CN103072949A - Method for preparing calcium sulfide through reductive decomposition of phosphogypsum by fluidized bed - Google Patents
Method for preparing calcium sulfide through reductive decomposition of phosphogypsum by fluidized bed Download PDFInfo
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- CN103072949A CN103072949A CN2012105223863A CN201210522386A CN103072949A CN 103072949 A CN103072949 A CN 103072949A CN 2012105223863 A CN2012105223863 A CN 2012105223863A CN 201210522386 A CN201210522386 A CN 201210522386A CN 103072949 A CN103072949 A CN 103072949A
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Abstract
The invention discloses a method for preparing calcium sulfide through the reductive decomposition of phosphogypsum by a fluidized bed. The method comprises the following steps: mixing coal dust and phosphogypsum according to a mass ratio of the coal dust to phosphogypsum of 0.5-3:1, reacting at 800-950DEG C, separating the obtained tail gas containing solid particles through a cyclone separator, dedusting through a bag deduster, sending the tail gas to a tail gas absorber through an induced draught fan, returning the tail gas to the fluidized bed through a pipeline for generating a CO reduction gas having a concentration of 5-12%, and carrying out cycle decomposition to obtain CaS, wherein the returning amount is 30-100% of the amount of the tail gas. Compared with traditional methods for the reductive decomposition of phosphogypsum through a rotary kiln, the method disclosed in the invention has the advantages of large processing capacity, short reaction time, full utilization of heat of the tail gas and the reduction gas, small apparatus land occupation area and the like.
Description
Technical field
The present invention relates to the method that a kind of fluidization bed reducing and decomposing phosphogypsum prepares sulfurated lime, belong to enviromental protection and improvement and chemical production technical field.
Background technology
Phosphogypsum is the industrial residue that produces in the production process of phosphoric acid, main component CaSO4.China's phosphogypsum quantity discharged has reached 3,000 ten thousand tons at present.China is as the large production of phosphate fertilizer of the first in the world state, simultaneously also is first phosphogypsum by-product state.In the Wet-process Phosphoric Acid Production process, 1 ton of phosphoric acid of every production consumes 2.5～2.8 tons in sulfuric acid, produces 5 tons of phosphogypsums.Phosphogypsum is stacked and is taken a large amount of soils, after rainwater soaks, and solubility P wherein
2O
5With the objectionable constituent such as fluorochemical by water body environment scattering and permeating towards periphery, soil, water, atmosphere are caused severe contamination.
People just expect the gaseous product SO after the phosphogypsum thermal degradation as far back as the beginning of this century
2Be used for respectively producing sulfuric acid and cement with solid product CaO, both solved the processing problem of phosphogypsum slag, opened up new sulphur resource for sulfuric acid industry again, produce simultaneously cement, be expected to form in the production of phosphate fertilizer benign cycle without waste sludge discharge.In succession propose to adopt the new solution of fluidized-bed reactor decomposing phosphogypsum co-producing sulfuric acid and cement both at home and abroad, namely large section burning process of the decomposition of phosphogypsum and cement clinker finished in fluidized-bed and rotary kiln respectively, make and be rich in SO
2Furnace gas and the kiln gas of rotary kiln discharging separately, both strengthened heat transfer and the mass transfer of the maximum decomposition course of caloric receptivity, improved again the SO in the relieving haperacidity gas
2Concentration (can reach 14-16%).In addition, also help the operation and controlling of production process.Developing this new technology can yet be regarded as and improve the effective way of traditional processing technology.
Sixties Mo, the proposition such as the T.DWheelock of American I/O WA state university with the technical scheme of reducing atmosphere preheating and decomposing phosphogypsum, is the rudiment of decomposing ardealite new industrial research in two-layer fluidized-bed.Middle nineteen seventies, abroad some scholars are according to decomposing ardealite study on mechanism achievement, and two-layer fluidized-bed is improved becomes the two atmosphere districts of individual layer fluidized-bed again, namely is divided into reduction zone and oxidation zone in bed, has carried out a large amount of test works.1985, German IJurgi company introduced circulating fluidized bed technique in the decomposing ardealite technological process first, and the development research of this new technology is made substantial progress.Yet not yet can realize at present the target of suitability for industrialized production both at home and abroad to the exploitation of this new technology, also have many technical barriers to remain to be furtherd investigate test.
