CN1173893C - A kind of polymerized basic aluminum silicon flocculant and preparation method thereof - Google Patents

Abstract

The invention relates to a polymeric basic aluminum-silicon flocculant and a preparation method thereof. The flocculant is made by pre-polymerizing silicic acid under alkaline conditions to reach the required molecular weight (that is, the range is 30000-120000), and then adding aluminum sulfate and sodium hydroxide to polymerize under rapid stirring to form a polymeric basic aluminum-silicon flocculant . This method obtains products with different molecular weights by changing the degree of polymerization of silicic acid and the ratio of silicon to aluminum, which can meet different water treatment requirements. The product has strong adsorption and aggregation, and can be widely used in water supply treatment and industrial wastewater treatment. The source of production raw materials is wide, the price is cheap, the operating cost is relatively low, and it is easy to be accepted by the market.

Description

A kind of polymerization alkali formula aluminium silicon flocculation agent and preparation method thereof

The present invention relates to a kind of water treatment flocculant, specifically be meant a kind ofly to can be used for feeding water and the polymerization alkali formula aluminium silicon flocculation agent of wastewater treatment and preparation method thereof.

In feedwater and wastewater treatment, can use Tai-Ace S 150 usually, because the Tai-Ace S 150 price is relatively cheap, and be easy to obtain, treatment effect is also good.But Tai-Ace S 150 treatment effect when low temperature is bad, and formed flco is light, is difficult to sedimentation, the aluminium content height of remnants in the water body when giving water treatment.

At Tai-Ace S 150 deficiency in use, people have carried out a large amount of research to this, find to make silicon and aluminium by certain form combination, can form a kind of new flocculation agent, and this flocculation agent has some new characteristics.For example: Chinese patent application CN87101246A has introduced a kind of water treatment method, and it adopts high-polymerization degree silicic acid and a spot of aluminium salt to use together.This flocculation agent is owing to adopted the silicic acid of high-polymerization degree, therefore it has higher molecular weight, very strong ability of aggregation is arranged when treating water, treatment effect is good, but the poly-silicic acid and the inorganic coagulant of this kind product will separately be produced, store, be preferably in the use situ production, the preservation period of product is not long, uses inconvenient.

Chinese patent ZL89108931.4 and 93116227.0 has introduced a kind of polymeric basic aluminium silicate-sulphate.It is to adopt alkalimetal silicate, alkali metal aluminate and Tai-Ace S 150 hybrid reaction to produce polymeric basic aluminium silicate-sulphate.This flocculation agent has flocculating effect preferably when low temperature, and can reduce the content of free aluminum in the water when the processing of supplying water is used.But, since this flocculation agent in silica alumina ratio less than 0.1[Si/Al≤0.1 (mol ratio)], use range is subject to certain restrictions.

Chinese patent ZL90108702.5 has introduced a kind of polymeric silicicacid/aluminium salt mixture flocculation agent.This flocculation agent is a main raw material with the water slag, under normal temperature and pressure, with hydrochloric acid or/and the sulfuric acid dissolution polymerization, the elimination insolubles, the polymerization slaking and adjust pH value after promptly get product.This method raw material is easy to get, and cost is low, and production method is simple.But, be difficult to each components in proportions of product is regulated because material composition can not be controlled.

The objective of the invention is to overcome the deficiencies in the prior art part, study a kind of can be by changing silicic acid the polymerization degree and the ratio of sial obtain polymerization alkali formula aluminium silicon flocculation agent of different molecular weight and preparation method thereof.

A kind of polymerization alkali formula aluminium flocculating agent is characterized in that it is to be formed by Tai-Ace S 150, water glass and sodium hydroxide sodium polymerization, when product is aqueous solution form, has following chemical constitution and weight percent content thereof:

Al ₂O ₃ 4.00-6.00％

SiO ₂ 0.94-3.53％

SO ₄ ^2- 11.07-16.94％

Na ⁺ 1.91-11.4％

H ₂O 62.13-82.08％

The pH value of the aqueous solution is 2.5-3.0, and basicity is 45%-70%.

