Process for the preparation of heteropoly acid complex compounds of metaphosphoric metasilic acid, metaphosphoric acid and phosphorous pentoxide

Claim 2

The process of claim 2 including an additional heating step in which the product is decomposed to release HPO3 as a volatile product and SiP2O7 as a solid product and separately recovering said HPO3 and said SiP2O7.

Claim 3

The process of claim 3 which comprises, in addition, heating said SiP2O7 to between 575* and 800* C. and recovering the P2O5 sublimed from said SiP2O7.

Claim 4

The process of claim 1 wherein the silica starting material is a solid amorphous SiO2.

Claim 5

The process of claim 1 wherein the silica starting material is metasilicic acid.

Claim 6

A process for the production and recovery of oxygen containing compounds of phosphorous or silicon which comprises the steps of: a. adding a siliceous material selected from the group consisting of amorphous silica, metasilicic acid, disilicic acid and orthosilicic acid to a solution of orthophosphoric acid; b. heating the resulting product to a temperature below about 300* C. to dissolve said added material and forming solid heteropoly acid complexes; c. subsequently heating the solution obtained in (b) to a temperature of between about 300*-575* C. to effect condensation and to form other heteropoly acid complexes with P2O5 adducts; d. further heating at a temperature of about 575*-800* C. to release volatile metaphosphoric acid and leave a residue of silicon pyrophosphate; e. heating at a temperature of about 800*-1,000* C. to decompose said silicon pyrophosphate to form phosphorous pentoxide and silicon dioxide.

Claim 7

The process of claim 7 wherein the relative proportions of orthophosphoric acid and siliceous material are between 2:1 and 8:1.

Claim 8

The process of claim 7 wherein said solid heteropoly complex acid has the formula H2SiO3.XHPO3 where X is less than about 8.

Claim 9

The process of claim 7 wherein said other heteropoly acid complex with P2O5 adduct is represented by the general formula H2SiO3.XP2O5.YHPO3 wherein X and Y are each below 10.

Claim 10

The process of claim 7 wherein said HPO3 and said SiP2O7 are recovered separately.

Claim 11

The process of claim 7 wherein the silica starting material is a solid amorphous SiO2.

Claim 12

The process of claim 7 wherein the silica starting material is metasilicic acid.

Claim 13

A process for the production and recovery of oxygen-containing compounds of phosphorus or silicon from orthophosphoric acid and amorphous silica or its hydrates as starting materials which comprises mixing siliceous material selected from the group consisting of amorphous silica, metasilicic acid, disilicic acid and orthosilicic acid in an aqueous solution of orthophosphoric acid in a mol ratio of H3PO4 to siliceous material of 2:1 to 8:1 and thereafter heating the resulting mixture to produce intermediate heteropoly complex acid compounds which upon further heating within selected temperature ranges between about 275* C. to about 1,000* C. are capable of producing specified oxygen-containing compounds of phosphorus and silicon.

Claim 14

A process according to claim 14 wherein said mol ratio is 2: 1-6:1 and said intermediate compounds are heated at 275*-295* C. to produce a dry, granular product suitable for use as heat-regeneratable desiccant and dehydrating agent.

Claim 15

A process according to claim 14 wherein said mol ratio is 6: 1 to 8:1 and said intermediate heteropoly complex acid compounds are heated to 475*-525* C. to produce a product suitable as a source for metaphosphoric acid and phosphate phosphorous in water soluble and hydrolyzable form.

Claim 16

A process according to claim 14 wherein said mol ratio is 4: 1 to 8:1, and said intermediate heteropoly complex acid compounds are first heated to 475*-500* C. and the resultant products thereafter further heated to 600* to 800* C. to liberate volatilized metaphosphoric acid.

Claim 17

A process according to claim 14 wherein said mol ratio is about 2:1, and said intermediate heteropoly complex acid compounds are first heated to about 500* C. to remove all waTer and thereafter further heating to 885* to 1,000* C. to effect sublimation of P2O5.

Claim 18

A process according to claim 14 wherein said mol ratio is 2: 1 to 6:1 and said mixture is heated to either 300* or 500* C. to obtain a heteropoly acid complex of strongly acidic character and possessing strong dehydration capacity.

Claim 19

Dry, granular products suitable for use as heat-regeneratable desiccants and as dehydration reagents prepared in accordance with the process of claim 15.

Claim 20

Dry, granular products suitable for use as source materials of metaphosphoric acid and phosphate phosphorus in water soluble and hydrolyzable form such as for use in high equivalent P2O5 content agricultural chemicals prepared in accordance with the process of claim 23.

Claim 21

Dry, granular products suitable for use as source materials for the production of metaphosphoric acid prepared in accordance with the process of claim 24.

Claim 22

Dry, granular products suitable for preparing sublimed P2O5 prepared in accordance with the process of claim 18.

Claim 23

Dry,036524023 granular products suitable for use as source materials of strongly ionizable hydrogen ions prepared in accordance with the process of claim 19.