Phosphogypsum is produced in the research method of sulfurated lime both at home and abroad, mostly rests on laboratory stage, produces the method for fluidisation calcium because of the phosphogypsum reduction, need to be under certain density reducing atmosphere, and needed reducing atmosphere adopts the mode of gas cylinder distribution to reach.In pilot scale or industrial production, have not seen reported.It is that phosphogypsum prepares intermediate product in the sulfuric acid process that phosphogypsum prepares sulfurated lime.Preparation process has two kinds of methods, and the first is " single stage method ", and reaction principle is the main component CaSO of phosphogypsum
4Direct oxidation is CaO, produces simultaneously SO
2The second is " two step method ", CaSO
4Be reduced to first CaS, CaS reduces with reducing gas again, produces SO
2And CaO.Two kinds of methods are respectively each got merits and demerits.The reactor that generally adopts is fluidized-bed and rotary kiln.
Chinese patent application numbers 200710077608.6 discloses a kind of novel method of producing sulfurated lime with phosphogypsum, and the method is after adopting phosphogypsum and coal to mix by a certain percentage, after adding water and making bulk, adopts sintering oven equipment to react, and obtains the sulfurated lime product.
Chinese patent application numbers 200810058185.6 discloses a kind of method of producing calcium sulfide from calcium sulfate, the method is the material take calcium sulfate as main component, take carbon or coke as reductive agent, on cyclone preheater and rotary kiln device, reduction decomposition is the technique of sulfurated lime.
Chinese patent application numbers 200910216326.7 discloses a kind of method of preparing calcium sulfide by reducing and decomposting gypsum through sulfur; the method gypsum under the protection of inert gas condition; add gypsum and carry out the preheating certain hour; then after passing into gaseous state sulphur and gypsum reaction 0.5～2h, obtain the sulfurated lime product.
Above-mentioned preparation method adopts coal or sulphur as reductive agent the calcium sulfate in the gypsum to be reduced to sulfurated lime, exists cost high, little and the problem that can not continuous operation for the treatment of capacity.
Summary of the invention
The present invention be directed to the technology of present preparation sulfurated lime, provide a kind of a large amount of continuously, utilize gas-solid reaction, reaction conditions is easy to control and can takes full advantage of heat, and the fluidization bed reducing and decomposing phosphogypsum of the fine reduction energy consumption of energy prepares the method for sulfurated lime.
Fluidization bed reducing and decomposing phosphogypsum of the present invention prepares the method for sulfurated lime, coal dust and phosphogypsum are mixed, the mass ratio of proportioning is coal: phosphogypsum=0.5～3:1, used coal dust is that the mass percent of carbon content is 65%～80%, coal powder size is 0.75-8mm, after mixing, join in the circulating fluidized bed, temperature is 800～950 ℃ of popular response temperature, the tail gas that contains solid particulate separates through cyclonic separator, after the sack cleaner dedusting, by induced draft fan tail gas is sent into tail gas absorber, and by pipeline tail gas is returned fluidized-bed, returning the living concentration of induced labor by tail gas is 5%～12%CO reducing gas, carry out the circulating fluidization calcining, obtain the CaS product behind the Cycle-decomposition.
Described coal powder fraction content mass percent is 15%～50%, and volatile content is 15%～30%, and coal powder size is 0.75-8mm.
Described phosphogypsum refers to semi-hydrated gypsum, desulfurated plaster.
The described CO concentration of returning in the tail gas is 5%～12%.
Described reactor refers to circulating fluidized bed device.
Described tail gas returns the 30%-100% that the amount of drawing is the tail gas amount.
