磷石膏分解特性的研究
|
摘要
磷化工业的迅速发展带来了磷石膏的综合利用和硫酸需求量增加两大问题。本文提出的磷石膏流态化分解制硫酸联产石灰工艺是符合我国国情的资源化利用磷石膏的有效途径。因此,开展磷石膏分解特性的研究具有重要的实用价值和理论意义。
第一,采用XRD、XRF、激光粒度分析、高温显微镜等方法研究了有代表性的贵州瓮福磷石膏的基本特性。结果表明,磷石膏主要矿物成分为CaSO_4.2H_2O,纯度高,干基CaO含量一般在30%左右,SO_3含量35～45%,是一种优质的制硫酸联产石灰原料;颗粒粒径≤0.075mm的颗粒达91.25%,因此可不用粉磨,烘干破碎后直接分解制酸;磷石膏中的杂质降低了CaSO_4的熔点,1200℃以后有可能产生液相,磷石膏熔点在1280℃左右,随杂质含量的变化而略有不同。
第二,采用HSC热力学计算软件,经过热力学计算,研究了磷石膏在还原分解的过程中可能发生的反应,并进行了理论热耗的计算。结果表明,CO和焦炭均能降低CaSO_4的起始分解温度和理论热耗,但是低温条件下易发生副反应生成CaS,应避免低温预热过程中形成CaS。
第三,采用热综合分析法,对比研究了化学分析纯石膏在空气和氮气中的分解特性、化学分析纯石膏掺不同剂量的焦炭在氮气气氛保护下的分解特性、磷石膏在空气和氮气中的分解特性、磷石膏掺焦炭分别在氮气气氛保护下和在空气中的分解特性。结果表明,磷石膏中所含杂质降低了CaSO_4的起始分解温度,对分解有促进作用;在N_2气氛下焦炭掺量对还原分解CaSO_4的最终产物有重要影响,掺量为C/S=0.5时主要产物为CaO,当C/S=2时主要产物为CaS,CaS在1100℃以上约1200℃左右、3%O_2浓度的高温低氧条件下能被缓慢氧化为CaO并释放出SO_2。
第四,采用分散态磷石膏的高温气氛炉模拟试验研究了分散态磷石膏的分解特性。结果表明,温度和气氛是影响磷石膏分解的最重要因素,弱还原气氛有利于磷石膏的分解,在高温气氛炉模拟试验条件下,适合磷石膏的分解条件是1000℃～1100℃,CO:3%～5%,CO_2体积分数为25%～30%,反应时间20min,预计流态化条件下分解时间仅需15-30s,分解率达到95%左右,脱硫率85%左右。
最后,综合分析磷石膏分解特性的研究结果,就磷石膏分解制硫酸联产石灰的工艺提出了建议。
The rapid development of phosphorous chemical industry brings about two problems,which are the comprehensive utilization of phosphogypsum(PG) and the quick increasement of sulphuric acid demand.The process of producing sulphuric acid and lime with the fluidizedpyrolysis of PG is a good way to solve the two ploblems mentioned above,which tally with the national condition.Therefore,the research of the phosphogypsum decomposition characteristics has important practical value and theoretical significance.
Firstly,XRD,XRF,laser particle size analyzing and high temperature microscope tests were used to study the basic characteristics of PG from Wenfu in Guizhou.The results showed that the main mineral composition of PG is CaSO_4·2H_2O,and the content(dry basis) of CaO and SO_3 are about 30%and 35 45%respectively,which shows it is a high-quality raw materials for sulfuric acid and lime generation.Besides,particles with the size≤0.075mm are more than 91.25%, so the raw material may be directly used to produce acid after being crushed and dried.Also,the results showed that the impurity in PG causes the lowering of melting point to approximately 1280℃,and liquid phase may occur after 1200℃, which differs with the variation of impurity content.
