CN103172288B - Phosphogypsum pretreatment method - Google Patents
Phosphogypsum pretreatment method Download PDFInfo
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- CN103172288B CN103172288B CN201310071784.2A CN201310071784A CN103172288B CN 103172288 B CN103172288 B CN 103172288B CN 201310071784 A CN201310071784 A CN 201310071784A CN 103172288 B CN103172288 B CN 103172288B
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Abstract
The invention relates to a phosphogypsum pretreatment method. The method is characterized in that the method comprises the following steps: mixing 50-90% urea with phosphogypsum according to a molar ratio of 50-90% urea to calcium sulfate in phosphogypsum of 1.5-3:1, adding water having a weight being 10% of the weight of the above raw materials, reacting at 20-100DEG C for 0.5-6h, carrying out solid-liquid separation to obtain a solid pretreated phosphogypsum and a liquid phase, carrying out evaporating crystallization of the liquid phase to obtain urea crystals, recycling the urea crystals, and partially discharging and partially recycling the obtained evaporated water. The phosphogypsum pretreatment method has a simple treatment process, and makes waste phosphogypsum be changed to a qualified raw material for preparing other industrial and agricultural products through the above treatment.
Description
Technical field
The present invention relates to a kind of pretreatment process of phosphogypsum, belong to phosphorous chemical industry field.This pretreatment process is mainly used in purification and the utilization of phosphorous chemical industry waste ardealite.
Background technology
Phosphogypsum is a kind of solid waste produced in wet process phosphatic fertilizer production process, mainly containing gypsum, phosphorus, fluorine, silicon-dioxide and a certain amount of moisture, in stacking process, easily causes environmental pollution.The phosphogypsum that China discharges every year has nearly more than 2,000 ten thousand tons, store up over the years more than 100,000,000 tons.At present, have a lot to phosphogypsum Utilization plan, as building materials, produce ammonium sulfate etc., but due to phosphogypsum distribution comparatively concentrated, the sale radius of its product is little, makes the industry size that utilizes little.
Utilize phosphogypsum can the magnesium salts of production high added value, have bibliographical information activated magnesia can generate heavy magnesium water after carbonization, then utilize heavy magnesium water and gypsum to react and prepare magnesium sulfate.Plaster of paris purity is very high, foreign ion is few, and containing the detrimental impurity such as phosphorus, fluorine in phosphogypsum, part is even present in the lattice of phosphogypsum, bring huge difficulty to the purification of phosphogypsum, phosphogypsum is directly used in the production of magnesium sulfate, can to the following process of magnesium sulfate product, production as high-purity magnesium oxide brings impact, therefore first should carry out pre-treatment to phosphogypsum.
Carrying out pretreated method to phosphogypsum at present mainly contains several as follows:
1, WATER-WASHING METHOD (Duan Fugang, Wang Shaoting. improve the measure [J] of phosphogypsum Washing ratio. phosphate fertilizer and compound fertilizer, 1996,11 (3): 34-38; Zhang Ruquan, Wei Yanqing. phosphogypsum comprehensive treatment technique and conceptual design [J]. chemical fertilizer designs, and 2010,48 (3): 18-21; Recklessly establish an army. the test of phosphogypsum water washing cleaning and technique [J]. phosphate fertilizer and compound fertilizer, 2007,22 (5): 66-67).The main drawback of washing is that production line is once invested greatly, and energy consumption is high, and after washing, sewage discharge causes secondary pollution.2, ball milled (Wang Zhaoli, Gao Qian, Zhao Tiejun. the modification [J] of plaster of Paris and phosphogypsum. total utilization of PCA, 2001,4:42-43).Ball-milling processing does not disappear deimpurity disadvantageous effect, if can be better in conjunction with effect with other pretreatment technology.But technique is more complicated with the use of making, and investment increases.3, ageing method (Xie Chaoling, high Huimin, Zhu Fang. phosphogypsum pre-treatment and utilization [J]. Yunnan chemical, 2006,33 (2): 64-67).Its main drawback is the environment of meeting to surrounding in the process of ageing.4, dodge burning method (Duan Qingkui, Wang Liming. dodge the novel technique for harmless treatment of burning method-phosphogypsum. Ningxia petrochemical complex, 2004,3:13-16).Less by the treatment capacity of this method to phosphogypsum at present.5, wet screening eddy flow technique (Manjit Singh. Improved process for the purification of phosphogypsum. [J]. Construction and BuildingMaterials, 1996,10 (8): 597-600).
