JP2002177769A - Method of forming resources from base material consisting essentially of aluminum phosphate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily recover a phosphate of an alkali metal or calcium phosphate from a base material consisting essentially of aluminum phosphate. SOLUTION: The phosphate of the alkali metal produced by adding silica or silicon dioxide powder and a carbonate or bicarbonate of the alkali metal or a hydroxide of the alkali metal into the base material consisting essentially of aluminum phosphate and heating at 800-1000 deg.C to prepare an adsorbent, pulverizing the adsorbent prepared in this way, adding water into the pulverized adsorbent and mixing is separated, concentrated to be crystallized and recovered and the residue is used as the adsorbent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recycling aluminum phosphate as a main component.

[0002]

2. Description of the Related Art Conventionally, as a method for recovering phosphorus from incinerated ash such as sewage sludge, there is a method in which an acid is added to these incinerated ash to elute phosphorus, and the eluted phosphoric acid is extracted with a solvent.
In addition, as a simple processing method, there is a method of separating and recovering phosphorus mainly by aluminum phosphate by adjusting the pH by adding an alkali. This recovered material contains iron phosphate, by-product calcium sulfate, and the like, in addition to aluminum phosphate.

[0003]

SUMMARY OF THE INVENTION pH to which alkali is added
According to the simple treatment method by adjustment, the phosphorus to be recovered is recovered with aluminum phosphate as a main component. However, due to the limited use of aluminum phosphate, it is necessary to convert it to another phosphate such as calcium phosphate or sodium phosphate.

Accordingly, an object of the present invention is to provide a method for recycling aluminum phosphate-based materials from which aluminum phosphate-based materials can be easily recovered from aluminum phosphate-based materials. Is to provide.

[0005]

According to the first aspect of the present invention,
Aluminum oxide and aluminum in various aluminum salts utilize zeolite by reacting with silicon dioxide and an alkali metal compound in a high temperature range. At this time, it is considered that phosphorus in the aluminum phosphate separates from the aluminum and reacts with the alkali metal compound to form a phosphate of the alkali metal. The phosphate is dissolved in water, concentrated and recovered by crystallization separation. Iron phosphate existing as an impurity is decomposed in the high-temperature range to become alkali metal phosphate and iron oxide.

That is, according to the first aspect of the present invention, a raw material containing aluminum phosphate as a main component is added with silica sand or silicon dioxide powder and a carbonate or bicarbonate of an alkali metal or a hydroxide of an alkali metal to 800 to 800%. Heating to a temperature range of 1000 ° C. to produce an adsorbent mainly composed of aluminum silicate, then pulverizing the adsorbent thus produced, then adding water to the pulverized adsorbent and mixing The phosphate of the alkali metal thus produced is separated, and the phosphate thus separated is concentrated and crystallized and recovered, and the residue is used as an adsorbent.

According to a second aspect of the present invention, a calcium salt or a magnesium salt is added to the solution at a pH of 9 or more to recover the alkali metal phosphate aqueous solution produced by the method of the first aspect of the invention without concentrating the solution. By reacting, phosphorus is precipitated and recovered as a phosphate or magnesium phosphate mainly composed of tertiary calcium phosphate.

[0008] That is, the present invention according to claim 2 is to add a silica sand or silicon dioxide powder and an alkali metal carbonate or bicarbonate or an alkali metal hydroxide to a raw material containing aluminum phosphate as a main component, to obtain a powder having a viscosity of 800 to 800 ppm. Heating to a temperature range of 1000 ° C. to produce an adsorbent mainly composed of aluminum silicate, then pulverizing the adsorbent thus produced, then adding water to the pulverized adsorbent and mixing The calcium phosphate or magnesium salt is added to the thus separated phosphate to precipitate calcium phosphate or magnesium phosphate, which is separated and recovered, and the residue is adsorbed. Is characterized by the following.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As a material containing aluminum phosphate as a main component, a material obtained by recovering phosphorus in an incinerated ash by an acid treatment or an alkali treatment, a phosphate ore containing aluminum phosphate as a main component, and the like can be considered.

[0010] Silica sand powder is added to a material mainly composed of aluminum phosphate, and an alkali metal carbonate, bicarbonate or hydroxide is added thereto and mixed well. The amount of the alkali metal carbonate or hydroxide to be added is a ratio required in the following chemical formula (1). As silica sand powder, 150 g is used to crush natural silica sand and increase reactivity.
Use a particle having a particle size equal to or smaller than a mesh, or synthesized amorphous silicon dioxide or the like.

[0011] _{AlPO 4 + Na · XSiO 2 ·} YH 2 O + Na 2 O 3 = NaAl · XSiO 2 · YH 2 O --- (1) where, in the above formula (1), X, Y indicates a coefficient.

Heating is performed at a temperature of 800 to 1000 ° C. for 1 to 2 hours, which is necessary for the chemical formula (1), for a time necessary for completing the reaction. At this temperature, the aluminum content in the aluminum phosphate reacts with the silica sand powder and the alkali metal to produce zeolite. The phosphorus in the aluminum phosphate reacts with the alkali metal salt or alkali metal hydroxide to produce a third or second alkali metal salt of phosphoric acid. The product heat-treated at this temperature is naturally cooled at room temperature, and then pulverized, further added with water, and stirred to dissolve the water-soluble phosphate.

The dissolved water-soluble phosphate is filtered off. The residue is further washed with water, neutralized and dried if necessary, and used as an adsorbent mainly composed of zeolite.

The solution in which the alkali metal phosphate is dissolved is concentrated to a saturated concentration of the phosphate, and then cooled to a temperature at which crystallization is possible, and the phosphate is separated and recovered. The wastewater is further evaporated to dryness, and the remaining alkali is reused.

