阅读说明：本技术 利用废催化剂制备聚硅铝的方法 (Method for preparing polysilicon-aluminum by using waste catalyst ) 是由 王文泽 梁之举 王居亮 于 2019-11-06 设计创作，主要内容包括：本发明属于固体废物综合利用和絮凝剂生产技术领域,具体的涉及一种利用废催化剂制备聚硅铝的方法。将氢氧化钠溶液与FCC废催化剂进行升温加压反应,过滤制得铝硅酸盐溶液；向铝硅酸盐溶液中滴加硫酸或盐酸,调节pH为0.8～1.7,熟化1～2h,得到液体聚硅硫酸铝或聚硅氯化铝。本发明所述的利用废催化剂制备聚硅铝的方法,避免了酸浸法重金属离子一起浸出造成二次污染的风险,是一种工艺路线简单、生产成本低廉、Al<Sub>2</Sub>O<Sub>3</Sub>与SiO<Sub>2</Sub>溶出率高的聚硅铝的制备方法。(The invention belongs to the technical field of comprehensive utilization of solid wastes and production of flocculants, and particularly relates to a method for preparing polysilicon-aluminum by using a waste catalyst. Carrying out heating and pressurizing reaction on a sodium hydroxide solution and an FCC waste catalyst, and filtering to obtain an aluminosilicate solution; and (3) dripping sulfuric acid or hydrochloric acid into the aluminosilicate solution, adjusting the pH to 0.8-1.7, and curing for 1-2 hours to obtain liquid polyaluminum silicate sulfate or polyaluminum silicate chloride. The method for preparing the silicon-aluminum-polysilicate by using the waste catalyst avoids the risk of secondary pollution caused by leaching of heavy metal ions together by an acid leaching method, and has the advantages of simple process route, low production cost and Al 2 O 3 With SiO 2 A preparation method of polysilicon-aluminum with high dissolution rate.)

1. A method for preparing polysilicon-aluminum by using a waste catalyst is characterized by comprising the following steps: prepared by the following steps:

(1) carrying out heating and pressurizing reaction on a sodium hydroxide solution and an FCC waste catalyst, and filtering to obtain an aluminosilicate solution;

(2) and (3) dripping sulfuric acid or hydrochloric acid into the aluminosilicate solution, adjusting the pH to 0.8-1.7, and curing for 1-2 hours to obtain liquid polyaluminum silicate sulfate or polyaluminum silicate chloride.

2. The method for preparing silicoaluminophosphate using a spent catalyst according to claim 1, characterized in that: the mass concentration of the sodium hydroxide solution in the step (1) is 20-50%.

3. The method for preparing silicoaluminophosphate using a spent catalyst according to claim 1, characterized in that: the temperature rise and pressure rise reaction in the step (1): the rotating speed is controlled to be 600-1000 r/min, the reaction temperature is 120-150 ℃, the reaction pressure is 0.3-0.5 MPa, and the reaction time is 1.5-3 h.

4. The method for preparing silicoaluminophosphate using a spent catalyst according to claim 1, characterized in that: the mass-to-volume ratio of the FCC spent catalyst to the sodium hydroxide solution in the step (1) is 10: 13-41, and the unit is g/ml.

5. The method for preparing silicoaluminophosphate using a spent catalyst according to claim 1, characterized in that: the FCC spent catalyst in the step (1) comprises Al in percentage by mass₂O₃45～65％、SiO₂38-49%, and the balance being impurities.

6. The method for preparing silicoaluminophosphate using a spent catalyst according to claim 1, characterized in that: the mass concentration of the sulfuric acid or the hydrochloric acid in the step (2) is 20-30%.

7. The method for preparing silicoaluminophosphate using a spent catalyst according to claim 1, characterized in that: the dripping time in the step (2) is 0.5-1 h, and the reaction temperature is 50-80 ℃.

Technical Field

The invention belongs to the technical field of comprehensive utilization of solid wastes and production of flocculants, and particularly relates to a method for preparing polysilicon-aluminum by using a waste catalyst.