A kind of preparation method of polymerization alkali formula aluminium silicon flocculation agent, it comprises following processing step and condition thereof:

Step 1: get the raw materials ready:

Tai-Ace S 150: 13.41～20.12%

Water glass: 1.91～7.18%

Sodium hydroxide: 2.07～15.11%

Water: 57.59～82.61%

Step 2: the prepolymerization of poly-silicic acid:

Water glass is regulated pH value to 9.0～10.5 with acid, 1～16 hour pre-polymerization time, molecular weight ranges is 3000～120000 poly-silicic acid;

Step 3: polyreaction:

(1) earlier aluminum sulfate aqueous solution is put into reactor, under whipped state, use fast separating device, within 15～20 minutes, slowly add the poly-silicic acid that step 2 gets, and use volume pump control feed rate, adopt water coolant to keep temperature of reaction kettle in 18～22 ℃ of scopes simultaneously;

(2) then under above-mentioned similarity condition,, in 20～30 minutes, slowly add aqueous sodium hydroxide solution by fast separating device through volume pump control feed rate;

(3) hydro-oxidation sodium was closed fast separating device after 20～40 minutes, closed water coolant, opened steam valve, made the material in the reactor be warming up to 60～70 ℃ 0.8～within an hour, isothermal reaction 3～5 hours; Perhaps at normal temperatures, stirring reaction 20～24 hours, naturally cooling promptly gets product then, and its molecular weight ranges is 10 ³～10 ⁵, when check contains product in aqueous solution form, contain following chemical constitution and weight percent content thereof:

Al ₂O ₃ 4.00-6.00％

SiO ₂ 0.94-3.53％

SO ₄ ^2- 11.07-16.94％

Na ⁺ 1.91-11.4％

H ₂O 62.13-82.08％

The pH value of the aqueous solution is 2.5-3.0, and basicity is 45%-70%.

The isolated plant of production polymerization alkali of the present invention formula aluminium silicon flocculation agent comprises that a band can feed the reactor 1 of the chuck of water coolant or steam, and the outlet 10 of a discharging product is arranged at reactor 1 bottom, and conventional whisk 2 and fast separating device 3 are housed in the reactor 1; Poly-silicic acid storage tank 7 and sodium hydroxide storage tank 8 communicate with reactor 1 by the pipeline 4,5 that has volume pump 6,9 respectively;

The present invention compared with prior art has following outstanding advantage:

1, the polymerization alkali formula aluminium silicon flocculation agent of the present invention's production, molecular weight is bigger, and the impurity in the water is had very high adsorpting aggregation effect, can form big flocs unit fast in water, the scope of application is wide, and treatment effect is good, ratio of performance to price height, concrete quantized data sees application examples 1 for details: drinking original water is handled; Application examples 2: paper-reproducing wastewater is handled; Application examples 3: treatment of dyeing wastewater.

2, production method of the present invention, the polymerization degree that can be by changing silicic acid and the ratio of sial obtain the product of different molecular weight, to satisfy the requirement of different water treatments; Owing to rich raw material sources, low price, therefore, use the working cost of this product relatively low again.

3, technical process of the present invention is simple, and device structure is reasonable, and is easy to operate, and the poly-silicic acid and the inorganic coagulant that have overcome the product of CN87101246 need separately be produced, store, and preservation period is short, uses inconvenient shortcoming; Also having overcome the ZL90108702.5 material composition can not control, the difficult shortcoming of regulating of each component proportions of product.

Fig. 1 is a kind of structural representation of polymerization alkali formula aluminium silicon flocculating agent preparing apparatus.

By following embodiment and accompanying drawing thereof, the invention will be further described for Application Example:

Embodiment 1

As shown in Figure 1,1 is reactor, and 2 is agitator, and 3 is fast separating device, and 4,5 is pipeline, and 6,9 is volume pump, and 7,8 is storage tank, and 10 is products export.Storage tank the 7, the 8th communicates with reactor 1 by the pipeline 4,5 that has volume pump 6,9, and pipeline 4,5 exit end are 0.09m with entrance end distance of putting quick in bulk.