FIG. 1 is a flow chart of the first embodiment of the present invention.
Shown in

In addition, a water-soluble calcium or magnesium salt powder or an aqueous solution is added to the aqueous alkali metal phosphate solution produced and eluted by the above-mentioned method, and the mixture is stirred and dissolved. In water having a pH of 9 or more, a phosphate of calcium or magnesium is formed. In the case of calcium, a phosphate mainly composed of calcium tertiary phosphate is produced by the following chemical formula (2). This tertiary calcium salt precipitates because it is hardly soluble in water. This precipitate is separated by filtration and collected. The third phosphate of an alkali metal is a strong alkali. However, as shown in the chemical formula (2), by generating calcium phosphate, most of the alkali is substantially consumed, and as a result, the pH drops to around 9. To go. The filtrate from which the calcium phosphate has been recovered is further subjected to a water treatment such as neutralization if necessary, and then discharged.

3CaX ₂ + 2Na ₃ PO ₄ = Ca ₃ (PO ₄ ) ₂ + 6NaX (2) In the above chemical formula (2), X represents an anion.

FIG. 2 is a flow chart according to the second aspect of the present invention.
Shown in

[0019]

The test was carried out using 20 g of commercially available aluminum phosphate. To this, 35 g of sodium carbonate and 10 g of amorphous silica sand (powder) were added, and sufficiently stirred and mixed. This was heated at 900 ° C. for 2 hours in an electric furnace.

After cooling to room temperature, the semi-molten sample was ground in a mortar, and 500 ml of water was added thereto, followed by stirring and dissolution. This is separated by filtration, and 500 ml of washing water is further added.
And washed to remove phosphoric acid, and the remaining powder mainly composed of zeolite was recovered. The combined filtrate and washings were concentrated by heating and evaporated to dryness to recover a mixture of tertiary or dibasic sodium phosphate.

Further, 20 g of commercially available aluminum phosphate, 10 g of amorphous silica sand (powder), and 35 g of sodium carbonate powder were heated to a temperature of 900 ° C., and the resulting tertiary sodium phosphate was dissolved in water in the same manner as described above. Then, 70 g of calcium sulfate hydrate crystals were added and dissolved by stirring. The initial pH was above 12, but gradually decreased with the formation of calcium phosphate. It was confirmed that most of the phosphorus was precipitated as calcium phosphate when the pH reached 9, and the precipitate was separated by filtration.

The yields of the zeolite-based adsorbent, sodium tertiary phosphate and calcium phosphate recovered by the above method were as shown in Table 1.
In addition, component analysis was performed on the recovered material using a fluorescent X-ray analyzer. Table 2 shows the results.

[0023]

[Table 1]

[0024]

[Table 2]

As a performance test of the produced zeolite, J
An adsorption performance test using methylene blue according to the activated carbon test method of IS-K1474 was performed. The results are shown in Table 1. As is clear from Table 1, sufficient adsorption capacity was observed.

[0026]

As described above, according to the present invention, calcium phosphate and alkali metal phosphate can be easily converted from a material containing aluminum phosphate as a main component by a simple treatment only by heating using an inexpensive material. Can be manufactured,
In addition, since phosphorus in aluminum phosphate can be converted to water-soluble only by heat treatment, it can be used as a fertilizer even with heat-treated material alone. Further, alkali is added at a high temperature of 800 ° C. or more for treatment. A useful effect such that decomposition and removal of harmful substances such as dioxin is possible.

[Brief description of the drawings]

FIG. 1 is a flowchart of the invention of claim 1;

FIG. 2 is a flowchart of the invention of claim 2;

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Susumu Kato 3690-1, Sakuracho, Yokkaichi-shi, Mie Prefecture Inside the Mie Prefectural Institute of Science and Technology Health and Environmental Research Institute (72) Inventor Seiji Iwasaki 3690-1, Sakuramachi, Yokkaichi-shi, Mie Pref. Inside the Health Promotion Center, Technology Promotion Center (72) Inventor Akira Yamashita 3690-1, Sakuramachi, Yokkaichi City, Mie Prefecture Inside the Health and Environment Research Center, Science and Technology Promotion Center, Mie Prefecture (72) Keisuke Nakahara 1-2-1, Marunouchi, Chiyoda-ku, Tokyo F-term (reference) in Nippon Kokan Co., Ltd. 4G066 AA13A AA22A AA43A AA47A AA50A AA61B BA01 FA03 FA22 FA34 FA38

Claims (2)

[Claims] A raw material containing aluminum phosphate as a main component is added with silica sand or silicon dioxide powder and an alkali metal carbonate or bicarbonate or an alkali metal hydroxide, and heated to a temperature range of 800 to 1000 ° C. To produce an adsorbent mainly composed of aluminum silicate, and then pulverize the adsorbent thus produced, and then add water to the pulverized adsorbent and mix to form an alkali metal phosphoric acid. A method for recovering from a material containing aluminum phosphate as a main component, wherein a salt is separated, and the phosphate separated in this way is concentrated and crystallized and recovered, and a residue is used as an adsorbent. 2. A material containing aluminum phosphate as a main component is added with silica sand or silicon dioxide powder and an alkali metal carbonate or bicarbonate or an alkali metal hydroxide, and heated to a temperature range of 800 to 1000 ° C. To produce an adsorbent mainly composed of aluminum silicate, and then pulverize the adsorbent thus produced, and then add water to the pulverized adsorbent and mix to form an alkali metal phosphoric acid. A salt is separated, and a calcium salt or a magnesium salt is added to the phosphate separated in this way to precipitate calcium phosphate or magnesium phosphate, and separated and recovered. How to recycle resources from materials.