When the county board of any county issues bonds to refund the bonded indebtedness of any precinct in the State of Nebraska, and in case an exchange of said refunding bonds cannot be effected, the county board is hereby authorized to sell said refunding bonds from time to time, in such sums as may be necessary to create a fund for the redemption of the outstanding bonds aforesaid and pay interest on such bonds to the date of redemption. The money realized from the sale of said refunding bonds shall not be expended or used for any other purpose than for refunding said outstanding bonds and interest on the bonds.