Other pretreated methods also comprise: carry out purifying treatment (Yang Ronghua with bicarbonate of ammonia and ammoniacal liquor and industrial by-product hydrochloric acid to phosphogypsum, Song Xigao. the purifying treatment of phosphogypsum and prepare the research [J] of calcium sulfate crystal whiskers. inorganic chemicals industry, 2004, 4:31-34), with add lime microwave method process phosphogypsum and carry out calcining produce plaster of Paris (Hu Xudong. the applied research of microwave technology in Phosphorus in Yunnan Province gypsum purification process process. Kunming University of Science and Technology's Master's thesis, 2006) and limestone vegetation modification method, floatation process process and Cerphos purifying process etc.
Urea is a kind of high density nitrogenous fertilizer, belongs to neutral readily avaiable fertilizer, also can be used for producing multiple compound manure.It is the product after animal protein metabolism, also can be obtained by synthetic.The solubleness of gypsum in urea soln that in experimenting, we find out that is comparatively large, can carry out recrystallization in urea soln to gypsum.Urea is used for the pretreated technical scheme of phosphogypsum, and there is not been reported.
Summary of the invention
The object of this invention is to provide a kind of pretreatment process of phosphogypsum, phosphogypsum generation recrystallization can be made by the method processing, make the further refinement of the granularity of phosphogypsum, the foreign ion in release lattice, thus meet the needs of subsequent product production.
Realize technical purpose of the present invention by following technical scheme, process flow sheet of the present invention is shown in accompanying drawing 1.
The pretreatment process of phosphogypsum of the present invention, comprises the following steps:
A. proportionally take urea, phosphogypsum, in urea and phosphogypsum, the mol ratio of calcium sulfate is 1.5-3:1;
B. pour the raw material described in step a into stirrer, add the water of raw material weight 10%, under 20-100 DEG C of condition, react 0.5-6 hour.
C. by step b gained reaction mixture solid-liquid separation, wherein solid is pretreated phosphogypsum;
D. gained solution evaporation crystallization after step c separation of phosphogypsum is obtained urea crystal, crystal recycles.
2, according to a kind of phosphogypsum pretreatment process according to claim 1, it is characterized in that, the concentration of urea is 50% ~ 90%.，
3, according to a kind of phosphogypsum pretreatment process according to claim 1, it is characterized in that, in described urea and phosphogypsum, the mol ratio of calcium sulfate is 1.5-3:1.
4, according to a kind of phosphogypsum pretreatment process according to claim 1, it is characterized in that, described water is the tap water meeting national drinking water sanitary standard.
Beneficial effect of the present invention is: phosphogypsum is after pre-treatment, and recrystallization occurs, and the further refinement of granularity, the impurity be wrapped in phosphogypsum crystal is released, and is conducive to the following process of phosphogypsum.
Accompanying drawing explanation
Fig. 1 is process flow sheet of the present invention.
Fig. 2 is the SEM figure of phosphogypsum after pre-treatment.
Embodiment
below in conjunction with drawings and Examples, the present invention will be further described in detail.
Embodiment 1
Urea and phosphogypsum are mixed in proportion, add the water of raw material weight 10%, then solid-liquid separation, gained solid is pretreated phosphogypsum, and gained liquid phase evaporative crystallization obtains urea crystal, and urea crystal recycles, gained vaporize water partial discharge, component loops uses.
Described urea concentration is 50%.
Described water is the tap water meeting national drinking water sanitary standard.
A pretreatment process for phosphogypsum, step is as follows:
1) proportionally take urea, phosphogypsum, in urea and phosphogypsum, the mol ratio of calcium sulfate is 1.5:1;
2) by 1) described in raw material pour stirrer into, add the water of raw material weight 10%, under 20 DEG C of conditions react 0.5 hour;
3) by 2) gained reaction mixture solid-liquid separation, wherein solid is pretreated phosphogypsum;
4) by 3) after separation of phosphogypsum the crystallization of gained solution evaporation obtain urea crystal, crystal recycles.
Accompanying drawing 2 is the SEM(scanning electron microscope of phosphogypsum after pre-treatment) picture, through measuring, the median size of phosphogypsum is about 50 microns, and the impurity of its parcel greatly reduces.