Secondly,HSC Chemistry was used to study the reactions in the reductive decomposition of PG.The results of thermodynamic calculation showed that CO and carbon both lower initial decomposition temperature and theoretical heat consumption.However,CaS is easily generated under low temperature conditions. Therefore,the formation of CaS should be avoided in the course of low-temperature pre-heating of PG.
Thirdly,thermal analysis was used to comparatively study the decomposition characteristics of chemical reagents CaSO_4·2H_2O in the air and the nitrogen atmosphere,chemical reagents CaSO_4·2H_2O mixed in different doses of coke in the nitrogen atmosphere,PG in the air and nitrogen atmosphere,and PG mixed coke in the air and the nitrogen.The results showed that the impurity in PG lowers its initial decomposition temperature and promotes the decomposition.In the nitrogen atmosphere,coke dose has a great influence on the decomposition result of CaSO_4. The main product is CaO in the case of C/S=0.5,while CaS becomes the main product in the case of C/S=2.Under the condition of 1100℃～1200℃,O_2=3%,CaS can be slowly oxidized to CaO,releasing SO_2.
Fourthly,high-temperature atmosphere furnace tests were used to study the decomposition characteristics of PG in decentralized state.The results showed that temperature and atmosphere are the most important factors that affect the decomposition of PG.Weakly reducing atmosphere is beneficial for the decomposition of PG.In the tests,the best decomposition condition for PG is 1000℃～1100℃,3%～5%CO,25%～30%CO_2,and 20min of decomposition time. Under this condition,decomposition degree can reach 95%while desulfurization degree can exceed 85%.Under fluidization condition,the decomposition time needed is expected to be 15～30 seconds.
Lastly,suggestions are given for the process of producing sulphuric acid and lime with the fluidizedpyrolysis of PG according to the research results of PG decomposition characteristics.
第一,采用XRD、XRF、激光粒度分析、高温显微镜等方法研究了有代表性的贵州瓮福磷石膏的基本特性。结果表明,磷石膏主要矿物成分为CaSO_4.2H_2O,纯度高,干基CaO含量一般在30%左右,SO_3含量35～45%,是一种优质的制硫酸联产石灰原料;颗粒粒径≤0.075mm的颗粒达91.25%,因此可不用粉磨,烘干破碎后直接分解制酸;磷石膏中的杂质降低了CaSO_4的熔点,1200℃以后有可能产生液相,磷石膏熔点在1280℃左右,随杂质含量的变化而略有不同。
第二,采用HSC热力学计算软件,经过热力学计算,研究了磷石膏在还原分解的过程中可能发生的反应,并进行了理论热耗的计算。结果表明,CO和焦炭均能降低CaSO_4的起始分解温度和理论热耗,但是低温条件下易发生副反应生成CaS,应避免低温预热过程中形成CaS。
第三,采用热综合分析法,对比研究了化学分析纯石膏在空气和氮气中的分解特性、化学分析纯石膏掺不同剂量的焦炭在氮气气氛保护下的分解特性、磷石膏在空气和氮气中的分解特性、磷石膏掺焦炭分别在氮气气氛保护下和在空气中的分解特性。结果表明,磷石膏中所含杂质降低了CaSO_4的起始分解温度,对分解有促进作用;在N_2气氛下焦炭掺量对还原分解CaSO_4的最终产物有重要影响,掺量为C/S=0.5时主要产物为CaO,当C/S=2时主要产物为CaS,CaS在1100℃以上约1200℃左右、3%O_2浓度的高温低氧条件下能被缓慢氧化为CaO并释放出SO_2。
第四,采用分散态磷石膏的高温气氛炉模拟试验研究了分散态磷石膏的分解特性。结果表明,温度和气氛是影响磷石膏分解的最重要因素,弱还原气氛有利于磷石膏的分解,在高温气氛炉模拟试验条件下,适合磷石膏的分解条件是1000℃～1100℃,CO:3%～5%,CO_2体积分数为25%～30%,反应时间20min,预计流态化条件下分解时间仅需15-30s,分解率达到95%左右,脱硫率85%左右。
最后,综合分析磷石膏分解特性的研究结果,就磷石膏分解制硫酸联产石灰的工艺提出了建议。
The rapid development of phosphorous chemical industry brings about two problems,which are the comprehensive utilization of phosphogypsum(PG) and the quick increasement of sulphuric acid demand.The process of producing sulphuric acid and lime with the fluidizedpyrolysis of PG is a good way to solve the two ploblems mentioned above,which tally with the national condition.Therefore,the research of the phosphogypsum decomposition characteristics has important practical value and theoretical significance.
