Adding bulk to a paper/cardboard fiber suspension uses an additive of calcium oxide or hydroxide for exposure to power plant exhaust gas in a reactor to form deposits of calcium carbonate on the fiber surfaces

摘要

To add a charge of bulking materials to a fiber suspension, to be used for the production of paper or cardboard, calcium oxide and/or calcium hydroxide are used to form a deposit of calcium carbonate on the saturated fiber surfaces in the suspension (14). At least a part of the additive associates with the water of the suspension. The treated suspension is exposed to the exhaust gas from the power plant of the paper factory and/or with an exhaust gas containing carbon dioxide. To add bulk to a paper/cardboard fiber suspension, the power plant exhaust gas is cleaned in at least one stage before it makes contact with the suspension fibers. The process also uses the heat carried by the exhaust gas. The calcium oxide and/or calcium hydroxide are added to the fiber suspension at a rate of 0.1-60.0 wt.% in relation to the suspension dry content. The suspension with the additives is treated with carbon dioxide in the hot exhaust gas in a closed vessel or Fiber Loading reactor (24), where the gas is fed in under pressure, to form a calcium carbonate deposit on the fiber surfaces. The calcium carbonate is deposited within hollow fibers as well as on their wall surfaces. In addition, CaCO3 is added to the fiber suspension. The carbon dioxide gas is fed into the reactor at a higher pressure than the internal reactor pressure and/or preferably at ambient temperatures, raised temperatures or at the reactor temperature. The gas pressure and/or temperature is controlled before it enters the reactor.