CN101559966A - Calcium nitrate - Google Patents
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- CN101559966A CN101559966A CNA2009101351907A CN200910135190A CN101559966A CN 101559966 A CN101559966 A CN 101559966A CN A2009101351907 A CNA2009101351907 A CN A2009101351907A CN 200910135190 A CN200910135190 A CN 200910135190A CN 101559966 A CN101559966 A CN 101559966A
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Abstract
The invention relates to calcium nitrate solution or a method for purifying calcium nitrate smelt, and the calcium nitrate solution/smelt prepared by the method.
Description
Invention field
The present invention relates to the purification process of nitrocalcite CN solution/melts.
Background of invention
In nitrophosphate fertilizer (nitrophosphate) technology, rock phosphate is dissolved in the excessive nitric acid, make Digestive system be cooled to about 0 ℃, separate out four water-calcium nitrate.
The acidic precipitation thing is removed by centrifugal, neutralizes with ammoniacal liquor again.Granulation (granulation) or granulate (prilling) adjust moisture through evaporation before.
The rock phosphate ore, for example phosphatic rock contains high concentration ion, as Si
2+, Fe
2+, Fe
3+, Al
3+, F
-Deng, and calcium and phosphorus.Therefore be derived from the nitrocalcite crystal of digestion rock phosphate, comprise fluorochemical, phosphoric acid salt and silicate impurity that quantity does not wait.The grains of sand, silicate and sludge that digestion phase produces also may exist.Must remove the nitrocalcite that most of impurity could obtain to be applicable to technology application or drip-irrigation system.
Present purification process: the production phase of CN as shown in Figure 1 in the nitrophosphate fertilizer technology.Stage 5 to 7 is carried out the purifying of CN, comprises that dilute with water CN melts to density is 1,45 to 1,48 kg/liter under 60 ℃, is neutralized to pH 5 to 8 with ammoniacal liquor again.
Neutralization produces the precipitation of inorganic components, as phosphatic rock, Calcium Fluoride (Fluorspan), silicate and silica etc.
In order to reduce the amount of insoluble composition, the solution in stage 5 is mixed with flocculation agent.Form throw out, again by using settling centrifuge to remove most of inorganic substance.
Supernatant liquor is transferred to the stage 8, adjusts moisture here and forms the melts that contains 77% nitrocalcite CaN, 7% ammonium nitrate AN and 15% water.
The result of granulation or granulation produces solid product (solid CN), contains the insolubles of 2400 to 900 ppm.Insolubles is an insoluble compound, for example the mixture of silica, phosphatic rock, Calcium Fluoride (Fluorspan), Al-Fe-silicate etc.
These purifying rules are clearly formulated and the technology easy handling.Yet above-mentioned purifying process also has some shortcoming and defect.This purification process need add a large amount of water so that density is reduced to about 1,45 (70 ℃) from about 1,6 (70 ℃).These water must be removed through evaporation before granulation/granulation then, therefore needed a large amount of extra energy expenditures.In addition, 2400 to 900ppm level of purification is used also not enough for some technology.On market, greenhouse, the insolubles of this level can produce a large amount of precipitations in the past along with the time in storage tank, thereby needs the rules of cleaning equipment.At last, described arts demand is operated several settling centrifuges, and its maintenance cost is very expensive.
Other purification technique: the filter plant (for example candle-shaped filter) by press filtration (plate and frame) or other type carries out purifying, is all perception methods that salts solution are purified to high level of purity.Yet for the application of purifying nitrocalcite from phosphatic rock, these filtering systems can need to use flocculating aids (that is, diatomite), can accept to keep the flow that passes filter cake.The flocculating aids consumption has limited this equipment can only be used for less turnout, because the treatment process of filter cake must be suitable to environment, thereby has produced high cost.The operation of most strainers also is to be undertaken by criticizing, and this is the shortcoming with respect to continuous processing.Another shortcoming is must be with CN solution dilution to be purified to being lower than 1.5 kg/liter, to obtain acceptable viscosity and filtration velocity.This has just increased cost again, just can obtain solid CN material because all water of adding all must be removed.
