Method of treating spent potliner material from aluminum reduction cells
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
C22B-021/00
C01C-003/00
C01B-007/00
C01B-009/00
출원번호
US-0977435
(1997-11-24)
발명자
/ 주소
Barnett Robert J.
Mezner Michael B.
출원인 / 주소
Goldendale Aluminum Company
대리인 / 주소
Alexander
인용정보
피인용 횟수 :
20인용 특허 :
6
초록▼
A process for treating spent potliner material from aluminum reduction cells and recovering useful products. In the process, spent potliner material is introduced into an acid digester containing, for example, sulfuric acid. A gas component is produced which includes hydrogen fluoride and hydrogen c
A process for treating spent potliner material from aluminum reduction cells and recovering useful products. In the process, spent potliner material is introduced into an acid digester containing, for example, sulfuric acid. A gas component is produced which includes hydrogen fluoride and hydrogen cyanide. A slurry component is produced which includes carbon, silica, alumina, sodium compounds such as sodium sulfate, aluminum compounds such as aluminum sulfate, iron compounds such as iron sulfate, magnesium and calcium compounds such as magnesium and calcium sulfate. The slurry component remains in the digester after the gas component is removed. The gas component is recovered and heated an effective amount to convert or decompose the hydrogen cyanide to a remaining gas component including CO.sub.2, H.sub.2 O, and nitrogen oxides, as well as HF gas. The remaining gas component is directed through a water scrubber in which the HF gas is converted to liquid hydrofluoric acid. The hydrofluoric acid is then admixed with alumina trihydrate to form aluminum fluoride and water. Valuable refractory materials and salts are recovered also.
대표청구항▼
[ What is claimed is:] [1.] A method of treating spent potliner material from aluminum reduction cells, which spent potliner material includes at least one material selected from the group consisting of fluoride compositions, cyanide compositions, iron compositions, calcium compositions, magnesium c
[ What is claimed is:] [1.] A method of treating spent potliner material from aluminum reduction cells, which spent potliner material includes at least one material selected from the group consisting of fluoride compositions, cyanide compositions, iron compositions, calcium compositions, magnesium compositions, alumina, carbon, silica and sodium sulfate, said method comprising the steps of:(a) introducing said spent potliner material to an acid digester to produce a first gas component which includes at least one material selected from the group consisting of hydrogen fluoride gas and hydrogen cyanide gas, and a slurry component including at least one material selected from the group consisting of carbon, silica, alumina, sodium sulfate, iron sulfate, calcium sulfate and magnesium sulfate;(b) recovering said gas component from said digester and heating it to a temperature sufficient to decompose hydrogen cyanide which has been produced, and thereby produce a second gas component which is substantially free of cyanide and includes at least one offgas selected from the group consisting of CO.sub.2, H.sub.2 O, nitrogen and said HF gas;(c) combining said second gas component with water in a water scrubber to form hydrofluoric acid from HF included in the second gas component;(d) admixing said hydrofluoric acid with alumina trihydrate to form aluminum fluoride;(e) rinsing said slurry component with water and separating a first solid fraction including at least one of the group consisting of carbon, alumina and silica from a first liquid fraction;(f) adjusting said first liquid fraction to a first basic pH effective in forming an aluminate in solution while precipitating impurities containing elements selected from the group consisting of Ca, Fe and Mg and then filtering the impurities from liquid in the first liquid fraction to provide a filtered liquid fraction;(g) adjusting the filtered liquid fraction to a second pH effective in forming and precipitating alumina trihydrate from the filtered liquid;(h) admixing said first solid fraction with an alumina/silica mix to provide a mixture; and(i) subjecting said mixture to an elevated temperature in an oxygen-rich atmosphere to oxidize said carbon and vitrify said alumina and silica into refractory material.
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이 특허에 인용된 특허 (6)
Keller Rudolph (4221 Roundtop Rd. Export PA 15632) Cochran C. Norman (22 Oak Glenn Dr. Oakmont PA 15139) Stofesky David B. (611 Mayville Ave. Pittsburgh PA 15226), Decomposition of cyanide in electrolytic cell lining.
Grolman Robert J. (Chicoutimi CAX) Holywell George C. (Kingston CAX) Kimmerle Frank M. (Jonquiere CAX) Turcotte Gilles R. (Chicoutimi CAX), Recycling of spent pot linings.
Kidd Ian Lewis,AUX ; Rodda Darren Paul,AUX ; Wellwood Grant Ashley,AUX, Treatment of solid material containing fluoride and sodium including mixing with caustic liquor and lime.
Boudreault, Richard; Primeau, Denis; Labrecque-Gilbert, Marie-Maxime; Dumont, Hubert, Processes for preparing alumina and magnesium chloride by HCl leaching of various materials.
Boudreault, Richard; Fournier, Joël; Primeau, Denis; Labrecque-Gilbert, Marie-Maxime, Processes for preparing titanium oxide and various other products.
Boudreault, Richard; Fournier, Joël; Simoneau, Raymond; Garcia, Maria Cristina; Primeau, Denis; Krivanec, Heinz; Dittrich, Carsten, Processes for recovering rare earth elements from various ores.
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