Solvay Fluor Und Derivate Gmbh

Other

Solvay Sa

Heinz-Joachim Belt

Werner Rudolph

Ruediger Sander

Michael Pittroff

Thomas Schwarze

Alfred Borinski

Hans-Walter Swidersky

Alfred Ottmann

Matthias Rieland

Thomas Born

Dirk Seffer

Klaus Baeumert

Pierre Barth&eacute;lemy

Hans-Peter Wickel

Reiner Distel

Steve Dobson

Jürgen Bosse

A flux based on alkali fluoroaluminate is described which is highly suitable for dry application ('dry fluxing'). This is a flux which is free of fine-grained fraction, which is defined by a range of grain-size distribution.

Brazing flux for dry application

Sulfuryl fluoride and ovicidal gases have been found to exert a synergistic action on insect eggs, so it is possible to fumigate under sublethal conditions relative to the ovicide, and the dose of ovicidal gas can be reduced e.g. to sublethal concentrations.

Synergistic control of pests

A flux based on alkali fluoroaluminate is described which is highly suitable for dry application (&ldquo;dry fluxing&rdquo;). This is a flux which is free of fine-grained fraction, which is defined by a range of grain-size distribution.

Gas mixtures of SF and N which have been used as an insulating filler gas for underground cables can be separated by use of a membrane separation in order to recover the SF .

Isolation of SF6 from insulating gases in gas-insulated lines

A method for the recovery or separation of sulfur oxyfluorides from gas mixtures, in which the gas mixture passes through at least one adsorption stage or membrane stage containing or consisting of zeolites with a modulus >10. The sulfur oxyfluorides fixed to the adsorbent may be made available for use after desorption. The sulfur oxyfluorides enriched through the membrane can be re-used directly.

Method for recovering and/or separating sulfur oxyfluorides from gas mixtures

Gas mixtures of SF and N , which have been used, for example, as an insulating filler gas for underground cables, for insulating-gas window panes or as a filler gas for car tires and SF /air mixtures which have been used as a protective gas when casting magnesium can be separated if they are contacted with hydrophobic zeolites of a certain pore size as selective adsorption agent for sulfur hexafluoride. For a relatively high SF concentration, the mixture is preferably first subjected to a membrane separation process and the permeate is contacted with the adsorption agent. The invention also relates to an apparatus for carrying out the process. The process may also be used for separating SF from exhaust gases.

Separation of gases containing SF6

The production of a potassium fluoroaluminate having a low melting point, which can be used as a flux when soldering aluminum. The potassium fluoroaluminate is prepared in an aqueous medium from aluminum hydroxide, hydrogen fluoride and potassium hydroxide in a molar ratio of aluminum:fluorine:potassium of approximately 1:5:2. After drying at 80&deg; C. under vacuum, the resulting potassium fluoroaluminate has a differential scanning calorimetry melting point of about 548&deg; C.

Low-melting potassium fluoroaluminate

A flux which contains irreversibly dehydrated K,AlF,, for soldering light metal materials, in particular aluminum. The flux has the advantages of forming a very uniform flux coating on the workpiece or workpieces to be soldered and exhibiting outstanding flow of the solder. An appropriate soldering process, an aqueous flux suspension and preparation processes for the flux are also disclosed.

Flux suitable for soldering light metals such as aluminum

Process for preparing flux suitable for soldering light metals such as aluminum

Preparation of homogeneous gas mixtures with SF.sub.6

A method for aluminum brazing, in which the addition of a solder is no longer necessary. For this purpose a flux is used which contains 6 to 50 wt-% of potassium fluorosilicate and 50 to 94 wt-% of potassium fluoroaluminate. The flux can be used, for example, in the form of an aqueous suspension or paste.

Solderless aluminum brazing

The production of a potassium fluoroaluminate having a low melting point, which can be used as a flux when soldering aluminum. The potassium fluoroaluminate is prepared in an aqueous medium from aluminum hydroxide, hydrogen fluoride and potassium hydroxide in a molar ratio of aluminum:fluorine:potassium of approximately 1:5:2. After drying at 80.degree. C. under vacuum, the resulting potassium fluoroaluminate has a differential scanning calorimetry melting point of about 548.degree. C.

A flux which contains irreversibly dehydrated K.sub.2 AlF.sub.5, for soldering light metal materials, in particular aluminum. The flux has the advantages of forming a very uniform flux coating on the workpiece or workpieces to be soldered and exhibiting outstanding flow of the solder. An appropriate soldering process, an aqueous flux suspension and preparation processes for the flux are also disclosed.

A method for preparing lithium hexafluorophosphate, which is useful as an electrolyte in primary and secondary cells, involves combining and cooling phosphorus pentachloride and lithium fluoride, and then adding hydrogen fluoride. Using this method, which is simple to perform, a good yield of the product can be obtained.

Method of preparing LiPF.sub.6

Metal structures, e.g. coolers or heat exchangers, can be produced by placing together metal components coated with solder, dipping them into a slurry of a flux, and soldering them by heating. Alternatively, components coated with solder can also be coated with flux, then placed together to form the metal structure and soldered by heating. In this case, however, the flux must be applied so as to adhere securely, and to this end in the prior art the flux has been 'glued on' to the metal surface by organic or other binders, which when burned out during the soldering process can produce undesirable exhaust gases or emissions. The present invention discloses a metal component which is provided with a sintered flux coating which adheres without binder. The coating can optionally also contain solder metal or other auxiliaries dispersed therein. The coating is applied, for example, by contacting the metal component with a binder-free slurry of the flux or dry coating the metal component electrostatically, and then heating the coated component while avoiding melting of the flux, so that an adherent sintered flux coating is formed on the metal component. The use of these coated metal components for the production of soldered metal structures and metal structures obtained using such components are also described. Potassium fluoroaluminate flux is particularly advantageously used.

Growing community of inventors

Burgwedel, Germany

Heinz-Joachim Belt