosphate rock according to the described technology of claim 1.