Ill. Admin. Code tit. 11, § 1800.625
b) If the petitioner believes the Administrative Law Judge is biased or has a conflict of interest, the petitioner may file with the Board a motion to disqualify the Administrative Law Judge from conducting the hearing. The motion must be in writing, accompanied by an affidavit signed and dated by the petitioner setting forth the specific grounds for disqualification. The petitioner shall serve a copy of the motion on the Administrative Law Judge. Prior adverse rulings against the petitioner or its attorney in other matters shall not, in and of themselves, constitute grounds for disqualification. On satisfactory evidence submitted by the petitioner in support of the motion to disqualify, the Board shall remove the Administrative Law Judge and provide for the reassignment of the case to another Administrative Law Judge to continue the hearing. Any Administrative Law Judge may voluntarily disqualify himself upon determining that bias or conflict of interest exists. Grounds for disqualification of Administrative Law Judge shall include but not be limited to:
4) Demonstrable pre-disposition on the issues.