Firstly,XRD,XRF,laser particle size analyzing and high temperature microscope tests were used to study the basic characteristics of PG from Wenfu in Guizhou.The results showed that the main mineral composition of PG is CaSO_4·2H_2O,and the content(dry basis) of CaO and SO_3 are about 30%and 35 45%respectively,which shows it is a high-quality raw materials for sulfuric acid and lime generation.Besides,particles with the size≤0.075mm are more than 91.25%, so the raw material may be directly used to produce acid after being crushed and dried.Also,the results showed that the impurity in PG causes the lowering of melting point to approximately 1280℃,and liquid phase may occur after 1200℃, which differs with the variation of impurity content.
Secondly,HSC Chemistry was used to study the reactions in the reductive decomposition of PG.The results of thermodynamic calculation showed that CO and carbon both lower initial decomposition temperature and theoretical heat consumption.However,CaS is easily generated under low temperature conditions. Therefore,the formation of CaS should be avoided in the course of low-temperature pre-heating of PG.
Thirdly,thermal analysis was used to comparatively study the decomposition characteristics of chemical reagents CaSO_4·2H_2O in the air and the nitrogen atmosphere,chemical reagents CaSO_4·2H_2O mixed in different doses of coke in the nitrogen atmosphere,PG in the air and nitrogen atmosphere,and PG mixed coke in the air and the nitrogen.The results showed that the impurity in PG lowers its initial decomposition temperature and promotes the decomposition.In the nitrogen atmosphere,coke dose has a great influence on the decomposition result of CaSO_4. The main product is CaO in the case of C/S=0.5,while CaS becomes the main product in the case of C/S=2.Under the condition of 1100℃～1200℃,O_2=3%,CaS can be slowly oxidized to CaO,releasing SO_2.
Fourthly,high-temperature atmosphere furnace tests were used to study the decomposition characteristics of PG in decentralized state.The results showed that temperature and atmosphere are the most important factors that affect the decomposition of PG.Weakly reducing atmosphere is beneficial for the decomposition of PG.In the tests,the best decomposition condition for PG is 1000℃～1100℃,3%～5%CO,25%～30%CO_2,and 20min of decomposition time. Under this condition,decomposition degree can reach 95%while desulfurization degree can exceed 85%.Under fluidization condition,the decomposition time needed is expected to be 15～30 seconds.
Lastly,suggestions are given for the process of producing sulphuric acid and lime with the fluidizedpyrolysis of PG according to the research results of PG decomposition characteristics.
