For purposes of this chapter, section 1821 (b)(1) of this title (relating to limit on decrease in duty), sections 1841, 1843, and 1844 of this title (relating to certain requirements concerning negotiations), and section 1883 of this title (relating to staging requirements) shall not apply with respect to dicyandiamide provided for in item 425.40 of the Tariff Schedules of the United States, and shall not apply with respect to limestone, when imported to be used in the manufacture of cement, provided for in item 513.34 of such Schedules.