Also has other purification process, for example by using porcelain filter and disk centrifugal separator to carry out micro-filtration.The micro-filtration method needs a large amount of investments.
In addition, the disk centrifugal chance in the test produces too many dirt, causes equipment to stop up.
RU 2228906 (summary) discloses the method for a kind of refining nitrocalcite melts or solution, separate the four water-calcium nitrate crystal by cooling phosphate ore nitric acid extraction thing, make crystal melting, with 0.5 to 60% ammonium nitrate solution dilution nitrocalcite melts/solution, with ammoniacal liquor dilute solution is neutralized to pH 6.1 to 7.6 again, the suspension by a step sedimentation gained in settling vessel comes separate solid impurity then.
RU 2154045 discloses a kind of method for preparing compound mineral fertilizer, wherein at 850 to 1050 ℃ of following incinerating phosphatic rock, decompose with non--cone nitric acid, the suspension that decomposition is obtained is added in the water, the amount that adds is every volume suspension 0.5 to 2.5 volume, remove undissolved residue by making the undissolved residue sedimentation, remove part nitrocalcite by cooling, make the solution ammonification, and obtaining the fertilizer of NP or NPK type through evaporation, granulation and drying treatment, the water of adding was removed through evaporation before the nitrocalcite crystallization.The process quilt of sedimentation insoluble precipitate has quickened manyfold, and stdn fertilizer is made by phosphite.
JP 2006225175 relates to a kind of production method that contains magnesium nitrate and nitrocalcite as the transparent liquid fertilizer of main component, wherein nitric acid is added in the water that contains rhombspar, stir simultaneously and mixing water, so that obtain magnesium nitrate and nitrocalcite after the neutralization, then, add and be selected from following at least a composition: the composition that can become the potassium composition, can become the compound of nitrogen component and the compound that can become micro-composition, make dissolving, add polymeric flocculant afterwards, and under 40 to 80 ℃ temperature condition, mix, make the mixture standing sedimentation, separate undissolved part.
The accompanying drawing summary
Fig. 1 is illustrated as the CN production phase of nitrophosphate fertilizer (nitrophosphate) technology.
Fig. 2 is the pilot plant by sedimentation continuous purification CN melts/solution.
Fig. 3 is the embodiment of thin slice equipment (Lamella equipment).
Fig. 4 is the cross section of pilot plant, that is, and and thin slice unit (Lamella unit) and the cross section that connects.
Fig. 5 is the content of water-insoluble in the pure melts that comes out from the slice separates device, what this depended on the density of melts (under 60 to 70 ℃, comprising flocculation agent) and melts gives materials flow (feed flow).
Fig. 6 is the amount of water-insoluble from the CN solution that the thin slice unit comes out, and mol P/mol F ratio in the interior CN crude product of 3 day time.
Fig. 7 is illustrated as the purifying of the CN that comes from nitrophosphate fertilizer technology.
Summary of the invention
An object of the present invention is to provide the purification process of improved CN solution/melts, that is, and CN solution/melts that present method provides the water-insoluble amount to reduce.
Another object of the present invention is the energy expenditure that reduces the CN purification phase.
The invention provides the purification process of the CN solution that comes from nitrophosphate fertilizer technology, comprise the step of sedimentation insolubles.Insolubles partly comes from the rock phosphate of digestion, and also part comes from the neutralization to the thick CN solution of acidity.
Sedimentation can be carried out in being suitable for any equipment of this purpose, particularly contains the jar of thin plate (plate) or thin slice (lamella).
The present invention provides the purification process of CN solution especially, and this method is adjusted mol P/mol F ratio to 0.4 by other phosphorus source of using phosphoric acid or dissolving in acid CN solution and carried out sedimentation after above.
Detailed Description Of The Invention
The invention provides the purification process of ca nitrate soln or melts, comprising settled step.After the precipitation step, centrifugal sludge phase.In addition, this method comprise by be back to digestion rock phosphate step with sludge recirculation.
Method of the present invention may further comprise the steps:
A) digestion rock phosphate,
B) cooling/crystallization,
C) filter,
D) washing crystal,
E) dissolving and be diluted to 1.3 to 1.75 kg/liter under 20 to 90 ℃ of temperature,
F) neutralization,
G) add flocculation agent and adjust mol P/mol F ratio,
H) sedimentation,
I) centrifugal sludge mutually and may the recirculation sludge to step a),
J) evaporation,
K) granulation (particulation).
