Method for preparing type II anhydrous gypsum by fluidizing and roasting beta-semi-hydrated gypsum

• Main Authors: MA LIPING, WANG YUE, GUO ZHIYING, HOU PEIXIN, DU WANG, LI KAI, QING SANCHENG, XIONG XIONG, YIN XIA, AO RAN, MU LIUSEN, PAN QINGHUAN, LI JIAWEI
• Format: Patent
• Language: Chinese; English
• Published: 23.07.2021
• Subjects: ARTIFICIAL STONE; CEMENTS; CERAMICS; CHEMISTRY; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; CONCRETE; LIME, MAGNESIA; METALLURGY; REFRACTORIES; SLAG; TREATMENT OF NATURAL STONE

The invention discloses a method for preparing type II anhydrous gypsum by fluidizing and roasting beta-semi-hydrated gypsum, which comprises the following steps: step 1, fluidizing and roasting beta-semi-hydrated gypsum powder in a small fluidized bed, keeping the gas-solid ratio at 0.2320-0.2680 L.( g.min)-1, and controlling the heating rate at 5-15 DEG C/min; 2, when the temperature of a roasting furnace is increased to 700-900 DEG C, carrying out heat preservation for 100-200 min; 3, after the heat preservation stage is finished, naturally cooling to normal temperature, and taking out the gypsum. According to the method, efficient mass transfer and heat transfer of the fluidized bed are utilized, the roasting efficiency is improved, and the content of the II-type anhydrous gypsum can reach 85% or above; impurities can be removed through high-temperature fluidized roasting, and the quality of the II-type anhydrous phosphogypsum subjected to high-temperature roasting is slightly influenced by the impurities