CN101531369A - Method for removing porcelain by hydrofluoric acid and co-producing white carbon black - Google Patents
Method for removing porcelain by hydrofluoric acid and co-producing white carbon black Download PDFInfo
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- CN101531369A CN101531369A CN200910068620A CN200910068620A CN101531369A CN 101531369 A CN101531369 A CN 101531369A CN 200910068620 A CN200910068620 A CN 200910068620A CN 200910068620 A CN200910068620 A CN 200910068620A CN 101531369 A CN101531369 A CN 101531369A
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- silicon tetrafluoride
- hydrofluoric acid
- carbon black
- white carbon
- cast iron
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Abstract
The invention discloses a method for removing porcelain by hydrofluoric acid and co-producing white carbon black, comprising the following steps: (1) immersing cast iron enamel defective products in a reaction vessel with hydrofluoric acid water solution, carrying out the heating reaction, generating silicon tetrafluoride gas, filtering, re-inputting filtrate into the reaction vessel, washing other substances by sodium hydroxide water solution, recovering cast iron and further processing waste residues; (2) using ammonia water to simultaneously absorb the silicon tetrafluoride gas and hydrogen fluoride gas, using ammonium fluoride water solution to absorb the silicon tetrafluoride gas which is not absorbed and heating, thereby obtaining ammonium fluosilicate solution; (3) using ammonia water to regulate pH for reaction, generating sediment, filtering, separating, acidifying a filter cake by sulfuric acid, aging, filtering, washing by water and drying, thereby obtaining the white carbon black. The recovery rate can be more than 90 percent by using the method to process the cast iron enamels, and the method has the advantages of short reaction time, reasonable utilization of the acid, high utilization rate of raw materials and low production cost.
Description
Technical field
The present invention relates to a kind of method that removes the defective enamel coating of Cast Iron Surface and utilize product production white carbon black, particularly relate to a kind of method of removing porcelain by hydrofluoric acid and co-producing white carbon black.
Background technology
Enamel preparation technology comprises a lot of operations, and the quality of enamel layer depends on several factors, even can not avoid defect ware occurring in the enamel production just defective enamelware fully to each strict control of production workshop section.For these defect wares, remove the enamel application of slip again on enamel blank surface fully.
The porcelain that takes off for enamel product is handled usually mechanical means processing such as employing sandblast, ball blast and principle of expanding with heat and contracting with cold.Mechanical means remove porcelain inhomogeneous, can't remove enamel fully, the blank easy deformation caused blank to be scrapped when thin-gage goods was subjected to clashing into, can't recycling.When shooting down enamel, goods are often polluted by greasy dirt and iron rust, so needing blank is carried out roasting and decontamination before the application of slip once more.
Summary of the invention
The objective of the invention is to overcome deficiency of the prior art, a kind of method of removing porcelain by hydrofluoric acid and co-producing white carbon black is provided.
Technical scheme of the present invention is summarized as follows:
The method of removing porcelain by hydrofluoric acid and co-producing white carbon black comprises the steps:
(1) the cast iron enamel defect ware immersed held in the reactor that massfraction is 75%～95% hydrofluoric acid aqueous solution, indirect heating, at 60 ℃～80 ℃, reaction 1h～3h has silicon tetrafluoride gas to generate, with liquid filtering in the described reactor, filtrate is re-entered in the reactor, all the other material massfractions are 10%～15% aqueous sodium hydroxide washes, reclaim cast iron, and waste residue is done further processing again;
(2) be that 10%～25% ammoniacal liquor absorbs silicon tetrafluoride gas and the evaporable hydrogen fluoride gas that mol ratio is 1:2 simultaneously with massfraction, the add-on of ammoniacal liquor is 1.1～1.5 times of theoretical amount, with massfraction is that 20%～40% ammonium fluoride aqueous solution absorbs still unabsorbed silicon tetrafluoride gas, heated solution obtains ammonium fluosilicate solution to boiling;
(3) pH with ammoniacal liquor adjusting ammonium fluosilicate solution is 7～8 under 70～80 ℃, reaction 0.75h～1h, there is precipitation to generate, filtering separation, filter cake is 5.0 with sulfuric acid acidation to pH value, at 80 ℃～100 ℃ following ageing 0.5～1h, filters, washes, drains, dry 1h～1.5h under 100 ℃～120 ℃ obtains white carbon black.