引文
[1]汤德元,瞿德泸.磷肥和磷酸盐生产工艺.贵州:贵州科技出版社,1990
[2]李滢.磷石膏的综合利用.云南化工,2007,34(6):74-80
[3]彭家惠,万体智,汤玲等.磷石膏中杂质组成形态分布及其对性能的影响.中国建材科技,2000,(6):31-35
[4]杨敏,钱觉时,王智等.杂质对磷石膏应用性能的影响.材料导报,21(6):104-106
[5]吴兆正.我国资源化利用磷石膏的建议.中国建材,2008,(1):65-67
[6]傅伯杰,陈利顶,于秀波等.中国生态环境的新特点及对策.环境科学,2000,21(5):104-106
[7]王海军,徐鹏.我国硫资源利用现状及发展战略.中国非金属矿工业导刊,2007,60(2):12-13
[8]M.C.S.Carvalho,B.van Raij.Calcium sulphate,phosphogypsum and calcium carbonate in theamelioration of acid subsoils for root growth.Plant and Soil,1997,192:37-48
[9]Paolo Battistoni,Enrico Camiani,Valeria Fratesi et al..Chemical-Physical Pretreatment of Phosphogypsum Leachate.Ind.Eng.Chem.Res.,2006,45(9):3237-3242
[10]Mitsuru Toma,Masahiko Saigusa.Effects of phosphogypsum on amelioration of strongly acid nonallophanic andosols.Plant and Soil,1997,192:49-55
[11]何水清,利用磷石膏生产建材.砖瓦世界,2008,(2):23-26
[12]黄新,王海帆.我国磷石膏制硫酸联产水泥的现状.硫酸工业,2000,(3):10-14
[13]闫久智.磷石膏制硫酸联产水泥工艺.磷肥与复肥,2004,19(3):53-55
[14]沈咸.磷石膏制硫酸联产水泥生产线的工艺设计特点.新世纪水泥导报,1998,4(5)22-23
[15]蒋永安.磷石膏制硫酸联产水泥的装置情况介绍.硫酸工业,2002,(6):5-10
[16]胡振玉.磷石膏制硫酸联产水泥机理与应用研究.[博士学位论文].北京:北京科技大学安全技术及工程,2004
[17]张巫兴.磷石膏低碱度水泥及其水化特性.硅酸盐通报,1996,2:19-24
[18]宋廷寿,芦令超,胡佳山.用磷石膏烧成硫铝酸盐水泥的研究.水泥,1999,2:4-6
[19]路向前.磷石膏在水泥工业中的应用.国外建材科技,2003,(5):8-10
[20]Singh,Manjit.Treating waste phosphogypsum for cement and plaster manufacture.Cement and Concrete Research,2002,32(7):1033-1038
[21]高大庆.利用磷石膏作水泥缓凝剂综述.中国建材,1995,(7):27-28
[22]张昌清.磷石膏制水泥缓凝剂工艺述评北.化学工业与工程技术.2003,(3):18-20
[23]周丽娜,周明凯,赵青林等.不同改性处理方法对磷石膏水泥调凝剂性能的影响.水泥,2007.8:16-18
[24]周丽娜.复合改磷石膏做水泥调凝剂的研究.[硕士学位论文].武汉:武汉理工大学材料学,2007
[25]Olmez,H.,Erdem,E..Effects of phosphogypsum on the setting and mechanical properties of portland cement and trass cement.Cement and Concrete Research,1989,19(3):377-384
[26]Samir I.Abu-Eishah,Ali A.Bani-Kananeh,Mamdouh A.Allawzi.K_2SO_4 production via the double decomposition reaction of KCl and phosphogypsum.Chemical Engineering Journal,2000,76(3):197-207
[27]曹广秀,曹广连,马淮凌.磷石膏一步法制取硫酸钾工艺研究.2005,34(7):421-423
[28]刘晓红.磷石膏制硫酸钾中试研究.环境工程,2004,22(4):76-78
[29]杨启山,杜凤毅,高丽娟等.浅析磷石膏综合利用与提取稀土.稀土,2007,28(1):99-101
[30]卢忠远.利用磷石膏生产陶瓷装饰材料.重庆环境科学,1997,19(3):48-49
[31]沈卫国,周明凯,余崇峻等.磷石膏改性二灰路面基层材料的性能研究.武汉理工大学学报,2003,25(10):34-38
[32]周松林,胡道和,张薇等.磷石膏分解工业反应动力学的研究.化肥工业,1994,(2):16-22
[33]刘述祖.水泥悬浮预热与窑外分解技术.武汉:武汉工业大学出版社,1995
[34]彭新战,胡道和.磷石膏分解炉的研究与开发进展.硫酸工业,1993(5):43-48