In the embodiment of present method, above-mentioned steps e) is included under 70 ℃ and melts is diluted to about 1.6 kg/liter.
In another embodiment of present method, at above-mentioned steps g), adjust more than the mol P/molF to 0.30, preferred more than 0.45.
Being deposited in another embodiment of present method, step h) is furnished with thin plate, carry out in the slurry tank of thin slice.
In yet another embodiment of the present invention, provide insolubles content less than 3% ca nitrate soln/melts.
With the nitrocalcite of the inventive method production, by the known granulating method granulation in granulation, granulation or other any this area.
By X-ray diffraction analysis as can be known, the insolubles of separating out when the acid CN solution of neutralization is mainly by fluorapatite (fluoroapatite) (Ca
5(PO
4)
3F (70 to 95%) and a spot of SiO
2And CaF
2Form.The density of these mineral is 2.2 to 3.2 gram/cubic centimetres, therefore should sedimentation in the CN aqueous solution.We find that when the solution left standstill after the neutralization insolubles is understood slow sedimentation and formed the sludge phase in the bottom of container.
Settling velocity depends on factors such as the density of solution and mol P/mol F ratio.Usually solution is rare more, and settling velocity is fast more, and mol P/mol F ratio is low to cause settling velocity low.
The fast more fact of the rare more sedimentation of solution can directly be drawn by the Stokes law:
Vs＝K(ρins-ρsol)d
p 2/η
Wherein
Vs is a settling velocity
K is a constant
ρ ins is the density of insolubles
ρ sol is the density of solution
η is the viscosity of solution
d
p 2It is the particulate diameter
Second factor, mol P/mol F ratio is low to cause settling velocity low, and coming from the major impurity that N-process separates out is fluorapatite (Ca
5(PO
4)
3F) this fact.The desirable mol P/mol F ratio that described compound is separated out is 3.If ratio is low excessively, the phosphorite crystal of then separating out is few and little, that is, the crystalline growth velocity of phosphatic rock is low, and remaining F is as CaF
2Separate out, the sedimentation of all insolubles mixtures is obviously slower.Formed CaF
2And SiO
2Crystal is little, surface-area big and looser (fluffy).
Studies show that the low and mol P/mol F height (〉=0,7) of the F content in the CN solution can obtain the fast big phosphorite crystal of sedimentation.On the other hand, F concentration height and mol P/molF low (＜0,4), regular meeting produces the low small-crystalline of settling velocity.
As mentioned above, rock phosphate also comprises the F that quantity does not wait except that Ca and P, Si, Al, Fe and other kinds.Quantity can change with the type of rock phosphate and the difference of the applied washing rules of Fig. 1 step 4.
Therefore, enter the CN crystalline mol P/mol F of dilution and neutralization procedure, will change with the difference of used phosphoric acid salt crude product.
The typical rock phosphate of used some, Kola vitriol for example, Boucraa (Marocco) and Youssoufia (Marocco) or its mixture.Si, F, Fe, Al, Ca, the content of P etc. changes with type is different, and also can change in the same type.Therefore, come from the mol P/mol F in the CN solution of nitrophosphate fertilizer technology, intensity of variation also can be very big.In and in the process of CN melts, the denseness of the insolubles that forms and the amount of every kind of compound are understood difference, and can exert an influence to settling process.
In the continuous sedimentation process, before entering slurry tank, flocculation agent is added CN solution/melts.Add flocculation agent and can improve purifying, reduced the consumption of water-insoluble, the solids content of sludge increases, and that is to say to have obtained the more sludge of consolidation.In order to obtain better purifying, reduce the density of CN solution/melts, and increase mol P: mol F ratio.
Surprisingly, the amount that the amount of insolubles obtains far below the used purification process of present CN equipment (Fig. 1) in the solution behind the purifying wherein uses the whizzer that produces 500 to 2000g (centrifugal force) to remove insoluble particle.
Therefore, the purification process that comprises the sedimentation insolubles can be used for the CN in purifying nitrophosphate fertilizer (nitrophosphate) technology.