Described step (1) is preferably: the cast iron enamel defect ware is immersed held in the reactor that massfraction is 85% hydrofluoric acid aqueous solution, indirect heating, at 70 ℃, reaction 2h has silicon tetrafluoride gas to generate, with liquid filtering in the described reactor, filtrate is re-entered in the reactor, all the other material massfractions are 12% aqueous sodium hydroxide washes, reclaim cast iron, and waste residue is done further processing again.
Described step (2) is preferably: with massfraction is that 25% ammoniacal liquor absorbs silicon tetrafluoride gas and the evaporable hydrogen fluoride gas that mol ratio is 1:2 simultaneously, the add-on of ammoniacal liquor is 1.2 times of theoretical amount, with massfraction is that 30% ammonium fluoride aqueous solution absorbs still unabsorbed silicon tetrafluoride gas, heated solution obtains ammonium fluosilicate solution to boiling.
Handle cast iron enamel with method of the present invention, the rate of recovery can reach more than 90%.The rate of recovery less than 40% of more mechanical sand-blast improves nearly one times, has solved the problem that thin-walled enamel spare can't recycle with mechanical sand-blast simultaneously.Handle and also will carry out the oil removing removing rust after the sandblasting, and method of the present invention only needs the foundry goods that will obtain after filtration, simple again sandblasting can utilize again after the alkali cleaning, drying foundry goods.Present method has the reaction times weak point, and acid-utilising is reasonable, utilizes after the acid volatilization to make acid lose characteristics such as few again.
The raw material availability height, production cost is low.The raw material of present technique is silicon-dioxide and the hydrofluoric acid in the enamel.Wherein silicon (Si) is processed into white carbon black, and fluorine is in ammonium fluoride solution.Part ammonium fluoride solution reusable edible, all the other Neutral ammonium fluorides can be used as the intermediates that byproduct also can be used as other fluoride salts.Present technique all is processed into useful product with all elements in the raw material, its added value is highly improved, so production cost is low.The process non-pollution discharge.Hydrofluoric acid waste liquid after the use is capable of circulation to be used further in the cast iron enamel desilication reaction.Raw material and product reach comprehensive utilization, and economic benefit greatly improves.
Gained white carbon black quality product reaches the technical requirement of GB10517-1989.
Description of drawings
Fig. 1 is a process flow diagram of the present invention.
Embodiment
The present invention is further illustrated below in conjunction with specific embodiment.
Embodiment 1
(1) be example with graphitic cast iron enamel, graphitic cast iron enamel enamel prescription (w%)
In enamel is formed, SiO
2Be base stock, can form the enamelled skeleton.SiO
2At least in the composition of enamel raw material, occupy certain content and just can keep the enamelled structure.SiO in most of enamel material
2Content all surpasses more than the 50wt.%.The cast iron enamel defect ware immersed held in the reactor that massfraction is 85% hydrofluoric acid aqueous solution, use the water vapor indirect heating, at 70 ℃, reaction 2h has the silicon tetrafluoride gas generation, and the reaction that relates in the process has:
Na
2O+2HF＝2NaF+H
2O
K
2O+2HF＝2KF+H
2O
SiO
2+4HF＝SiF
4↑+H
2O
SiF
4+2HF＝H
2SiO
6
CaO+2HF＝CaF
2↓+H
2O
Al
2O
3+6HF＝2AIF
3+3H
2O
TiO
2+6HF＝H
2TiF
6+2H
2O
B
2O
3+6HF＝2BF
3+3H
2O
HF can generate silicofluoric acid with silicon-dioxide that exists or silicate effect in reaction.