[35]张薇,简淼夫,周松林等.悬浮状态下磷石膏分解规律的研究.南京化工学院学报,1994.16:84-88
[36]张少明,彭新战,周永敏等.磷石膏流化床分解技术的研究.化肥工业,1994(3):28-31
[37]黄南樾,谢朝晖,孙勇等.用流态化分解炉分解磷石膏的试验研究.水泥工程,1996,(4):4-6
[38l马林转.循环流化床分解磷石膏及分解气体资源化研究.[博士学位论文].云南:昆明理工大学资环系,2006
[39]周松林,胡道和,肖国先.磷石膏分解反应机理及影响因素浅析.新世纪水泥导报,1998,4(5):16-18
[40]R.kuusik*,ESaikkonen,et al.Thermal decomposition of calcium sulfate in carbon monoxide.Journal of Thermal Analysis,1985,30:187-193
[41]C.A.Strydom 1,E.M.Groenewald,J.H.Potgieter.Thermogravimetric studies of the synthesis of CaS from gypsum,CaSO_4·2H_2O and phosphogypsum.Journal of Thermal Analysis,1997,49:1501-1507
[42]Naoto Mihara,Dalibor Kuchar,Yoshihiro Kojima,et al.Reductive decomposition of waste gypsum with SiO_2,Al_2O_3,and Fe_2O_3 additives.J Mater Cycles Waste Manag,2007,(9):21-26
[43]H.Y.S OH N *,Byung-Sukim.A New Process for Converting SO_2 to Sulfur without Generating Secondary Pollutants through Reactions Involving CaS and CaSO4.Environ.Sci.Technol,2002,(36):3020-3024
[44]E.M.van der Merwe,C.A.Strydom,J.H.Potgieter.Thermogravimetric analysis of the reaction between carbon and CaSO_4·2H_2O,gypsum and phosphogypsum in an inert atmosphere.Thermochimica Acta,1999,340:431-437
[45]R.kuusik*,P.Saikkonen,et al.Thermal decomposition of calcium sulfate in carbon monoxide.Journal of Thermal Analysis,1985,30:187-193
[46]Iv.Gruncharov,Y.Pelovski,G.Bechev,et al.Effects of some admixtures on the decomposition of calcium sulfate.Journal of Thermal Analysis,1988,33:597-602
[47]Iv.Gruncharov.Effects of additives during the thermochemical decomposition of phosphogypsum under isothermal conditions.Journal of Thermal Analysis,1987,32:1739-1742
[48]Iv.Gruncharov,P1.Kirilov,Y.Pelovski,et al.Isothermal gravimetrical kinetic study of the decomposition of phosphogypsum under CO-CO_2-Ar atmosphere.Thermochimica Acta,1985,92(15):173-176
[49]T.D.Wheelock,D.R.Boylan.Reductive decomposition of gypsum by carbon monoxide.Industrial and Engineering Chemistry,1960,52(3):215-218
[50]周松林,肖国先.磷石膏分解过程的模拟试验研究.水泥工程,1998,(5):5-7
[51]肖国先,周松林,胡道和.磷石膏还原分解动力学研究.水泥技术,1998,(4):22-24
[52]肖国先,周松林,胡道和.磷石膏在还原--氧化双气氛下的分解反应动力学研究.水泥,1997,(8):1-3
[53]王成波,张志业,陈欣.磷石膏生产硫酸联产水泥用新型还原剂的实验研究.磷肥与复肥,2007,22(1):21-23
[54]张学丽,韩利华.磷石膏制硫酸联产水泥工艺条件的研究.山东化工,2007,36(1)26-27
[55]周松林,胡道和,肖国先等.分散态磷石膏分解动力学模拟试验研究.磷石膏分解新技术研究专题报告1991,5-19
