The compound pretreatment technology of phosphogypsum
Technical field
The present invention relates to renewable resource environmental technology field, the compound pretreatment technology of especially a kind of phosphogypsum.
Background technology
Phosphogypsum is the industrial residue of phosphoric acid or Phosphate Fertilizer Industry and the discharge of some synthetic detergent industry, and main component is terra alba (CaSO
42H
2o), but also contain undecomposed phosphorus ore, multiple being detrimental to health and biological growth such as phosphoric acid, Calcium Fluoride (Fluorspan), Sodium Fluoride, iron aluminide, sour insoluble organic matter and shale foreign material of washes clean not, and affect the impurity of plastering quality.Wherein, titanium pigment makes prolongation time of coagulation, the strength decreased of semi-hydrated gypsum; The solvable fluorine existing with NaF form can make hydrated product dihydrate gypsum crystal extensive, and between crystal, conjugation reduces, and structural capacity weakens; Organism increases plaster of Paris surface denseness, needs water consumption to increase when cementing, and extend time of coagulation, and weaken the joint of dihydrate gypsum crystal, makes hardenite loosely organized, strength decreased; Potassium, sodium salt can make plastering surface occur hydrochloric acid, and be easy to entered environment attached containing when sour water is stacked, and water body and soil are produced to detrimentally affect.In general, the phosphogypsum solid impurity content of chemical enterprise emission is more than 10%, and total phosphorus reaches 1.5%-2%, pH value 1-2, SO
3content is lower than 35%, containing sour water 30 left and right, terra alba total amount is less than 70%, and containing a small amount of organism, phosphate anion, sulfate ion, affect plastering, particularly discharge is stored up and is shown over the ground water, underground water, plant growth, human settlement and can produce very big harm.If do not processed any row's heap, not only take a large amount of soils, and the seepage of sour water is, the loss of fluorine and some radioelement very easily cause environmental pollution, also hindered the comprehensive utilization of phosphogypsum, only remove or reduce the detrimental impurity in phosphogypsum, just can become available secondary resource.Therefore, must carry out pre-treatment to phosphogypsum, significantly to improve phosphogypsum utilization ratio, to turn waste into wealth, thereby realization is protected ecology, is benefited the society.
Phosphogypsum being carried out to pre-treatment both at home and abroad at present has physics, chemistry and physico-chemical process, include WATER-WASHING METHOD, neutralisation, staging, wet screening vortex method, dodge and water method, flotation process, ball milled etc., but they respectively has relative merits.Although water washing cleaning treatment process can be removed a large amount of impurity and organism, water loss great Yi causes secondary pollution, and the easy industry scale formation of sewage treatment equipment.In and modification method to P in phosphogypsum
2o
5impact significantly, still limited to other impurity effect, and cost is higher.Cerphos purifying process (staging) is mainly processed the impurity of footpath grain between 16um-25um, and wet screening eddy flow rule is mainly dissolved the phosphoric acid salt of granularity in the phosphogypsum of 10-15um and the organism of enrichment and lattice.Sudden strain of a muscle is watered in method process and can be produced obnoxious flavour, flotation process to soluble impurity removal effect significantly and floatation equipment easily corrode, ball milling washing process owned by France, to the pre-treatment of phosphogypsum, mostly in ardealite storage yard feeding, now phosphogypsum is to environment.
In sum, the fewer quality of phosphogypsum impurity is better to be just more easily utilized, and therefore, is the matter of utmost importance that solves phosphogypsum comprehensive utilization to the purification pre-treatment of phosphogypsum.Yet, currently there is no good Pretreatment Technology of Phosphogypsum, thereby cause the utilization ratio of phosphogypsum extremely low.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of reasonable, advanced, economic compound pretreatment technology of phosphogypsum; to extract the phosphogypsum of the low impurity high-quality of high purity; thereby realize high-efficiency comprehensive utilization phosphogypsum, the object of can protection of the environment again can solid waste utilizing.
For solving the problems of the technologies described above, the present invention adopts following technical scheme: the compound pretreatment technology of phosphogypsum, directly from the slag-drip opening of chemical enterprise, get phosphogypsum slag, enter 30 order vibratory screening apparatus sortings, trade effluent with chemical enterprise rinses phosphogypsum slag simultaneously, rub into the purification process of washing and sorting, during screening, can remove the impurity such as hard mineral that 10% left and right particle diameter is thicker; In the phosphogypsum slurries that obtain after flushing, add the alkali matter that accounts for phosphogypsum quality 1%~2% to increase calcium liquid adjusting pH value to 7 ± 1, then send into layering filter tank stirring, standing, use method for floating to remove top layer organism film and soluble impurity, fully used neutralisation principle to change the pH value of phosphogypsum, can effectively avoid the erosion to treating plant simultaneously; The phosphogypsum slurries that layering is purified enter vacuum filter and carry out vacuum filtration, obtain filter residue and drainage.
Chemical enterprise is phosphoric acid, phosphate fertilizer or synthetic detergent manufacturing enterprise, as long as there is the enterprise of phosphogypsum discharge port can apply this technique.
Trade effluent is from the waste water of fertilizer plant's phosphorus ore ball milling or the generation of phosphoric acid washing process.
