Method of recovering fluorine from carbonaceous waste material
AssigneeElkem-Spigerverket A/S
InventorErik Qvale Dahl
Life of this patent
Estimating the term…
Abstract
Particles of solid carbonaceous waste material which contain fluorine are suspended in a stream of gas consisting of a mixture of steam and air to establish a fluidized bed in a retort. The particles are heated to a temperature of not less than 1000.degree. C to cause pyrohydrolysis and the recovery of fluorine as gaseous hydrogen fluoride at a very efficient rate.
Claims7
A continuous method of recovering fluorine as hydrogen fluoride from particles of fluorine-containing solid carbonaceous material by pyrohydrolysis which comprises:
- a. a stream of gas comprising from 45to 50% steam;
- b. continuously feeding solid carbonaceous material of less than about 10 millimeters in size onto the said stream of gas;
- c. forming a fluidized bed by having said carbonaceous material suspended in said stream of gas;
- d. maintaining a temperature of at least above 1100.degree. C. in said fluidized bed for a sufficient time whereby said carbonaceous material is pyrohydrolyzed and evolves gaseous hydrogen fluoride;
- and
- e. collecting said evolved hydrogen fluoride whereby the recovery of fluorine from said carbonaceous material by said method is from 88 to 98% of the fluorine contained in said carbonaceous material and whereby the efficiency of said method expressed as a ratio of kilograms of steam used per kilogram of fluorine recovered is from 13 to 15 .
A continuous method of recovering fluorine as hydrogen fluoride from particles of fluorine-containing solid carbonaceous material by pyrohydrolysis which comprises:
- a. a stream of gas comprising from 45 to 60% steam;
- b. continuously feeding solid carbonaceous material of less than about 10 millimeters in size onto the said stream of gas;
- c. forming a fluidized bed by having said carbonaceous material suspended in said stream of gas;
- d. maintaining a temperature of at least above 1100.degree. C. in said fluidized bed for a sufficient time whereby said carbonaceous material is pyrohydrolyzed and evolves gaseous hydrogen fluoride;
- and
- e. collecting said evolved hydrogen fluoride whereby the recovery of fluorine from said carbonaceous material by said method is from 84 to 98% of the fluorine contained in said carbonaceous material and whereby the efficiency of said method expressed as a ratio of kilograms of steam used per kilogram of fluorine recovered is from 13 to 18.
Dependencies are inferred from the claim text.