[2]李滢.磷石膏的综合利用.云南化工,2007,34(6):74-80
[3]彭家惠,万体智,汤玲等.磷石膏中杂质组成形态分布及其对性能的影响.中国建材科技,2000,(6):31-35
[4]杨敏,钱觉时,王智等.杂质对磷石膏应用性能的影响.材料导报,21(6):104-106
[5]吴兆正.我国资源化利用磷石膏的建议.中国建材,2008,(1):65-67
[6]傅伯杰,陈利顶,于秀波等.中国生态环境的新特点及对策.环境科学,2000,21(5):104-106
[7]王海军,徐鹏.我国硫资源利用现状及发展战略.中国非金属矿工业导刊,2007,60(2):12-13
[8]M.C.S.Carvalho,B.van Raij.Calcium sulphate,phosphogypsum and calcium carbonate in theamelioration of acid subsoils for root growth.Plant and Soil,1997,192:37-48
[9]Paolo Battistoni,Enrico Camiani,Valeria Fratesi et al..Chemical-Physical Pretreatment of Phosphogypsum Leachate.Ind.Eng.Chem.Res.,2006,45(9):3237-3242
[10]Mitsuru Toma,Masahiko Saigusa.Effects of phosphogypsum on amelioration of strongly acid nonallophanic andosols.Plant and Soil,1997,192:49-55
[11]何水清,利用磷石膏生产建材.砖瓦世界,2008,(2):23-26
[12]黄新,王海帆.我国磷石膏制硫酸联产水泥的现状.硫酸工业,2000,(3):10-14
[13]闫久智.磷石膏制硫酸联产水泥工艺.磷肥与复肥,2004,19(3):53-55
[14]沈咸.磷石膏制硫酸联产水泥生产线的工艺设计特点.新世纪水泥导报,1998,4(5)22-23
[15]蒋永安.磷石膏制硫酸联产水泥的装置情况介绍.硫酸工业,2002,(6):5-10
[16]胡振玉.磷石膏制硫酸联产水泥机理与应用研究.[博士学位论文].北京:北京科技大学安全技术及工程,2004
[17]张巫兴.磷石膏低碱度水泥及其水化特性.硅酸盐通报,1996,2:19-24
[18]宋廷寿,芦令超,胡佳山.用磷石膏烧成硫铝酸盐水泥的研究.水泥,1999,2:4-6
[19]路向前.磷石膏在水泥工业中的应用.国外建材科技,2003,(5):8-10
[20]Singh,Manjit.Treating waste phosphogypsum for cement and plaster manufacture.Cement and Concrete Research,2002,32(7):1033-1038
[21]高大庆.利用磷石膏作水泥缓凝剂综述.中国建材,1995,(7):27-28
[22]张昌清.磷石膏制水泥缓凝剂工艺述评北.化学工业与工程技术.2003,(3):18-20
[23]周丽娜,周明凯,赵青林等.不同改性处理方法对磷石膏水泥调凝剂性能的影响.水泥,2007.8:16-18
[24]周丽娜.复合改磷石膏做水泥调凝剂的研究.[硕士学位论文].武汉:武汉理工大学材料学,2007
[25]Olmez,H.,Erdem,E..Effects of phosphogypsum on the setting and mechanical properties of portland cement and trass cement.Cement and Concrete Research,1989,19(3):377-384
[26]Samir I.Abu-Eishah,Ali A.Bani-Kananeh,Mamdouh A.Allawzi.K_2SO_4 production via the double decomposition reaction of KCl and phosphogypsum.Chemical Engineering Journal,2000,76(3):197-207
[27]曹广秀,曹广连,马淮凌.磷石膏一步法制取硫酸钾工艺研究.2005,34(7):421-423
[28]刘晓红.磷石膏制硫酸钾中试研究.环境工程,2004,22(4):76-78
[29]杨启山,杜凤毅,高丽娟等.浅析磷石膏综合利用与提取稀土.稀土,2007,28(1):99-101
[30]卢忠远.利用磷石膏生产陶瓷装饰材料.重庆环境科学,1997,19(3):48-49
[31]沈卫国,周明凯,余崇峻等.磷石膏改性二灰路面基层材料的性能研究.武汉理工大学学报,2003,25(10):34-38
[32]周松林,胡道和,张薇等.磷石膏分解工业反应动力学的研究.化肥工业,1994,(2):16-22
[33]刘述祖.水泥悬浮预热与窑外分解技术.武汉:武汉工业大学出版社,1995
[34]彭新战,胡道和.磷石膏分解炉的研究与开发进展.硫酸工业,1993(5):43-48