The carbide slag that alkali matter increasing calcium liquid is discharged by chemical enterprise production of caustic soda, the sugared slag that discharge in sugar refinery, the increasing calcium alkaline residue of paper mill discharge or lime dilution stirring form, and its pH value is 12~14, and the object adding is extremely neutral with the pH value of phosphogypsum in being.Belong to Industrial Solid Waste utilization, the method with respect to tradition with lime neutralizing treatment, the one, without dust pollution, do not produce obnoxious flavour, the 2nd, saved purification cost, more focused on economic benefit.
Filter residue is high purity phosphogypsum.
High purity phosphogypsum is moisture below 10%, pH value 7 ± 1, SO
3reach more than 43% CaSO
42H
2o content is more than 90%, and solvable phosphorus decomposing is below 0.01%, and total phosphorus is below 0.05%, and impurity is below 1%.
Hard dirt is directly used in concrete production, directly produces economic benefit.
Drainage flows back to chemical enterprise phosphorus ore ball mill by pipeline and recycles, and has guaranteed, in the situation that not forming water pollution, to have realized reclaiming again of available phosphorus, and effective utilization of water and the high efficiente callback of phosphorus have brought significant economic benefit.
The traditional method of chemical enterprise is directly phosphogypsum slag to be drained into slag dam to store up, now dust is scattered, the contamination phenomenon such as sour water seepage occurred, when phosphogypsum will be utilized, by slag dam, being transported to disposal field again purifies, processes, so repeatedly transportation has increased cost first, and the 2nd, destroyed environment.For this reason, the present invention directly gets phosphogypsum from chemical enterprise slag-drip opening, before phosphogypsum not yet pollutes ecotope, carries out compound pre-treatment, greatly reduces phosphogypsum and stores up the impact on ecotope.Contriver adopts physico-chemical process to purify to phosphogypsum slag, removed most of impurity or foreign matter content has been down to compared with low degree, obtained high purity phosphogypsum, can directly be transported to cement setting retarder and light gypsum walling production site is stored up, the hard dirt that sub-sieve extracts can be used for commerical ready-mixed concrete.Harmful solid waste and toxic gas are not discharged in the whole technical process of the present invention, stopped secondary pollution, solved the problem that phosphogypsum discharges arbitrarily land occupation, wastes sulphur resource, contaminate environment, harm ecology, guaranteed to take the quality of the derived product that high-quality phosphogypsum is raw material simultaneously, high purity phosphogypsum can be applicable to production higher-grade cement retarder from ardealite and α, β gypsum, realized the organic unity of environmental benefit, economic benefit, social benefit.
Accompanying drawing explanation
Fig. 1 is the schema of the compound pretreatment technology of phosphogypsum of the present invention.
Embodiment
Fig. 1 has shown the flow process of the compound pretreatment technology of phosphogypsum of the present invention, and wherein phosphogypsum is taken from the slag-drip opening of chemical enterprise technical process end, below in conjunction with embodiment, further illustrates the present invention.
Embodiment 1
Raw material sources
Phosphogypsum slag---Guangxi Luzhai chemical fertilizer company limited production discharge port, in phosphogypsum slag containing 30 left and right sour waters, 15% solid impurity, 35% SO
3, 70% CaSO
42H
2o, pH=2, particle is uneven, is grey black.
Trade effluent---waste water between certain fertilizer plant's phosphorus ore ball grinding vehicle.
Alkali matter increases calcium liquid---the slurries of the lime furnishing that periphery Lime Factory produces, pH value 12 left and right.
Technical process
Directly from the slag-drip opening of chemical enterprise, get phosphogypsum slag, enter 30 order vibratory screening apparatus sortings, with trade effluent, rinse phosphogypsum slag simultaneously, remove the hard dirt that 10% left and right particle diameter is thicker, in the phosphogypsum slurries that obtain after flushing, add the alkali matter that accounts for phosphogypsum quality 2% to increase calcium liquid adjusting pH value to 7 ± 1, then send into layering filter tank stirring, standing, remove top layer organism film and soluble impurity, the phosphogypsum slurries that layering is purified enter vacuum filter and carry out vacuum filtration, obtain filter residue and drainage.Filter residue is high purity phosphogypsum, and transportation is stored up.Drainage flows back to chemical enterprise phosphorus ore ball mill by pipeline and recycles.
Embodiment 2
Raw material sources
Phosphogypsum slag---with embodiment 1.
Trade effluent---certain fertilizer plant's phosphoric acid washing technical process waste water.
Alkali matter increases calcium liquid---and by the carbide slag dilution of chemical plant, Liuzhou production of caustic soda discharge, stirred and formed, its pH value is in 14 left and right.
Technical process
Add 1% alkali matter to increase calcium liquid and regulate pH value to 7 ± 1, other are with reference to embodiment 1.
Embodiment 3
Raw material sources
Phosphogypsum slag---with embodiment 1.
Trade effluent---waste water between certain fertilizer plant's phosphorus ore ball grinding vehicle.
Alkali matter increases calcium liquid---and by the increasing calcium alkaline residue dilution of Guangxi phoenix candy paper industry discharge, stirred and formed, its pH value is in 13 left and right.Technical process
Add 1.5% alkali matter to increase calcium liquid and regulate pH value to 7 ± 1, other are with reference to embodiment 1.
After testing, the high purity phosphogypsum of embodiment 1 to 3 is moisture below 10%, pH value 7 ± 1, SO
3reach more than 43% CaSO
42H
2o content is more than 90%, and solvable phosphorus decomposing is below 0.01%, and total phosphorus is below 0.05%, and impurity is below 1%, specifically in Table 1.
Component and the performance of table 1 embodiment 1 to 3 high purity phosphogypsum