Embodiment 2
Urea and phosphogypsum are mixed in proportion, add the water of raw material weight 10%, then solid-liquid separation, gained solid is pretreated phosphogypsum, and gained liquid phase evaporative crystallization obtains urea crystal, and urea crystal recycles, gained vaporize water partial discharge, component loops uses.
Described urea concentration is 90%.
Described water is the tap water meeting national drinking water sanitary standard.
A pretreatment process for phosphogypsum, step is as follows:
1) proportionally take urea, phosphogypsum, in urea and phosphogypsum, the mol ratio of calcium sulfate is 3:1;
2) by 1) described in raw material pour stirrer into, add the water of raw material weight 10%, under 100 DEG C of conditions react 6 hours;
3) by 2) gained reaction mixture solid-liquid separation, wherein solid is pretreated phosphogypsum;
4) by 3) after separation of phosphogypsum the crystallization of gained solution evaporation obtain urea crystal, crystal recycles.
Embodiment 3
Urea and phosphogypsum are mixed in proportion, add the water of raw material weight 10%, then solid-liquid separation, gained solid is pretreated phosphogypsum, and gained liquid phase evaporative crystallization obtains urea crystal, and urea crystal recycles, gained vaporize water partial discharge, component loops uses.
Described urea concentration is 80%.
Described water is the tap water meeting national drinking water sanitary standard.
A pretreatment process for phosphogypsum, step is as follows:
1) proportionally take urea, phosphogypsum, in urea and phosphogypsum, the mol ratio of calcium sulfate is 2:1;
2) by 1) described in raw material pour stirrer into, add the water of raw material weight 10%, under 60 DEG C of conditions react 1 hour;
3) by 2) gained reaction mixture solid-liquid separation, wherein solid is pretreated phosphogypsum;
4) by 3) after separation of phosphogypsum the crystallization of gained solution evaporation obtain urea crystal, crystal recycles.
Embodiment 4
Urea and phosphogypsum are mixed in proportion, add the water of raw material weight 10%, then solid-liquid separation, gained solid is pretreated phosphogypsum, and gained liquid phase evaporative crystallization obtains urea crystal, and urea crystal recycles, gained vaporize water partial discharge, component loops uses.
Described urea concentration is 50% ~ 90%.
Described water is the tap water meeting national drinking water sanitary standard.
A pretreatment process for phosphogypsum, step is as follows:
1) proportionally take urea, phosphogypsum, in urea and phosphogypsum, the mol ratio of calcium sulfate is 1.5-3:1;
2) by 1) described in raw material pour stirrer into, add the water of raw material weight 10%, under 20-100 DEG C of condition, react 0.5-6 hour;
3) by 2) gained reaction mixture solid-liquid separation, wherein solid is pretreated phosphogypsum;
4) by 3) after separation of phosphogypsum the crystallization of gained solution evaporation obtain urea crystal, crystal recycles.
Claims (3)
1. a pretreatment process for phosphogypsum, is characterized in that, comprises the following steps:
A. proportionally take urea soln, phosphogypsum, in urea and phosphogypsum, the mol ratio of calcium sulfate is 1.5-3:1;
B. pour the raw material described in step a into stirrer, add the water of raw material weight 10%, under 20-100 DEG C of condition, react 0.5-6 hour;
C. by step b gained reaction mixture solid-liquid separation, wherein solid is pretreated phosphogypsum;
D. gained solution evaporation crystallization after step c separation of phosphogypsum is obtained urea crystal, crystal recycles.
2. according to a kind of phosphogypsum pretreatment process according to claim 1, it is characterized in that, the concentration of urea soln is 50% ~ 90%.
3. according to a kind of phosphogypsum pretreatment process according to claim 1, it is characterized in that, described water is the tap water meeting national drinking water sanitary standard.
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Inventor after: Fang Shixiang Inventor after: He Binbin Inventor after: Li Xiaoshuang Inventor after: Zhang Hui Inventor after: Wang Canxia Inventor after: Wang Menglai Inventor before: Fang Shixiang Inventor before: Zhang Yong Inventor before: Li Xiaoshuang |
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Free format text: CORRECT: INVENTOR; FROM: FANG SHIXIANG ZHANG YONG LI XIAOSHUANG TO: FANG SHIXIANG HE BINBIN LI XIAOSHUANG ZHANG HUI WANG CANXIA WANG MENGLAI |