Described decomposed tail gas partially or completely returns and draws, and as a part of fluidized wind, reduces O in the fluidized wind
2Content increases CO
2Content.Adopt coal dust and gypsum to mix according to mass ratio 0.5～3:1 ratio, temperature is 800～950 ℃ of popular response temperature.
Fluidization bed reducing and decomposing phosphogypsum of the present invention prepares the method for sulfurated lime, adopt circulating fluidized bed as reactor, the material treatment capacity is large and equipment stable, reduced maintenance cost, adopt coal-fired offering on the one hand as thermal source to react needed temperature, CO of its burning generation can directly as reducing gas, need not external CO source of the gas again on the other hand, utilize fully fire coal, saved cost; In addition, partly return decompose the tail gas that produces to or all turn back to fluidized-bed as fluidized wind, can reduce the oxygen level in the fluidized wind, improve the CO gas concentration, improve the CaS content in the product; Next takes full advantage of heat, has reduced hear rate and cost, and has reduced the discharging of waste gas, and final subangle gypsum obtains the sulfurated lime product, wherein still contains a part of coal dust, can directly as the reductive agent of next step relieving haperacidity reaction, further reduce cost.The present invention can be a large amount of continuously, utilize gas-solid reaction, and reaction conditions is easy to control and can takes full advantage of heat, can prepare sulfurated lime by fine reduction energy consumption gas reduction gypsum.
Major advantage of the present invention is:
1) reactor that adopts is circulating fluid bed reactor, and the material treatment capacity is large, and can continuous and steady operation.
2) required reducing gas adopts coal-fired the generation, need not external CO source of the gas, can fine utilization fire coal.
3) decompose the tail gas that produces and partly or entirely return as fluidized wind, take full advantage of heat, reduce hear rate.Reduce the discharging of waste gas.
4) the sulfurated lime product that obtains of decomposing gypsum contains a part of coal dust, can directly as the reductive agent of next step relieving haperacidity reaction, reduce production costs.
Description of drawings
Fig. 1 is schema of the present invention.
Among the figure: 1-feeding machine, 2-fluidized-bed, 3-separator, 4-fly-ash separator, 5-induced draft fan, 6-absorption cell, 7-induced draft fan.
Embodiment
The present invention will be further described below in conjunction with embodiment, but be not limited to embodiment.
Raw material 1: semi-hydrated gypsum
The composition of semi-hydrated gypsum sees the following form:
Raw material 2: raw coal
The raw coal carbon content is 46.89%, and ash content is 44.74%, and volatilization is divided into 18%, and granularity is 3mm.
Implementation method:
Coal dust and semi-hydrated gypsum are after the 0.5:1 ratio mixes according to mass ratio, add circulating fluidized bed device by feeder, the circulating fluidized bed temperature remains on 850 ℃, material residence time in circulating fluidized bed is 1h, the tail gas that contains solid particulate separates through cyclonic separator, after the sack cleaner dedusting, by induced draft fan tail gas is sent into tail gas absorber, and by pipeline tail gas is returned fluidized-bed, it is 70% of tail gas amount that tail gas returns the amount of drawing, producing concentration is 5%～12%CO(volume percent) reducing gas, the product that obtains after the calcining is the CaS product.
Result of implementation:
It is 75% that CaS content 45% in the product, calcium sulfate are converted into the sulfurated lime transformation efficiency.
Raw material 1: used semi-hydrated gypsum is with implementation column 1
Raw material 2: raw coal
The raw coal carbon content is 57.22%, and ash content is 21.94%, and volatilization is divided into 20%, and granularity is 5mm.
Implementation method:
Coal dust and semi-hydrated gypsum are after the 1:1 ratio mixes according to mass ratio, add circulating fluidized bed device by feeder, the circulating fluidized bed temperature remains on 900 ℃, material residence time in circulating fluidized bed is 0.5h, the tail gas that contains solid particulate separates through cyclonic separator, after the sack cleaner dedusting, by induced draft fan tail gas is sent into tail gas absorber, and by pipeline tail gas is returned fluidized-bed, it is 70% of tail gas amount that tail gas returns the amount of drawing, producing concentration is 5%～12%CO(volume percent) reducing gas, the product that obtains after the calcining is the CaS product.