In reactor 1, add and contain Al ₂O ₃Be 31.57 kilograms of 9.5% aluminum sulfate aqueous solutions, start agitator 2.

Be that 12.55 kilograms of 2.63% poly-silicate aqueous solutions add in the storage tank 7 containing Si on request, open fast separating device 3, open the cooling water valve of reactor 1 simultaneously, keep in the reactor temperature ℃ between.With volume pump 6 the poly-silicic acid in the groove 7 is pumped in the reactor 1 by pipeline 5, the feed rate of control volume pump 6 makes poly-silicic acid add at 15～20 minutes.

Containing NaOH is that 50% aqueous sodium hydroxide solution adds in the storage tank 8 for 5.88 kilograms, with volume pump 9 sodium hydroxide solution in the storage tank 8 is pumped in the reactor 1 by pipeline 4 then, in 20～30 minutes, add, and short mix, carry out polyreaction.

Add sodium hydroxide after 30 minutes, close fast separating device 3, close water coolant, open steam valve, make the material in the reactor 1 in 0.8-1 hour time, be warming up to 60-70 ℃, isothermal reaction 4 hours, naturally cooling promptly gets product then.

Embodiment 2

Present embodiment equipment therefor, reactions steps, feeding sequence and feeding mode are with embodiment 1, and feed ratio changes into:

Contain Al ₂O ₃Be 8.11% aluminum sulfate aqueous solution: 24.66 kilograms

Contain Si and be 2.50% poly-silicate aqueous solution: 21.94 kilograms

Contain NaOH and be 30% aqueous sodium hydroxide solution: 3.40 kilograms

Feed intake finish after, without steam heating, material promptly gets product at the following stirring reaction 24 hours of normal temperature (about 30 ℃).

Embodiment 1,2 products obtained therefrom proterties are as follows:

	Embodiment 1	Embodiment 2	High-quality PAC
				Outward appearance	Colourless transparent liquid	Colourless transparent liquid	Light yellow liquid
PH	2.5-2.8	2.5-2.8	3.5-3.8
				Al 2O 3(％)	6.0	4.0	8％
Si/A1 (mol ratio)	0.2	0.5
				Particle diameter (nm)	300-410	290-380	200-260
Molecular weight (dalton %)	＜1000 15-30％ ＞105 20-35％	＜1000 20-30％ ＞105 15-30％	＜1000 30-50％ ＞105 5-15％

Application Example 1: drinking original water is handled

Former water is taken from section, Zhujiang River Guangzhou

1, water quality:

Turbidity (NTU) 35.7

Water temperature (℃) 23

PH 6.81

Ammonia nitrogen (mg/l) 4.03

UV ₂₅₄(cm ^-1) 0.092

2, treatment process:

Get special-purpose 1 liter of measuring cup, inject water sample, 300r/min adds the flocculation agent 0.05ml that embodiment 1 makes at ZR six agitators control rotating speed, speed governing is 150r/min after 1 minute, continue to stir 5 minutes, last speed governing is that 60r/min stirred 10 minutes, and standing sedimentation 20 minutes is apart from liquid level 2-3cm place sampling and measuring turbidity, filter membrane coefficient (after sand filtration), residual aluminum content and UV ₂₅₄Data such as value.

3, coagulation decontamination effect improving

On multiple batches of experimental basis, make quantitative simultaneous test, make assay

PASS1-embodiment 1 sample

PASS2-embodiment 2 samples

SA-technical grade Tai-Ace S 150

PAC-high-quality polymeric aluminium chlorohydroxide

Dosage: 3.0mg/l is (with Al ₂O ₃Meter)

Can find out from experiment, be that 3.0mg/l is (with Al at dosage ₂O ₃Meter) time, the effect of PASS is much better than Tai-Ace S 150, also is better than polymeric aluminium chlorohydroxide.

PASS is to UV ₂₅₄The organic matter removal effect of representative is better than Tai-Ace S 150 and polymeric aluminium chlorohydroxide, and this is owing to contain two kinds of different electrical ions of aluminium and silicon simultaneously among the PASS.

