Issuance of certificates.

The certificates shall bear interest at a rate to be fixed by the state treasurer at the time of issuance and sale. Such interest shall not exceed three percent a year, payable semiannually on January 1 and July 1 of each year from the state general fund; both principal and interest shall be payable at the office of the state treasurer. The certificates shall be signed by the secretary of finance and administration and by the state treasurer; the coupons attached thereto, if any, for the semiannual interest shall bear the signature of the state treasurer. The certificates shall be sold at not less than par and when so sold, the amount of the proceeds thereof shall be placed in a special fund and a separate account thereof shall be kept. All payments made from this special fund shall be made on the warrant or transfer order of the department of finance and administration.