In order further to improve the purifying of CN solution/melts, can use the slurry tank of being furnished with metal sheet or thin slice.This precipitation apparatus is developed and is used for desalt.The batch can of giving that has the sedimentation unit of thin slice and CN solution/melts, for example, (step 6 Fig. 7) links to each other the neutralization tank of CN equipment.Before entering sedimentation unit, CN solution/melts is added flocculation agent and/or adjusts mol P/mol F ratio by optional.The sludge that sedimentation is obtained is discharged in the settling centrifuge, with the sludge phase dehydration.
The thin slice sedimentation unit is the jar of being furnished with the sheet metal (thin slice) of a lot being separated by about 0.05 to 0.1 meter basically.Thin plate inclination 40 to 70 degree.Thin slice has increased the total settlement area of jar, so sedimentation is more effective.Space between thin plate makes liquid upwards to move freely, and insoluble particle is blocked and be tending towards being deposited on the thin plate, and slips into downwards in the sludge jar of taper.
As mentioned above, before solution is transferred to slurry tank, optionally in CN solution/melts, add flocculation agent.The solution that adds flocculation agent at first is transferred to first mixing section, and flocculation agent and solution/melts carry out thorough mixing here.This chamber is furnished with revolving stirrer or other suitable mixing equipment.Solution/the melts that is mixed with flocculation agent overflows into has second Room of mobile agitator at a slow speed, makes the particle of the flocculation of formation keep suspended state.
Melts/solution flows into the thin slice slurry tank from second Room, enter in the bottom of thin plate.Solution is moving up between the thin plate and through placing the letdown tank above the thin plate to leave the slice separates device.Letdown tank has a lot of holes, and liquid must flow through these holes to leave thin slice.Letdown tank can guarantee that solution is evenly distributed on the thin plate like this.
Solid particles sediment is on thin plate and slip into downwards in the sludge bucket of being furnished with revolving scraper very at a slow speed.Make sludge level in the sludge bucket keep constant or, the sludge level in the sludge bucket is changed by sludge being pumped into mutually the settling centrifuge dehydration.
In an embodiment of the invention, provide the purification process of CN solution/melts in the nitrophosphate fertilizer technology, wherein purification step comprises the sedimentation insolubles and described insolubles is discharged from the slurry tank bottom.
In yet another embodiment of the present invention, provide the purification process of CN solution/melts in the nitrophosphate fertilizer technology, wherein purification step is included in sedimentation insolubles in the thin slice slurry tank.
In yet another embodiment of the present invention, enter before the slurry tank, flocculation agent is added into CN solution/melts.Can use various flocculation agent; Preferred flocculation agent is selected from Fennopol A3304, Nordfloc A172 and Superfloc AF126.
And in yet another embodiment of the present invention, the sludge by settled insolubles forms is discharged by the slurry tank bottom, and the further processing as centrifugal of optional experience.In extra centrifugation step, sludge further is separated into precipitation (being the concentrated granular of insolubles) and supernatant liquor (be purifying after melts).
The density of CN solution/melts to be purified is 1.3 to 1.75 kg/liter, and preferred 1.45 to 1.65 kg/liter, the temperature of solution/melts remain on 25 to 90 ℃, preferred 40 to 80 ℃.
Mol P/mol F is the feature of CN crude product melts, and can change by the rock phosphate of change NPK equipment or by add strong phosphoric acid in CN crude product melts.MolP/mol F can also dissolve in acidity by adding and slightly change in other phosphoric acid salt source of CN solution.The add-on of strong phosphoric acid can change according to the mol P/mol F in CN solution/melts, and but, the consumption of 0 to 9 kilograms per cubic meter CN solution is (based on 50%CaN in the solution) usually enough.
According to the purifying of the present invention, set forth as schematically shown in Figure 7 CN in the nitrophosphate fertilizer technology.
Purifying comprises extra step 8, carries out purifying by sedimentation.The optional adding flocculation agent that comprises of step 7, and add phosphoric acid or other phosphate source is adjusted mol P/mol F ratio.
