"Bauer-DJ" . . "Eichbaum-BR" . . . "Acid process for recovery of alumina from clay"@en . . . . . . . "1978-06-13T00:00:00Z"^^ . . . "10012037" . "Acid process for recovery of alumina from clay"@en . . . . "Acid process for recovery of alumina from clay"@en . . . . . . "Acid process for recovery of alumina from clay"@en . "US4094955" . "patent published in 1978"@en . . "Eisele-JA" .