Method for preparing calcium sulfate from ardealite

[0038] The raw material of this embodiment is phosphogypsum provided by Hubei Xingfa Chemical Group Co., Ltd. Its main components are: CaO 28.98%, P 2 o 5 1.09%, SiO 2 6.06%, MgO 0.18%, Al 2 o 3 0.42%, SO 3 42.32%, CaSO 4 70.36%, crystal water 16.01%. X-ray diffraction analysis shows that the main component of phosphogypsum is CaSO 4 , followed by SiO 2 , and a small amount of colloidal phosphate and aluminosilicate.

[0039] The present embodiment prepares the circulation process of high-purity calcium sulfate by phosphogypsum, is characterized in that comprising the steps:

[0040] (1) Decompose phosphogypsum with NaOH solution: slowly add NaOH solution with a concentration of 2.40mol / L to the reactor containing phosphogypsum raw materials according to the dosage of 11.4mol NaOH / 1kg phosphogypsum, and stir while adding , reacted at room temperature for 10 min. Then the slurry is filtered, and the filter residue is countercurrently washed twice to obtain Na wit

[0053] The raw material of this embodiment is phosphogypsum provided by Hubei Xingfa Chemical Group Co., Ltd. Its main components are: CaO 28.98%, P 2 o 5 1.09%, SiO 2 6.06%, MgO 0.18%, Al 2 o 3 0.42%, SO 3 42.32%, CaSO 4 70.36%, crystal water 16.01%. X-ray diffraction analysis shows that the main component of phosphogypsum is CaSO 4 , followed by SiO 2 , and a small amount of colloidal phosphate and aluminosilicate.

[0054] The present embodiment prepares the circulation process of high-purity calcium sulfate by phosphogypsum, is characterized in that comprising the steps:

[0055] (1) Decompose phosphogypsum with KOH solution: slowly add KOH solution with a concentration of 1.80mol / L to the reactor containing phosphogypsum raw material according to the amount of 10mol NaOH / 1kg phosphogypsum, and stir while adding, React at room temperature for 20 min. Then the slurry is filtered, and the filter residue is countercurrently washed twice to obtain a K concentrat

[0066] The raw material of this embodiment is phosphogypsum provided by Hubei Xingfa Chemical Group Co., Ltd. Its main components are: CaO 28.98%, P 2 o 5 1.09%, SiO 2 6.06%, MgO 0.18%, Al 2 o 3 0.42%, SO 3 42.32%, CaSO 4 70.36%, crystal water 16.01%. X-ray diffraction analysis shows that the main component of phosphogypsum is CaSO 4 , followed by SiO 2 , and a small amount of colloidal phosphate and aluminosilicate.

[0067] The present embodiment prepares the circulation process of high-purity calcium sulfate by phosphogypsum, is characterized in that comprising the steps:

[0068] (1) Decompose phosphogypsum with KOH solution: slowly add the NaOH solution with a concentration of 2.60mol / L to the reactor containing the phosphogypsum raw material according to the amount of 12mol KOH / 1kg phosphogypsum, and stir while adding, React at room temperature for 8 minutes. Then the slurry is filtered, and the filter residue is countercurrently washed twice to obtain a K