To the modification of step 7, comprise and adjust mol P/mol F ratio, comprise the subsidence stage that contains the settling centrifuge that is used for sludge conditioning, obtained some advantage of comparing with technology shown in Figure 1.
One of these advantages are to have saved a large amount of energy, because the density of pending CN solution is up to 1.67.In existing purifying process, the CN melts (from the stage 4, Fig. 1) must be diluted to the density of about 1.47 kg/liter.In technology of the present invention, can omit dilution step usually.The insolubles concentration that the solid CN that subsidence stage obtains comprises is generally 350ppm.Compare with present technology, (obtaining insolubles content is the solid CN of 1000ppm) as shown in Figure 1, this is a substantial progress.
Consume energy identical in the technology shown in Figure 1, use technology of the present invention insolubles content can be reduced to 50 to 100ppm.
The maintenance cost of settling centrifuge can reduce greatly, because technology of the present invention is only used 1 little whizzer, and existing technology will be used 3 big whizzers.
To discuss the present invention by following unrestricted embodiment now.
Embodiment
Use other flocculant solution except as otherwise noted, Nordfloc A172 (being provided by SNF) all is provided in the enforcement of all embodiment.1 kilogram of flocculation agent of dissolving prepares flocculant solution in batches in 1 cubic metre of water in the flocculation jar.With 0.1% solution that obtains be added to thick melts and the sludge that enters settling centrifuge mutually in.
Embodiment 1
In laboratory inspection, will from the difference of equipment and CN solution (about 1000 milliliters) mix with flocculation agent, and be transferred in the graduated cylinder (1000 milliliters), left standstill 2 minutes.Observe the sludge phase, i.e. the volume of settled insolubles.The result is as shown in table 1 below:
S 1 and S2 represent the sample 1 and 2 from equipment.
Table 1 is neutralized to the CN solution of pH 6 to 7 (1+10) with ammoniacal liquor
| Solution density (gram/cubic centimetre) | The flocculation agent Superfloc (Cytec Ind) 1% that adds (milliliter/rise solution) | Sludge volume (milliliter) | ％P | ％F | mol P/mol F | The amount (ppm) of insolubles in the liquid on the sludge phase |
| 1.57(S1) | 6 | 330 | 0.15 | 0.12 | 0.77 | NA |
| 1.57(S1) | 6 | 350 | 0.15 | 0.12 | 0.77 | 80 |
| (1.49 S1+ water) | 6 | 190 | 0.15 | 0.12 | 0.77 | 72 |
| (1.49 S1+ water) | 6 | 180 | 0.15 | 0.12 | 0.77 | 68 |
| 1.55(S2) | 6 | 800 | 0.065 | 0.14 | 0.28 | 60 |
| (1.48 S2+ water) | 6 | 750 | 0.065 | 0.14 | 0.28 | 55 |
NA=does not have
Table 1 result is clear to be shown, if satisfied some precondition, the insolubles sedimentation can be suitable fast.But can draw to draw a conclusion: i) solution is rare more, and settling velocity is fast more; Ii) molP/molF ratio is low, settling velocity low and iii) on the sludge in the solution amount of insolubles very low.
Embodiment 2
The test of pilot plant
Embodiment 1 described test is a batch process.For further the check sedimentation is in order to obtain pure melts, that is, by the CN melts of the next effective purifying of sedimentation from nitrophosphate fertilizer technology, pilot plant designs as shown in Figure 2.The volume of pilot plant is about 1.5 cubic metres, makes by synthetic glass, but the visual observation sedimentation.
Equipment describe:
Jar A: thorough mixing flocculation agent and thick CN solution
Jar B: gentle mixed flocculation agent and thick CN solution
Volume D: the settling zone of the insoluble sludge of water
Volume C: pure CN solution
Thick CN solution is pumped into a jar A, carry out thorough mixing (super mixer, short residence time(SRT)) with suitable flocculation agent Nordfloc A172 here.Stirred solution 2 to 6 minutes gently in jar B then is so that bigger throw out is assembled.Solution spreads all over whole jar by action of gravity inflow region D and distribution, and slowly moving up enters zone C.
