Recycling of flux material
AssigneeSolvay Fluor und Derivate GmbH
InventorsUlrich Seseke-Koyro, Thomas Born
Life of this patent
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Abstract
Flux residues from aluminium soldering fluxes composed of alkali metal metallates, especially fluoroaluminates of the alkali metals, in particular potassium and cesium, can be recycled by adding them to the reaction mixture used for the production of hydrogen fluoride from fluorspar and sulfuric acid or oleum. In this way the fluorine content of the flux residues becomes reusable, and the anhydrite which is produced can advantageously be used for conventional purposes.
Claims16
A method of recycling residue of an alkali metallate flux for soldering aluminum, said alkali metallate flux comprising at least one alkali metallate selected from the group consisting of alkali metal fluoroaluminates and alkali metal fluorozincates, said method comprising the steps of:
- admixing the flux residue with fluorspar;
- and
- reacting the admixed fluorspar and flux residue with sulfuric acid or oleum to produce hydrogen fluoride and anhydrite.
In the production of hydrogen fluoride by reacting sulfuric acid or oleum with fluorspar, the improvement comprising incorporating in the fluorspar prior to reaction with the sulfuric acid or oleum, a positive amount up to 2% by weight of a flux residue of an alkali metallate flux for soldering aluminum.
A composition of matter useful as a reactant in the production of hydrogen fluoride, said composition of matter comprising an admixture of fluorspar and a residue of an alkali metallate flux for soldering aluminum, said alkali metallate flux comprising at least one alkali metallate selected from the group consisting of alkali metal fluoroaluminates and alkali metal fluorozincates.
Dependencies are inferred from the claim text.