JPS6011214A - Manufacture of alkaline metal phosphate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of alkali metal phosphates from naturally occurring phosphorus processes.

In the present invention, phosphorus is calcined with an alkali metal carbonate to form an alkali metal phosphate Z, and then leached from the calcined product under conditions that produce a relatively concentrated solution. include.

The composition of naturally occurring phosphorus compounds varies depending on the source. Certain rocks, such as Florida
)! J. ash is mostly calcium phosphate, while other rocks, such as balundite, are mostly iron and/or alkali metal phosphates. Christmas Island (Ch.
ristmas Tsland) C grade is a complex mixture of calcium, aluminum and iron phosphates. The relative proportions of calcium phosphate, iron phosphate, aluminum phosphate, and other components in rocks of different sources are subject to wide variation, as is well known to those skilled in the art.

The method of the present invention is varied according to the composition of the raw material in order to process different types of rock and obtain optimal results, as shown below.

In general terms, the present invention is characterized in that calcium, iron and aluminum phosphate-containing materials are calcined with alkali metal carbonates and then leached to produce alkali metal orthophosphates. A method for producing alkali metal phosphates from materials containing iron and aluminum phosphates is provided.

In a preferred embodiment of the present invention, the calcium phosphate is mostly calcined with an alkali metal carbonate at a temperature range ranging from 800°C to 1300°C. The resulting calcined product is cooled and leached with water containing alkali metal carbonates and bubbling carbon dioxide,
A solution of alkali metal orthophosphate and a calcium carbonate residue 7 are obtained.

The simplified chemical reaction below is considered to represent the process, where el is an alkali metal such as sodium or potassium.

Ca3(PO4)2+2Ak2CO3→2AkCaPO
4+C! ao+co22 AkC! aPO4+CaO
+ 2 Ak 2 Co 3 + Co 2 → 2 A
k3PO4+3CaCO3In a second mode of the invention, the same reaction is carried out, but with oxides of iron and/or aluminum mixed with alkali metal carbonates,
Speed up your reaction.

In a third mode of the invention, phosphorus processes such as balundite, which are predominantly iron and/or aluminum phosphates, are calcined with alkali metal carbonates at temperatures ranging from 800°C to 1600°C. do. The resulting calcined product is leached with water to form a solution of alkali metal orthophosphates and aluminates and a residue of iron hydroxide. The solution is cooled to crystallize the alkali metal orthophosphate.

The remaining solution can be further processed to recover aluminum trihydrate and alkali.

For simplification, the chemical reaction below is considered to be representative of 8W, and in the formula, Ak is an alkali metal such as sodium or potassium? show.

2FePO4+5Ak2CO3→2Ak3PO4+2A
kFe○2+3CO32AkFe02+4H20→2F
e(OH)3+2AkoH2AIPO4+6Ak2CO
3→5Ak3P04+2AkA10s++5CO2Ak
A102+2H20-+ Al(OH)3+Na0)T
Or 2AkA102+ CO□+3H2,○-+2*1(O
H) 3 + AkCO3 In a fourth mode of the invention, a phosphorus process containing calcium, iron and aluminum phosphates is calcined with an alkali metal carbonate in a temperature range ranging from 800°C to 1600°C. What fired products can be obtained? In the presence of alkali metal carbonates and carbon dioxide,
Leach with water. The resulting solution is separated from the solid residue to form an alkali metal orthophosphate and carbonate solution 7.

The remaining solution can be cooled to crystallize the alkali metal orthophosphate from the leaching solution and further processed to recover the alkali metal carbonate.

The simplified chemical reactions shown for the first and third methods of the present invention are believed to be representative of the process.

In a fifth mode of the invention, phosphorus treatment containing calcium, iron and aluminum phosphates is leached with alkali metal hydroxides and carbonates to produce iron and aluminum as orthophosphates. Phosphate accompanying aluminum is collected as trihydrate. The residue, essentially iron hydroxide and calcium phosphate, is then melted together with the alkali metal carbonate and further phosphate is recovered in the manner outlined in the first mode of the invention.

In the sixth method of the present invention, a phosphorus method containing mostly aluminum and iron phosphates is heated at a temperature of 800°C to 1600°C.
Calcinate with sodium and potassium carbonate at temperatures up to This is then leached with a heat source to form a solution of alkali metal orthophosphate and alkali metal aluminate. The solution is separated from the solid residue and then cooled.
Crystallize the alkali metal orthophosphate. This is then carbonated with carbon dioxide to precipitate aluminum trihydrate. The remaining solution, which is essentially alkali metal carbonate, is then evaporated to recover the carbonate, which is recycled to the calcination process.

