Process for the removal of iodine and organic iodine compounds from gases and vapours, and sorption agents whch are impregnated with metal salts for carrying out the removal process

Claim 2

A METAL SALT-IMPREGNATED SORPTION AGENT FOR A MEMBER SELECTED FROM THE GROUP CONSISTING OF IODINE AND ORGANIC IODINE COMPOUNDS WHICH HAVE A LOW NUMBER OF CARBON ATOMS, COMPRISING PARTICLES IN A FORM SELECTED FROM THE GROUP CONSISTING OF SPHERES AND GRANULES HAVING A DIAMETER OF LENGTH OF A FEW MILLIMETERS; A VOLUME OF POROSITY OF 50 TO 80%; A SPECIFIC SURFACE OF 70 TO 250 M2/G ACCORDING TO BET; A PROPORTION BY VOLUME OF PORES HAVING DIAMETERS OF LESS THAN 100 ANGSTROM UNITS OF AT LEAST 10%; A PROPORTION BY VOLUME OF PORES HAVING A DIAMETER OF MORE THAN 1000 ANGSTROM UNITS OF AT LEAST 5%; AND AN AMORPHOUS SILICIC ACID CONTENT OF AT LEAST 92% BY WEIGHT, BASED ON THE WEIGHT OF THE MATERIAL EXCLUSIVE OF THE METAL SALT, THE METAL SALT BEING PRESENT IN AN AMOUNT OF ABOUT 4 TO 18% BY WEIGHT OF METAL BASED ON THE WEIGHT OF THE BALANCE OF THE SORPTION AGENT, THE METAL OF SAID SALT BEING REACTIVE WITH IODINE.

Claim 3

A metal salt-impregnated sorption agent as claimed in claim 1, with silver nitrate as the impregnating material.

Claim 4

A metal salt-impregnated sorption agent as claimed in claim 2 further including a few percent of at least one member selected from the group consisting of aluminum oxide and an alkaline earth metal oxide.

Claim 5

In the removal of iodine or an iodine-containing organic compound from a gas wherein the iodine or iodine-containing compound is passed through a layer of porous particles of a sorption agent to remove said iodine from said gas, the improvement which comprises employing as said sorption agent particles of amorphous silicic acid impregnated with the salt of a metal reactive with iodine, said sorption agent having a lOw water adsorption and being resistant to hot steam and acid vapors, said particles being spherical in form, having a diameter of a few millimeters, a volume porosity of 50 to 80%, a specific surface of 70 to 250 m2/g according to BET, a proportion by volume of pores having diameters of less than 100 Angstrom units of at least 10%, a proportion by volume of pores having a diameter of more than 1000 Angstron units of at least 5%, and an amorphous silicic acid content of at least 92% by weight, based on the weight of the material exclusive of the metal salt, the metal salt being present in an amount of about 4 to 18% by weight of metal based on the weight of the balance of the sorption agent.

Claim 6

In the removal of iodine or an iodine-containing organic compound from a gas wherein the iodine or iodine-containing compound is passed through a layer of porous particles of a sorption agent to remove said iodine from said gas, the improvement which comprises employing as said sorption agent particles of amorphous silicic acid impregnated with the salt of a metal reactive with iodine, said sorption agent having a lOw water adsorption and being resistant to hot steam and acid vapors, said particles being spherical in form, having a diameter of a few millimeters, a volume porosity of 50 to 80%, a specific surface of 70 to 250 m2/g according to BET, a proportion by volume of pores having diameters of less than 100 Angstrom units of at least 10%, a proportion by volume of pores having a diameter of more than 1000 Angstron units of at least 5%, and an amorphous silicic acid content of at least 92% by weight, based on the weight of the material exclusive of the metal salt, the metal salt being present in an amount of about 4 to 18% by weight of metal based on the weight of the balance of the sorption agent.

Claim 7

A process according to claim 4, wherein the salt is a silver salt.

Claim 8

A process according to claim 5, wherein the salt is silver nitrate.

Claim 9

A process according to claim 6, wherein the sorption agent contains silver nitrate in an amount of about 4 to 18% by weight expressed as silver based on the weight of the balance of the sorption agent.

Claim 10

A process according to claim 7, wherein the sorption agent further contains a few percent of at least one member selected from the group consisting of aluminum oxide and an alkaline earth metal oxide.