6HF+SiO
2＝H
2SiF
6+2H
2O
In acidic solution, the silicofluoric acid vapor partial pressure increases with the raising of acid concentration and temperature, part is silicon tetrafluoride gas overflows.
H
2SiF
6＝SiF
4↑+2HF↑
As SiO
2When existing, above-mentioned reaction will aggravate.
2H
2SiF
6+SiO
2＝3SiF
4↑+2H
2O
With liquid filtering in the described reactor, filtrate is re-entered in the reactor, and all the other material massfractions are 12% aqueous sodium hydroxide washes, takes out cast iron and carries out utilizing after the simple sandblasting again, and waste residue is done further processing again; Having only silicon tetrafluoride in the reaction product is to exist with gaseous phase, other products or be dissolved in solution or form precipitation, and this just makes co-producing white carbon black have theoretic feasibility.Because temperature of reaction is higher, silicon tetrafluoride and partially fluorinated hydrogen will be overflowed with gaseous state;
(2) be that 10%～25% ammoniacal liquor absorbs silicon tetrafluoride gas and the evaporable hydrogen fluoride gas that mol ratio is 1:2 simultaneously with massfraction, the add-on of ammoniacal liquor is 1.1～1.5 times of theoretical amount,
2HF+SiF
4+2NH
3＝(NH
4)
2SiF
6
Silicon tetrafluoride content is more in the gas, is that 30% ammonium fluoride aqueous solution absorbs still unabsorbed silicon tetrafluoride gas with massfraction, makes unnecessary silicon tetrafluoride be converted into ammonium silicofluoride, and heated solution obtains ammonium fluosilicate solution to boiling;
SiF
4+2NH
4F＝(NH
4)
2SiF
6
(3) pH with ammoniacal liquor adjusting ammonium fluosilicate solution is 7 under 75 ℃, and reaction 1h has precipitation to generate,
(NH
4)
2SiF
6+4NH
3+2H
2O＝6NH
4F+SiO
2↓+4H
2O
Filtering separation, filter cake is 5.0 with sulfuric acid acidation to pH value, at 90 ℃ of following ageing 1h, filters, washes, drains, dry 1h under 110 ℃ obtains white carbon black.Can obtain simultaneously the Neutral ammonium fluoride filtrate of high density.Ammonium fluoride solution can be recycled; Also ammonium fluoride solution can be concentrated, crystallization, drying produce Neutral ammonium fluoride; Can also be starting point with the ammonium fluoride solution of high density produces other fluorine series product according to the needs in market, as Potassium monofluoride, Sodium Fluoride, sodium aluminum fluoride etc.
Embodiment 2
The method of removing porcelain by hydrofluoric acid and co-producing white carbon black comprises the steps:
(1) the cast iron enamel defect ware immersed held in the reactor that massfraction is 75% hydrofluoric acid aqueous solution, indirect heating, at 80 ℃, reaction 1h has silicon tetrafluoride gas to generate, with liquid filtering in the described reactor, filtrate is re-entered in the reactor, all the other material massfractions are 15% aqueous sodium hydroxide washes, reclaim cast iron, and waste residue is done further processing again;
(2) be that 25% ammoniacal liquor absorbs silicon tetrafluoride gas and the evaporable hydrogen fluoride gas that mol ratio is 1:2 simultaneously with massfraction, the add-on of ammoniacal liquor is 1.2 times of theoretical amount, with massfraction is that 30% ammonium fluoride aqueous solution absorbs still unabsorbed silicon tetrafluoride gas, heated solution obtains ammonium fluosilicate solution to boiling;
(3) pH with ammoniacal liquor adjusting ammonium fluosilicate solution is 8 under 70 ℃, and reaction 0.75h has precipitation to generate, filtering separation, and filter cake is 5.0 with sulfuric acid acidation to pH value, at 80 ℃ of following ageing 1h, filters, washes, drains, dry 1.5h under 100 ℃ obtains white carbon black.