The process may be illustrated by the representative reactions below.

2AIPO4+5Ak2CO3→5Ak3PO4+ 2
AICA102 + 5CO22FePO4+2A)C
2CO3→ 3Ak3PO4+2AkFe○2+6C○
22AkFe○2+4H20-+ 2Fe(OH)3+
2AkoH2AkA102+C○2+6H20→ 2A
l(OH)3+Ak2C'032AkOI(+CO2
→ A1□CO3+H20 Advantages There are two published methods for directly producing alkali metal orthophosphates from naturally occurring phosphorus, namely (1) melting calcium phosphate with alkali metal carbonate, followed by water treatment. leaching, e.g. C.R.-
fftsuku・rit:+ −(C,R,McCullough
h), U.S. Patent No. 2,220,790 FJA, m.
November 6, 1946.

(2) Iron and aluminum phosphates are leached in aqueous solutions of alkali metals, such as Rotpaum (Rot).
Hbaum) and Reeve, New Sealant Journal of Science (NewZeal)
and Journal of 5science)
, Volume 11, Issue 4, December 1968.

In the first method, unless a very dilute solution is used, the alkali metal phosphate reverts to an insoluble form. This reversion is probably due to the formation of calcium hydroxide during leaching, which then reacts in solution to form calcium phosphate, e.g. Ca3(po,)2+Na2co3-+ 2NaCaP
○4+CaO+C○2NaCaPO4+Na2CO3-
+ Na3PO4+CaC03C+aCO3CaO+C
O2 CaO + H20Ca(OR)2 6Ca(OR) 2 + 2Na ,, po4-+ 6
NaOH'+ Ca3 (PO4) 2 In order to obtain soluble phosphates in satisfactory yields by the Mack Crow process, very dilute and uneconomical solutions have to be used. The method of the present invention leaches in the presence of carbon dioxide, thus ensuring that the calcium is in a non-reactive calcium carbonate form during leaching.

In the case of complex calcium-iron-aluminum phosphates, such as Christmas Island C-grade rocks, Mini's method eliminates the direct entrainment of iron and aluminum without solubilizing the accompanying phosphorus with alkaline leaching. teeth,
For example, 50% to 60% of the total phosphorus is solubilized. In the method of the present invention, 9 of the total phosphorus in such rocks is
Be able to collect more than 0%.

EXAMPLES The invention is further illustrated in the following non-limiting examples.

Example 1 Floridarin Hoji Powder 100.9v Sodium Carbonate 1
60g and baked at 1200°C for 2 hours.

The sintered body was cooled, ground and leached with a 1501/-13 solution of sodium carbonate bicarbonate at 75°C. The leaching solution was flushed with carbon dioxide '12tlvI to ensure an excess of carbonate ions throughout.

After leaching for 120 minutes, the undissolved solids were separated from the solution, washed and dissolved. When the solution was cooled to 52° C., most of the phosphate originally present in the rock crystallized out in the form of mixed crystals of hydrated disodium orthophosphate and hydrated trisodium orthophosphate.

The remaining sodium carbonate bicarbonate solution was recycled to the freshly produced sinter leaching. By these methods, 92% of the phosphate in the original rock was collected as sodium orthophosphate.

Example 2 Except that aluminum trihydrate El''2 was added to the phosphorus method and then baked at 1000°C for 1-1/2 hours.
The experiment of Example 1 was repeated. Subsequent leaching yielded 94% of the phosphate originally present in the rock as sodium orthophosphate.

Example 6 Christmas Island C-grade rock was crushed, mixed with 150 g of potassium carbonate, and calcined at 950"C for 6 hours. The resulting sintered body was cooled, crushed, and hydrogen carbonated. 25 of potassium carbonate containing some potassium
Leaching at 70°C with 0g/43 solution. Carbon dioxide was passed through the leaching solution during leaching to ensure that bicarbonate ions were present at all times.

When the solution was separated from the insoluble solids and cooled to 66°C, most of the phosphate present in the original rock crystallized out as potassium orthophosphate.

The remaining solution was recycled for leaching a new batch of sintered bodies. Excess potassium carbonate bicarbonate formed in the leach solution, so a portion of the solution was evaporated and used to replace a portion of the potassium carbonate charge used in sintering.

According to these examples, in the present invention, more than 90% of the phosphate in the initial rock could be collected in the form of potassium phosphate.

