首页|Copper slag assisted coke reduction of phosphogypsum for sulphur dioxide preparation

Copper slag assisted coke reduction of phosphogypsum for sulphur dioxide preparation

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The reduction of phosphogypsum(PG)to lime slag and SO2 using coke can effectively alleviate the envi-ronmental problems caused by PG.However,the PG decomposition temperature remains high and the product yield remains poor.By adding additives,the decomposition temperature can be further reduced and PG decomposition rate and product yield can be improved.However,the use of current additives such as Fe2O3 and SiO2 brings the problem of increasing economic cost.Therefore,it is proposed to use solid waste copper slag(CS)as a new additive to reduce PG to prepare SO2,which can reduce the cost and meet the environmental benefits at the same time.The effects of proportion,temperature and ther-mostatic time on PG decomposition are investigated by experimental and kinetic analysis combined with FactSage thermodynamic calculations to optimize the roasting conditions.Finally,the reaction mecha-nism is proposed.It is found that adding CS to the coke and PG system can increase the rate of PG decom-position and SO2 yield while lowering the PG decomposition temperature.For example,when the CS/PG mass ratio increases from 0 to 1,PG decomposition rate increases from 83.38%to 99.35%,SO2 yield increases from 78.62%to 96.81%,and PG decomposition temperature decreases from 992.4 ℃ to 949.6 ℃.The optimal reaction parameters are CS/PG mass ratio of 1,Coke/PG mass ratio of 0.06 at 1100 ℃ for 20 min with 99.35%PG decomposition rate and 96.81%SO2 yield.The process proceeds according to the following reactions:2CaSO4+0.7C+0.8Fe2SiO4 → 0.8Ca2SiO4+0.2Ca2Fe2O5+0.4Fe3O4+2SO2+0.7CO2 Finally,a process for decomposing PG with coke and CS is proposed.

PhosphogypsumSulfur dioxideCopper slagFluidized-bedReductionWaste treatment

Dong Ma、Qinhui Wang

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State Key Laboratory of Clean Energy Utilization,Institute for Thermal Power Engineering,Zhejiang University,Hangzhou 310027,China

schoolenterprise cooperation projects

2019-KYY-508101-0078

2024

中国化学工程学报(英文版)
中国化工学会

中国化学工程学报(英文版)

CSTPCDEI
影响因子:0.818
ISSN:1004-9541
年,卷(期):2024.65(1)
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