Embodiment 3
The method of removing porcelain by hydrofluoric acid and co-producing white carbon black is characterized in that comprising the steps:
(1) the cast iron enamel defect ware immersed held in the reactor that massfraction is 95% hydrofluoric acid aqueous solution, indirect heating, at 60 ℃, reaction 3h has silicon tetrafluoride gas to generate, with liquid filtering in the described reactor, filtrate is re-entered in the reactor, all the other material massfractions are 10% aqueous sodium hydroxide washes, reclaim cast iron, and waste residue is done further processing again;
(2) be that 20% ammoniacal liquor absorbs silicon tetrafluoride gas and the evaporable hydrogen fluoride gas that mol ratio is 1:2 simultaneously with massfraction, the add-on of ammoniacal liquor is 1.5 times of theoretical amount, with massfraction is that 20% ammonium fluoride aqueous solution absorbs still unabsorbed silicon tetrafluoride gas, heated solution obtains ammonium fluosilicate solution to boiling;
(3) pH with ammoniacal liquor adjusting ammonium fluosilicate solution is 7 under 80 ℃, and reaction 1h has precipitation to generate, filtering separation, and filter cake is 5.0 with sulfuric acid acidation to pH value, at 100 ℃ of following ageing 0.5h, filters, washes, drains, dry 1h under 120 ℃ obtains white carbon black.
Embodiment 4
The method of removing porcelain by hydrofluoric acid and co-producing white carbon black is characterized in that comprising the steps:
(1) the cast iron enamel defect ware immersed held in the reactor that massfraction is 85% hydrofluoric acid aqueous solution, indirect heating, at 70 ℃, reaction 2h has silicon tetrafluoride gas to generate, with liquid filtering in the described reactor, filtrate is re-entered in the reactor, all the other material massfractions are 12% aqueous sodium hydroxide washes, reclaim cast iron, and waste residue is done further processing again;
(2) be that 10% ammoniacal liquor absorbs silicon tetrafluoride gas and the evaporable hydrogen fluoride gas that mol ratio is 1:2 simultaneously with massfraction, the add-on of ammoniacal liquor is 1.1 times of theoretical amount, with massfraction is that 40% ammonium fluoride aqueous solution absorbs still unabsorbed silicon tetrafluoride gas, heated solution obtains ammonium fluosilicate solution to boiling;
(3) pH with ammoniacal liquor adjusting ammonium fluosilicate solution is 8 under 75 ℃, and reaction 0.85h has precipitation to generate, filtering separation, filter cake is 5.0 with sulfuric acid acidation to pH value, at 90 ℃ of following ageing 0.8h, filter, wash, drain, dry 1.2h under 110 ℃ obtains white carbon black.
Claims (3)
1. the method for removing porcelain by hydrofluoric acid and co-producing white carbon black is characterized in that comprising the steps:
(1) the cast iron enamel defect ware immersed held in the reactor that massfraction is 75%～95% hydrofluoric acid aqueous solution, indirect heating, at 60 ℃～80 ℃, reaction 1h～3h has silicon tetrafluoride gas to generate, with liquid filtering in the described reactor, filtrate is re-entered in the reactor, all the other material massfractions are 10%～15% aqueous sodium hydroxide washes, reclaim cast iron, and waste residue is done further processing again;
(2) be that 10%～25% ammoniacal liquor absorbs silicon tetrafluoride gas and the evaporable hydrogen fluoride gas that mol ratio is 1:2 simultaneously with massfraction, the add-on of ammoniacal liquor is 1.1～1.5 times of theoretical amount, with massfraction is that 20%～40% ammonium fluoride aqueous solution absorbs still unabsorbed silicon tetrafluoride gas, heated solution obtains ammonium fluosilicate solution to boiling;
(3) pH with ammoniacal liquor adjusting ammonium fluosilicate solution is 7～8 under 70～80 ℃, reaction 0.75h～1h, there is precipitation to generate, filtering separation, filter cake is 5.0 with sulfuric acid acidation to pH value, at 80 ℃～100 ℃ following ageing 0.5～1h, filters, washes, drains, dry 1h～1.5h under 100 ℃～120 ℃ obtains white carbon black.