Example 4 Residue 1'00 g of Christmas Island C-grade rock obtained by hydroxide alkalization was mixed with 150 g of 7R sodium carbonate and calcined at 1150° C. for 2 hours.

The resulting sintered body was then leached at 65°C with a sodium carbonate solution in the presence of carbon dioxide. The insoluble solids were separated from the solution and the solution was then cooled to 25°C to obtain crystals of sodium orthophosphate.

The remaining solution of IJium carbonate was recycled to extract the next batch of hydroxide alkalized extraction residue.

By combining hydroxide alkalinization extraction, carbonate melting and carbonate extraction in the presence of carbon dioxide, the present invention extracts 90% of the aluminum and 96% of the phosphates in the initial rock. be able to.

Example 5 100 g of naturally occurring balundite, predominantly iron and aluminum phosphates and containing less than 6% calcium, were mixed with 160 g of sodium carbonate and
It was baked at 000°C for 2 hours. The obtained sintered body is crushed,
It was then leached with a weak sodium aluminate hydroxide solution for 60 minutes at 70°C.

Separate the insoluble solids from the solution and remove the clear solution for 20 minutes.
It was cooled to ℃ and sodium orthophosphate Z was crystallized.

Aluminum trihydrate was then seeded into the solution containing sodium aluminate, diluted with water and measured as Na2O, and the sodium concentration was 1. ．．
A solution containing 120 g per 13 was prepared. The suspension was then gently stirred for 24 hours to decompose the sodium aluminate into sodium hydroxide and aluminum hydroxide. Aluminum trihydrate (hydroxide) IJ
and undecomposed sodium aluminate, and the remaining solution was recycled for further extraction of the sinter.

By the above method, the present invention was able to extract 90% of the aluminum and 92% of the phosphate in the initial rock.

Example 6 Balandite ioo,! iI”r potassium carbonate 150g
The resulting sintered body was leached with a weak potassium carbonate solution at 0°C to separate the undissolved residue from the solution.

The solution was cooled to 30°0, and potassium orthophosphate was separated from the remaining solution of potassium aluminate containing some potassium phosphate and potassium carbonate.

The remaining solution was then carbonated with carbon dioxide to precipitate aluminum trihydrate. Aluminum trihydrate 7 was separated, and the solution was further cooled to 20°C.
Potassium carbonate was crystallized and recovered. The remaining dilute solution of potassium carbonate was recycled into the leaching of a new patch of sintered body. The recovered potassium carbonate crystals were used to replace a portion of the potassium carbonate when sintering another batch of balundite.

Application for provisional patent in Australia, specification PF9977 filed on June 24, 1983, July 1, 1986
The disclosures of PGO No. 279, filed on September 4, 1986, and PGl No. 294, filed on September 7, 1986, are hereby incorporated by reference.

Agent Hajime Asamura

Claims (1)

[Claims] (11) characterized in that a material containing phosphates of calcium, iron and aluminum is calcined with an alkali metal carbonate and then leached to produce an alkali metal orthophosphate. , a method for producing an alkali metal phosphate from a substance containing calcium, iron and aluminum. (2) The above-mentioned method characterized in that the substance containing calcium, iron and aluminum is naturally occurring phosphate. The method described in item (1). (3) Naturally occurring phosphate is mostly calcium phosphate, and is characterized by being leached in the presence of alkali metal carbonates and carbon dioxide. The above (2)
). (4) The method according to item (3) above, characterized in that the leaching solution is cooled to crystallize and collect the soluble alkali metal orthophosphate. (5) The method according to item (4) above, characterized in that the remaining alkali metal carbonate is recycled for leaching and calcination. (6) Naturally occurring phosphate contains a small proportion of calcium phosphates and a large proportion of iron and aluminum phosphates, and post-calcination leaching is carried out without the addition of carbon dioxide Y% The method according to the above item (2), wherein the method is made into mold. (7) The method according to item (4) above, characterized in that the leaching solution is cooled to crystallize and separate the alkali metal phosphate, and this is removed and the remaining solution remains. . (8) extracting aluminum trihydrate from the remaining solution by adding carbon dioxide;
The method according to item (5) above. (9) Calcium, iron and aluminum phosphates are present in significant proportions in the rock, and the rock is first leached with alkali metal hydroxides and carbonates to form aluminum trihydrate and alkali metal phosphates. A salt-containing solution is produced, the aluminum trihydrate and alkali metal phosphate are extracted from the solution, and the remaining solid is calcined with an alkali metal carbonate. 4. The method according to item (2) above, characterized in that phosphate therein is collected by any of the methods up to item (5).