Throw out (insolubles) is receiving area D downwards, and the tapered section of jar is drained from the bottom again.Solution is depressed into the top and the wall that overflow from zone C, enters to pass outlet mouth " clean melts (clean melt) " after the drain chamber and leave.
Use has been carried out several tests from the equipment and CN solution (" KS smelte " among Fig. 2) under different condition.The result is as shown in table 2 below.
The result of table 2. pilot plant sedimentation purifying
| The density of thick CN solution, 1% insolubles | The pH of CN solution | ％P | ％F | mol P/ mol F | The residence time in slurry tank (minute) | Insolubles % in the sludge (degree of packing of sludge) | The ppm of flocculation agent | Add H 3PO 4 + Δmol P/F | The ppm of insolubles in the CN solution |
| 1630 | 6.2 | NA | NA | NA | 86 | 5.7 | 7.4 | NA | 484 |
| 1500 | 0.10 | 0.15 | 0.41 | 36 | 8.0 | 8.0 | |
250 | |
| 1500 | 6.1 | 0.50 | 36 | 10.6 | 8.0 | +0.1 | 189 | ||
| 1515 | 6.1 | 0.10 | 0.14 | 0.44 | 89 | NA | 8.3 | NA | 204 |
| 1535 | 6.1 | 0.13 | 0.14 | 0.57 | 89 | NA | 8.2 | |
150 |
| 1510 | 6.1 | NA | NA | 0.70 | 60 | 13.0 | 9.0 | +0.2 | 120 |
NA=does not have
Embodiment 3
In another embodiment, the pilot plant of Fig. 2 is by more advanced substituting for water purifies the precipitation apparatus of developing.Thin slice sedimentation unit (model LF is provided by Nordic Water) links to each other with the neutralization tank (stage 5 of Fig. 1) of CN equipment, and connects the settling centrifuge that is used for the sludge phase dehydration.
Generally speaking, the thin slice unit is very similar to the precipitation apparatus of Fig. 2, but the thin slice unit is furnished with several thin plates (thin slice), is mounted to each other at a distance of about 0.05 to 0.1 meter.Thin plate inclination 55 degree.The horizontal settling area of total protrusion is 5 square metres.Space between thin plate makes liquid freely to move up, and insoluble particle is blocked and be deposited on the thin plate, and slips into taper sludge zone downwards.
The pilot plant cross section that shows thin slice unit and connection, as shown in Figure 4.
There is individual flocculator upper left side in " thin slice unit ", and it is made up of two chambers, and cumulative volume is 1 cubic metre.The first Room volume is little and be furnished with the high speed rotating agitator, so that flocculation agent and melts thorough mixing.
Melts overflows into second Room with microrunning agitator, so that the flocculation particle that forms keeps suspended state.
Melts/solution flows into the thin slice jar from second Room, enter in the bottom of thin plate.Solution is moving up between the thin plate and through placing the letdown tank above the thin plate to leave the slice separates device.Letdown tank has a lot of holes, and liquid must flow through these holes to leave thin slice.Letdown tank can guarantee that solution is evenly distributed on the thin plate like this.
Solid particles sediment is on thin plate and slip into downwards in the sludge bucket of being furnished with revolving scraper very at a slow speed.Make sludge level in the sludge bucket keep constant or, the sludge level in the sludge bucket is changed by sludge being pumped into mutually the settling centrifuge dehydration.
The result that the residence time and thick CN solution density change as shown in Figure 5.Fig. 5 shows the amount leave water-insoluble in the unitary purifying CN of the thin slice melts, this depend on the density (, comprising flocculation agent) of melts and melts at 60 to 70 ℃ to materials flow.
These results show that the density of thick CN solution is low more, and the content that leaves insolubles in the unitary purification solution of thin slice is low more.When density was 1.58 to 1.60 kg/liter (70 ℃), the content of insolubles was usually less than 300ppm.When density is about 1.46 to 1.47 kg/liter, can obtain being lower than the insolubles content of 50ppm.
The residence time changed between 60 to 35 minutes, can not produce remarkably influenced to the purifying of CN solution.
Embodiment 4
The influence of the mol P/mol F ratio of thick CN solution
The thin slice sedimentation unit links to each other with CN equipment, carries out settling test for three days on end.The mol P/mol F ratio of CN crude product can change by the rock phosphate in the change NPK equipment with by add phosphoric acid in thick CN liquid.Measure the content of insolubles in the purifying CN solution.