2. the method for removing porcelain by hydrofluoric acid and co-producing white carbon black according to claim 1, it is characterized in that described step (1) is: the cast iron enamel defect ware is immersed held in the reactor that massfraction is 85% hydrofluoric acid aqueous solution, indirect heating, at 70 ℃, reaction 2h, there is silicon tetrafluoride gas to generate, with liquid filtering in the described reactor, filtrate is re-entered in the reactor, and all the other material massfractions are 12% aqueous sodium hydroxide washes, reclaim cast iron, waste residue is done further processing again.
3. the method for removing porcelain by hydrofluoric acid and co-producing white carbon black according to claim 1, it is characterized in that described step (2) is: with massfraction is that 25% ammoniacal liquor absorbs silicon tetrafluoride gas and the evaporable hydrogen fluoride gas that mol ratio is 1:2 simultaneously, the add-on of ammoniacal liquor is 1.2 times of theoretical amount, with massfraction is that 30% ammonium fluoride aqueous solution absorbs still unabsorbed silicon tetrafluoride gas, heated solution obtains ammonium fluosilicate solution to boiling.
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| CN2009100686208A CN101531369B (en) | 2009-04-24 | 2009-04-24 | Method for removing porcelain by hydrofluoric acid and co-producing white carbon black |
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|---|---|---|---|
| CN2009100686208A CN101531369B (en) | 2009-04-24 | 2009-04-24 | Method for removing porcelain by hydrofluoric acid and co-producing white carbon black |
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| CN101531369A true CN101531369A (en) | 2009-09-16 |
| CN101531369B CN101531369B (en) | 2010-10-27 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103058202A (en) * | 2013-01-11 | 2013-04-24 | 瓮福（集团）有限责任公司 | Method for recycling silicon-producing white carbon black in wet-process phosphoric acid tail gas |
| CN103663499A (en) * | 2013-11-13 | 2014-03-26 | 安徽六国化工股份有限公司 | Method for preparing potassium fluoride and coproducing ultrafine white carbon black from ammonium fluorosilicate byproduct in phosphate fertilizer production |
| CN103950941A (en) * | 2014-05-12 | 2014-07-30 | 连云港市东海县宏伟石英制品有限公司 | Method for chemically preparing ultra-high-purity quartz powder |
| CN106365189A (en) * | 2016-08-29 | 2017-02-01 | 昆明理工大学 | Comprehensive utilization method of silicon residue soil |
-
2009
- 2009-04-24 CN CN2009100686208A patent/CN101531369B/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103058202A (en) * | 2013-01-11 | 2013-04-24 | 瓮福（集团）有限责任公司 | Method for recycling silicon-producing white carbon black in wet-process phosphoric acid tail gas |
| CN103663499A (en) * | 2013-11-13 | 2014-03-26 | 安徽六国化工股份有限公司 | Method for preparing potassium fluoride and coproducing ultrafine white carbon black from ammonium fluorosilicate byproduct in phosphate fertilizer production |
| CN103663499B (en) * | 2013-11-13 | 2015-08-26 | 安徽六国化工股份有限公司 | The method of Potassium monofluoride co-production of ultrafine white carbon black is prepared with phosphate fertilizer by-product ammonium silicofluoride |
| CN103950941A (en) * | 2014-05-12 | 2014-07-30 | 连云港市东海县宏伟石英制品有限公司 | Method for chemically preparing ultra-high-purity quartz powder |
| CN106365189A (en) * | 2016-08-29 | 2017-02-01 | 昆明理工大学 | Comprehensive utilization method of silicon residue soil |
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| CN101531369B (en) | 2010-10-27 |
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