[35]张薇,简淼夫,周松林等.悬浮状态下磷石膏分解规律的研究.南京化工学院学报,1994.16:84-88
[36]张少明,彭新战,周永敏等.磷石膏流化床分解技术的研究.化肥工业,1994(3):28-31
[37]黄南樾,谢朝晖,孙勇等.用流态化分解炉分解磷石膏的试验研究.水泥工程,1996,(4):4-6
[38l马林转.循环流化床分解磷石膏及分解气体资源化研究.[博士学位论文].云南:昆明理工大学资环系,2006
[39]周松林,胡道和,肖国先.磷石膏分解反应机理及影响因素浅析.新世纪水泥导报,1998,4(5):16-18
[40]R.kuusik*,ESaikkonen,et al.Thermal decomposition of calcium sulfate in carbon monoxide.Journal of Thermal Analysis,1985,30:187-193
[41]C.A.Strydom 1,E.M.Groenewald,J.H.Potgieter.Thermogravimetric studies of the synthesis of CaS from gypsum,CaSO_4·2H_2O and phosphogypsum.Journal of Thermal Analysis,1997,49:1501-1507
[42]Naoto Mihara,Dalibor Kuchar,Yoshihiro Kojima,et al.Reductive decomposition of waste gypsum with SiO_2,Al_2O_3,and Fe_2O_3 additives.J Mater Cycles Waste Manag,2007,(9):21-26
[43]H.Y.S OH N *,Byung-Sukim.A New Process for Converting SO_2 to Sulfur without Generating Secondary Pollutants through Reactions Involving CaS and CaSO4.Environ.Sci.Technol,2002,(36):3020-3024
[44]E.M.van der Merwe,C.A.Strydom,J.H.Potgieter.Thermogravimetric analysis of the reaction between carbon and CaSO_4·2H_2O,gypsum and phosphogypsum in an inert atmosphere.Thermochimica Acta,1999,340:431-437
[45]R.kuusik*,P.Saikkonen,et al.Thermal decomposition of calcium sulfate in carbon monoxide.Journal of Thermal Analysis,1985,30:187-193
[46]Iv.Gruncharov,Y.Pelovski,G.Bechev,et al.Effects of some admixtures on the decomposition of calcium sulfate.Journal of Thermal Analysis,1988,33:597-602
[47]Iv.Gruncharov.Effects of additives during the thermochemical decomposition of phosphogypsum under isothermal conditions.Journal of Thermal Analysis,1987,32:1739-1742
[48]Iv.Gruncharov,P1.Kirilov,Y.Pelovski,et al.Isothermal gravimetrical kinetic study of the decomposition of phosphogypsum under CO-CO_2-Ar atmosphere.Thermochimica Acta,1985,92(15):173-176
[49]T.D.Wheelock,D.R.Boylan.Reductive decomposition of gypsum by carbon monoxide.Industrial and Engineering Chemistry,1960,52(3):215-218
[50]周松林,肖国先.磷石膏分解过程的模拟试验研究.水泥工程,1998,(5):5-7
[51]肖国先,周松林,胡道和.磷石膏还原分解动力学研究.水泥技术,1998,(4):22-24
[52]肖国先,周松林,胡道和.磷石膏在还原--氧化双气氛下的分解反应动力学研究.水泥,1997,(8):1-3
[53]王成波,张志业,陈欣.磷石膏生产硫酸联产水泥用新型还原剂的实验研究.磷肥与复肥,2007,22(1):21-23
[54]张学丽,韩利华.磷石膏制硫酸联产水泥工艺条件的研究.山东化工,2007,36(1)26-27
[55]周松林,胡道和,肖国先等.分散态磷石膏分解动力学模拟试验研究.磷石膏分解新技术研究专题报告1991,5-19