Result of implementation:
It is 80% that CaS content 55% in the product, calcium sulfate are converted into the sulfurated lime transformation efficiency.
Embodiment 3
Raw material 1: desulfurated plaster
The composition of semi-hydrated gypsum sees the following form:
Raw material 2: raw coal
The raw coal carbon content is 46.89%, and ash content is 44.74%, and volatilization is divided into 18%, and granularity is 3mm.
Implementation method:
Coal dust and desulfurated plaster are after the 3:1 ratio is mixed according to mass ratio, add circulating fluidized bed device by feeder, the circulating fluidized bed temperature remains on 950 ℃, material residence time in circulating fluidized bed is 1h, the tail gas that contains solid particulate separates through cyclonic separator, after the sack cleaner dedusting, by induced draft fan tail gas is sent into tail gas absorber, and by pipeline tail gas is returned fluidized-bed, it is 90% of tail gas amount that tail gas returns the amount of drawing, producing concentration is 5%～12%CO(volume percent) reducing gas, the product that obtains after the calcining is the CaS product.
Result of implementation:
It is 85% that CaS content 60% in the product, calcium sulfate are converted into the sulfurated lime transformation efficiency.
Embodiment 4
Raw material 1: used desulfurated plaster is with embodiment 3
Raw material 2: raw coal
The raw coal carbon content is 57.22%, and ash content is 21.94%, and volatilization is divided into 20%, and granularity is 5mm.
Implementation method:
Coal dust and desulfurated plaster are after the 1.5:1 ratio is mixed according to mass ratio, add circulating fluidized bed device by feeder, the circulating fluidized bed temperature remains on 900 ℃, material residence time in circulating fluidized bed is 1.5h, the tail gas that contains solid particulate separates through cyclonic separator, after the sack cleaner dedusting, by induced draft fan tail gas is sent into tail gas absorber, and by pipeline tail gas is returned fluidized-bed, it is 90% of tail gas amount that tail gas returns the amount of drawing, producing concentration is 5%～12%CO(volume percent) reducing gas, the product that obtains after the calcining is the CaS product.
Result of implementation:
It is 90% that CaS content 65% in the product, calcium sulfate are converted into the sulfurated lime transformation efficiency.
Claims (7)
1. a fluidization bed reducing and decomposing phosphogypsum prepares the method for sulfurated lime, it is characterized in that, coal dust and phosphogypsum are mixed, the mass ratio of proportioning is coal dust: phosphogypsum=0.5～3:1, used coal dust is that the mass percent of carbon content is 65%～80%, coal powder size is 0.75-8mm, after mixing, join in the circulating fluidized bed, temperature of reaction is 800～950 ℃, the tail gas that contains solid particulate separates through cyclonic separator, after the sack cleaner dedusting, by induced draft fan tail gas is sent into tail gas absorber, and by pipeline tail gas is returned fluidized-bed, returning the living concentration of induced labor by tail gas is 5%～12%CO reducing gas, obtains the CaS product behind the Cycle-decomposition.
2. fluidization bed reducing and decomposing phosphogypsum according to claim 1 prepares the method for sulfurated lime, it is characterized in that, the ash oontent mass percent of coal dust is 15%～50%, and the volatile content mass percent is 15%～30%, and coal powder size is 0.75-8mm.
3. fluidization bed reducing and decomposing phosphogypsum according to claim 1 prepares the method for sulfurated lime, it is characterized in that, the described phosphogypsum of step a refers to semi-hydrated gypsum, desulfurated plaster.
4. fluidization bed reducing and decomposing phosphogypsum according to claim 1 prepares the method for sulfurated lime, it is characterized in that, returns in the tail gas CO concentration 5%～12%.
5. fluidization bed reducing and decomposing phosphogypsum according to claim 1 prepares the method for sulfurated lime, it is characterized in that reactor refers to circulating fluidized bed device.