Use following condition:
Flow velocity: 2.5 cubic metres of CN solution/hour
The residence time: 34 minutes
Flocculation agent consumption: 20ppm (0.1% solution)
Melts density: average out to 1580 kilograms per cubic meter, 80 ℃ (1550 to 1620)
The content of insolubles in the CN crude product: 1 to 1.6%
The pH:5.5 to 6.5 of thick CN solution
The flow velocity of sludge phase: 250 liters/hour
The result as shown in Figure 6.Show the content that leaves water-insoluble in the unitary CN solution of thin slice in 3 day time and the mol P/mol F ratio of CN crude product.
Fig. 6 shows that, water-insoluble reduced to 150 to 350ppm until May 23 at 1800 o'clock.The mol P/mol F ratio of this period is 0.4 to 0.5.
Since 1800 o'clock on the 23rd May, water-insoluble began to increase, and the mol P/mol F ratio of CN crude product drops to 0.3.From 24 days 0400 May, water-insoluble dropped to about 200ppm from about 1000ppm, and mol P/mol F ratio stably shifts to 0.7.
The development afterwards of water-insoluble was interrupted between 24 days 1200 to 1600 May, because the pH value has exceeded tolerance interval (more than 7, because HNO in the equipment
3Block).
When the molP/mol F ratio of the thick CN solution acid CN solution of NPK equipment (and from) reduced, the water-insoluble crystal that forms in neutralization stage became littler and looser.Thereby formed at sedimentation unit and to have occupied the bigger sludge of volume.This sludge sedimentation slowly many, the insolubles that leaves among the CN of thin slice increases.
Mol P/mol F ratio is the feature of CN crude product, can change by the rock phosphate of change NPK equipment or by adding strong phosphoric acid.
The processing of sludge phase:
Leave the unitary sludge of thin slice and link to each other, with the dry-matter of desludging in mutually with settling centrifuge.The g-power (g-force) of settling centrifuge is about 550.
Before entering whizzer, be added to 25 to 35ppm flocculation agent to sludge.
The concentrated sludge (thin slice feed about 15%) that leaves whizzer is recycled to digestion phase, that is, and the stage 1 of Fig. 1.
The CN solution (centrifugal feed about 85%) that leaves whizzer contains the insolubles that is less than 450ppm, mixes with the purifying CN stream that comes out from the thin slice unit, perhaps is recycled to enter during the unitary CN crude product of thin slice flows.
The result shows, be derived from nitrophosphate fertilizer technology and reach the thick CN solution of 1620 kilograms per cubic meter 70 ℃ of lower densities, can be purified by slurry tank and become to contain 200 to 300ppm insolubless, the slurry tank of preferred belt shape thin plate, condition is to reach 35 minutes the residence time, and the mol P/mol F ratio of CN solution is more than 0.4, and is preferred more than 0.5.
If mol P/mol F ratio is lower than 0.4, then the sludge settling velocity reduces, and purification efficiency reduces.Purifying still can carry out, but the required sludge stream that leaves slurry tank is much higher.
The variation of mol P/mol F ratio can be by adding strong phosphoric acid or dissolving in other phosphate source of acid thick CN solution and easily realize.
Claims (9)
1. the method for purifying ca nitrate soln or melts is characterized in that this method comprises precipitation step.
2. the method for claim 1 is characterized in that carrying out centrifugal mutually to sludge after the sedimentation.
3. claim 1 or 2 method is characterized in that sludge is back to the digestion step recirculation of rock phosphate.
4. claim 1,2 or 3 method is characterized in that this method may further comprise the steps:
A) digestion rock phosphate,
B) cooling/crystallization,
C) filter,
D) washing crystal,
E) dissolving and be diluted to 1.3 to 1.75 kg/liter under 20 to 90 ℃ of temperature,
F) neutralization,
G) add flocculation agent and adjust mol P/mol F ratio,
H) sedimentation,
I) centrifugal sludge phase and possibility recirculation sludge are to step a)
J) evaporation
K) granulation.