PASS makes in after treatment the water than Tai-Ace S 150 and polymeric aluminium chlorohydroxide lower remaining aluminium amount, makes the remaining aluminium amount tentative standard (0.2mg/l) that more easily reaches the new promulgation of country to the water outlet after the water treatment.

Filter membrane coefficient (Mf=V/pt) expression " under certain pressure and time; water flows through the mean flow rate on certain filter membrane surface " of water, it has represented the filtrability of water, also reflected the situation of fine particle in the water, the filter membrane coefficient is more little, and is promptly long more by the time of 0.45 μ m filter membrane, show that the ultrafine particle thing (＜5 μ m) in the water is many more, can find out that from test the filter membrane coefficient ratio PAC of PASS and SA's is big, shows that PASS is better to the absorption property of subparticle.

Application examples 2: paper-reproducing wastewater is handled

Former water is taken from wastewater from regenerating paper production

1, water quality:

COD：800-1500mg/l

BOD：300-580mg/l

SS： 500-1500mg/l

2, treatment process:

Treatment process adds the flocculation agent 400-600ppm that example 2 makes with application examples 1.

3, decontamination effect improving:

Effluent quality:

COD：105-150mg/l

BOD：22-56mg/l

SS： 30-45mg/l

Application examples 3: treatment of dyeing wastewater

Former water is taken from certain cotton products printing and dyeing mill, and used dyestuff has activity, dispersion etc.

1, water quality:

Color: red, yellow, black

Colourity: 300-500 (doubly)

COD： 450-600mg/l

2, treatment process:

Treatment process adds the flocculation agent 500-800ppm that embodiment 1 makes with application examples 1.

3, decontamination effect improving:

Effluent quality:

Colourity: 50-80 (doubly)

COD： 150-220mg/l

Claims (2)

1. A polymeric basic aluminum-silicon flocculant, which is characterized in that it is polymerized from aluminum sulfate, sodium silicate and sodium hydroxide. When the product is in the form of an aqueous solution, the composition and weight percentage are as follows: Al ₂ O ₃ 4.00-6.00% SiO ₂ 0.94-3.53% _SO4 ^2- 11.07-16.94% Na ⁺ 1.91-11.4% _H2O 62.13-82.08% The pH value of the aqueous solution is 2.5-3.0, and the salinity is 45%-70%. 2. A method for preparing a polymeric basic aluminum-silicon flocculant, characterized in that it comprises the following process steps and conditions thereof: Step 1: Prepare materials: Aluminum sulfate: 13.41～20.12% Sodium silicate: 1.91～7.18% Sodium hydroxide: 2.07～15.11% Water: 57.59～82.61% Step 2: Pre-polymerization of polysilicic acid: Sodium silicate is used to adjust the pH value to 9.0-10.5 with acid, and the prepolymerization time is 1-16 hours to obtain polysilicic acid with a molecular weight range of 3000-120000; Step 3: Polymerization: (1) Put the aluminum sulfate aqueous solution into the reaction kettle first, and in the stirring state, use the rapid dispersion device to slowly add the pre-polymerized silicic acid within 15 to 20 minutes, and use the metering pump to control the feeding speed, and use cooling water at the same time Keep the temperature of the reactor within the range of 18-22°C; (2) Then under the above-mentioned same conditions, the feeding speed is controlled by the metering pump, and the sodium hydroxide aqueous solution is slowly added in 20 to 30 minutes by the rapid dispersion device; (3) After adding sodium hydroxide for 20-40 minutes, turn off the rapid dispersion device, turn off the cooling water, and open the steam valve, so that the material in the reaction kettle is heated to 60-70°C within 0.8-1 hour, and the constant temperature reaction is 3-70°C. 5 hours, then naturally cooled to obtain the product, its molecular weight range is 103～105, and when the product is in the form of aqueous solution after inspection, it contains the following chemical composition and its weight percentage content: Al ₂ O ₃ 4.00-6.00% SiO ₂ 0.94-3.53% _SO4 ^2- 11.07-16.94% Na ⁺ 1.91-11.4% _H2O 62.13-82.08% The pH value of the aqueous solution is 2.5-3.0, and the salinity is 45%-70%.

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