Treatment of pitches in carbon artifact manufacture
AssigneeExxon Research & Engineering Co.
InventorSydney H. Greenwood
Life of this patent
Estimating the term…
Abstract
Isotropic carbonaceous pitches are fluxed with an organic liquid thereby providing a fluid pitch which has substantially all of the quinoline insoluble material suspended in the pitch and which quinoline insoluble material is readily separable from the fluid pitch by filtration, centrifugation and the like. Thereafter the pitch is treated with an anti-solvent so as to precipitate at least a substantial portion of the pitch free of the quinoline insoluble solids.
Claims16
A process for treating carbonaceous graphitizable pitches comprising:
- adding an organic fluxing liquid to a carbonaceous graphitizable pitch to provide a fluid pitch containing insoluble solids suspended therein, said solids including substantially all the quinoline insoluble solids present in the pitch, said organic fluxing liquid being added in an amount sufficient to lower to viscosity of the pitch whereby the fluid pitch is capable of flowing through a 0.5 micron filter with suction filtration;
- separating said fluid pitch from said solids;
- treating said separated fluid pitch with an organic liquid to precipitate at least a substantial portion of said pitch;
- and,
- separating the precipitated pitch from said organic liquid whereby a pitch free of quinoline insoluble solids is obtained.
A process for treating a thermal or cracked residuum of a petroleum origin capable of being thermally converted to an optically anisotropic phase comprising:
- heating said residuum at temperatures in the range of from about 350.degree. C. to about 450.degree. C. at least until polarized light microscopic examination of samples of said heated residuum indicate the formation of optically anisotropic spherules therein;
- terminating said heating and adding an organic fluxing liquid to said heated residuum to provide a fluid pitch containing insoluble solids suspended therein, said solids including substantially all the quinoline insoluble solids present in said heated residuum;
- separating said solids from said fluid pitch;
- treating said separated fluid pitch with an organic solvent system having a solubility parameter at 25.degree. C. of between about 8.0 and about 9.5, said treating being at a temperature and with an amount of organic solvent system sufficient to provide a solvent insoluble fraction which is thermally convertible into a deformable pitch containing greater than 75% of an optically anisotropic phase;
- and,
- separating said solvent insoluble fraction from said solvent system.
In the process of preparing an isotropic carbonaceous graphitizable feedstock for carbon fiber production by extracting an isotropic carbonaceous pitch with an organic solvent system having a solubility parameter at 25.degree. C. of between about 8.0 and 9.5 to provide a solvent insoluble carbon fiber feedstock which is separated from said solvent system, the improvement comprising:
- first adding a fluxing liquid to said isotropic carbonaceous pitch to provide a fluid pitch having separable quinoline insoluble solids suspended therein, said fluxing liquid being added in an amount sufficient to lower the viscosity of the pitch so that the pitch is capable of flowing through a 0.5 micron filter with suction filtration;
- separating said quinoline insolubles from said fluid pitch and thereafter treating said fluid pitch with said organic solvent system to precipitate a solvent insoluble carbon fiber feedstock and separating said feedstock from said organic solvent system, whereby a feedstock eminently suitable for carbon fiber formation is obtained.
Dependencies are inferred from the claim text.