5. the method for claim 4, it is characterized in that: in the step e), melts is diluted to about 1.6 kg/liter under 70 ℃.
6. claim 4 or 5 method is characterized in that: in step g), adjust more than the molP/mol F to 0.30, and preferred more than 0.45.
7. claim 4,5 or 6 method is characterized in that: step h) be deposited in the slurry tank of being furnished with thin plate, carry out in the thin slice slurry tank.
8. ca nitrate soln/melts, it is characterized in that: it comprises and is less than 3% insolubles.
9. ca nitrate soln/the melts of claim 8 is characterized in that: it is according to the method preparation of claim 1 to 7.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20081853 | 2008-04-16 | ||
| NO20081853A NO332615B1 (en) | 2008-04-16 | 2008-04-16 | Method of purifying calcium nitrate solutions or melts |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410338685.0A Division CN104085910A (en) | 2008-04-16 | 2009-04-15 | Calcium nitrate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101559966A true CN101559966A (en) | 2009-10-21 |
Family
ID=41218972
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410338685.0A Pending CN104085910A (en) | 2008-04-16 | 2009-04-15 | Calcium nitrate |
| CNA2009101351907A Pending CN101559966A (en) | 2008-04-16 | 2009-04-15 | Calcium nitrate |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410338685.0A Pending CN104085910A (en) | 2008-04-16 | 2009-04-15 | Calcium nitrate |
Country Status (7)
| Country | Link |
|---|---|
| CN (2) | CN104085910A (en) |
| CO (1) | CO6210122A1 (en) |
| CZ (1) | CZ2009222A3 (en) |
| NO (1) | NO332615B1 (en) |
| PL (1) | PL220612B1 (en) |
| RU (1) | RU2414426C2 (en) |
| ZA (1) | ZA200901756B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2507154C1 (en) * | 2012-08-14 | 2014-02-20 | Открытое Акционерное Общество "Завод минеральных удобрений Кирово-Чепецкого химического комбината" (ОАО "ЗМУ КЧХК") | Method of obtaining purified solution of calcium nitrate |
| CN106629805A (en) * | 2016-10-17 | 2017-05-10 | 交城县三喜化工有限公司 | Method and device for producing calcium nitrate liquid |
-
2008
- 2008-04-16 NO NO20081853A patent/NO332615B1/en not_active IP Right Cessation
-
2009
- 2009-03-11 ZA ZA2009/01756A patent/ZA200901756B/en unknown
- 2009-04-06 RU RU2009112498/05A patent/RU2414426C2/en active
- 2009-04-09 CZ CZ20090222A patent/CZ2009222A3/en unknown
- 2009-04-15 CN CN201410338685.0A patent/CN104085910A/en active Pending
- 2009-04-15 CN CNA2009101351907A patent/CN101559966A/en active Pending
- 2009-04-16 CO CO09038652A patent/CO6210122A1/en active IP Right Grant
- 2009-04-16 PL PL387815A patent/PL220612B1/en unknown
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2507154C1 (en) * | 2012-08-14 | 2014-02-20 | Открытое Акционерное Общество "Завод минеральных удобрений Кирово-Чепецкого химического комбината" (ОАО "ЗМУ КЧХК") | Method of obtaining purified solution of calcium nitrate |
| CN106629805A (en) * | 2016-10-17 | 2017-05-10 | 交城县三喜化工有限公司 | Method and device for producing calcium nitrate liquid |
| CN106629805B (en) * | 2016-10-17 | 2017-11-21 | 交城县三喜化工有限公司 | A kind of method and its device for producing calcium nitrate liquid |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA200901756B (en) | 2010-02-24 |
| NO332615B1 (en) | 2012-11-19 |
| CZ2009222A3 (en) | 2010-08-11 |
| PL387815A1 (en) | 2009-10-26 |
| NO20081853L (en) | 2009-10-19 |
| CO6210122A1 (en) | 2010-10-20 |
| RU2009112498A (en) | 2010-10-20 |
| RU2414426C2 (en) | 2011-03-20 |
| CN104085910A (en) | 2014-10-08 |
| PL220612B1 (en) | 2015-11-30 |
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Application publication date: 20091021 |