6. fluidization bed reducing and decomposing phosphogypsum according to claim 1 prepares the method for sulfurated lime, it is characterized in that, tail gas returns the 30%-100% that the amount of drawing is the tail gas amount.
7. fluidization bed reducing and decomposing phosphogypsum according to claim 1 prepares the method for sulfurated lime, it is characterized in that, decomposed tail gas partially or completely returns and draws, and as a part of fluidized wind, reduces O in the fluidized wind
2Content increases CO
2Content.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105858620A (en) * | 2016-05-20 | 2016-08-17 | 四川大学 | Method for decomposing gypsum through synergistic fluidization |
| CN105854739A (en) * | 2016-05-20 | 2016-08-17 | 四川大学 | Classified fluidized reactor in multi-component particle system bed and classified fluidized reaction method of classified fluidized reactor |
| CN111566051A (en) * | 2017-11-22 | 2020-08-21 | Ocp有限公司 | Phosphogypsum decomposition method |
| CN115504495A (en) * | 2022-10-21 | 2022-12-23 | 华新水泥股份有限公司 | Method for decomposing phosphogypsum by recycling tail gas |
| CN116425123A (en) * | 2023-04-13 | 2023-07-14 | 中国科学院过程工程研究所 | Device system and method for preparing calcium sulfide by utilizing industrial byproduct gypsum |
| CN116590022A (en) * | 2023-04-25 | 2023-08-15 | 湖北三峡实验室 | Method for producing acid soil conditioner by using phosphogypsum and pyrite |
| RU2814843C1 (en) * | 2023-07-11 | 2024-03-05 | федеральное государственное бюджетное образовательное учреждение высшего образования "Южно-Российский государственный политехнический университет (НПИ) имени М.И. Платова" | Method of producing calcium sulphide from phosphogypsum |
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| CN101239706A (en) * | 2008-03-17 | 2008-08-13 | 云南云天化国际化工股份有限公司 | Method for producing calcium sulfide from calcium sulfate |
| CN201161187Y (en) * | 2008-01-08 | 2008-12-10 | 上海大学 | Composite cycle fluidized bed apparatus for phosphogypsum decomposition |
| CN102502524A (en) * | 2011-10-28 | 2012-06-20 | 云南云天化国际化工股份有限公司 | Method for producing sulfur dioxide from calcium sulfate and sulfur |
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Patent Citations (5)
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105858620A (en) * | 2016-05-20 | 2016-08-17 | 四川大学 | Method for decomposing gypsum through synergistic fluidization |
| CN105854739A (en) * | 2016-05-20 | 2016-08-17 | 四川大学 | Classified fluidized reactor in multi-component particle system bed and classified fluidized reaction method of classified fluidized reactor |
| CN105854739B (en) * | 2016-05-20 | 2018-08-31 | 四川大学 | Multi component particle system bed internal classification fluidized reactor and its classification fluidisation reaction method |
| CN111566051A (en) * | 2017-11-22 | 2020-08-21 | Ocp有限公司 | Phosphogypsum decomposition method |
| CN115504495A (en) * | 2022-10-21 | 2022-12-23 | 华新水泥股份有限公司 | Method for decomposing phosphogypsum by recycling tail gas |
| CN116425123A (en) * | 2023-04-13 | 2023-07-14 | 中国科学院过程工程研究所 | Device system and method for preparing calcium sulfide by utilizing industrial byproduct gypsum |
| CN116425123B (en) * | 2023-04-13 | 2024-09-20 | 中国科学院过程工程研究所 | Device system and method for preparing calcium sulfide by utilizing industrial byproduct gypsum |
| CN116590022A (en) * | 2023-04-25 | 2023-08-15 | 湖北三峡实验室 | Method for producing acid soil conditioner by using phosphogypsum and pyrite |
| RU2814843C1 (en) * | 2023-07-11 | 2024-03-05 | федеральное государственное бюджетное образовательное учреждение высшего образования "Южно-Российский государственный политехнический университет (НПИ) имени М.И. Платова" | Method of producing calcium sulphide from phosphogypsum |
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