Background

Polyaluminum silicate sulfate (PASS) and polyaluminum silicate chloride (PASC), which are hereinafter collectively referred to as "polysilica-aluminum". The polysilicate-aluminum is a water-soluble inorganic high molecular polymer, and has the characteristics of strong bridging adsorption capacity, high cationic degree, high water solubility, no gel formation, good hydrolytic stability, wide water quality range, no influence of low water temperature and the like. The positive charges carried by the macromolecular chains of the poly-silicon-aluminum have high density, and the product has good water solubility and moderate molecular weight, thereby having double performances of flocculation and disinfection. It not only effectively reduces the suspended solids content of the water and thus reduces the turbidity of the water, but also allows the virus to settle and reduces the action of trihalomethane precursors in the water, thus reducing the total carbon content (TOC) in the water. The polysilica-aluminum can be used as a main flocculant and a coagulant aid, has obvious effect on the clarification of water, particularly on the treatment of low-turbidity water, and is beyond the reach of other types of polymeric flocculants. Compared with the traditional inorganic flocculating agent (such as aluminum sulfate, basic aluminum chloride and the like), the method has the characteristics of less sludge generation, high settling speed, good water quality, low cost and the like, and can also adopt a new process of direct filtration, which undoubtedly is a great reform for the traditional flocculating agent.

At present, the process route for producing the poly-silicon-aluminum at home and abroad is ① that sodium hydroxide and calcium aluminate powder are used as raw materials to synthesize an aluminum sulfate solution or an aluminum chloride solution through acidolysis reaction, ② sodium silicate is used as a main raw material and is heated and pre-polymerized under an alkaline condition, ③ the pre-polymerized sodium silicate solution is added into the synthesized aluminum salt solution according to a certain proportion, and the temperature is raised and the poly-silicon-aluminum is obtained₂O₃The content is about 64 percent, and the price is 1900 yuan/ton; al in calcium aluminate powder₂O₃The content is about 52-55%, the price is 1200 yuan/ton, but the production cost is high, the process route is complex, filter residue generated after calcium aluminate powder acidolysis is not easy to filter, and the filter residue is difficult to treat and causes solid pollutants. Therefore, from the viewpoints of reducing the production cost, reducing the discharge of three wastes and protecting the development of ecological environment, various cheap production raw materials are sought, and a method for preparing the silicon-aluminum-polysilicate by improving a simple process route is necessary.

The FCC spent catalyst is a solid waste product from a petroleum catalytic plant and often contains toxic components, mainly heavy metals, deposited on the catalyst to poison and deactivate the catalyst. For example, NiO, when the mass fraction is more than 0.1 percent, the solid waste of the catalytic device belongs to dangerous solid waste; and when the mass fraction of V, Sb, Ti and the like is more than 3 percent, the solid waste of the catalytic device also belongs to dangerous solid waste. If the solid waste of the catalytic device is piled in the open for a long time, a large amount of land resources are occupiedThe toxic and harmful components in the soil can enter water and soil along with the washing of rainwater, so that the water and soil, vegetation, organisms and the like are damaged, and the health of a human body is endangered through a food chain. Therefore, it is important to dispose the solid waste of the catalytic device in a harmless way. In addition, the solid waste of the catalytic device contains valuable metals with higher content, and the common catalyst is Al₂O₃With SiO₂Is a carrier, and the main component comprises Al in percentage by mass₂O₃About 45-65% of SiO₂About 38-49 percent, is a good raw material for preparing the poly-silicon aluminum sulfate and the poly-silicon aluminum chloride, and can be recycled as a secondary resource. The comprehensive utilization of the solid waste of the catalytic device can improve the resource utilization rate, avoid the environmental problems caused by the solid waste of the catalytic device and realize sustainable development. Therefore, efficient treatment and utilization of spent refinery catalysts has become a very important issue.

Patent CN1704350A describes a method for preparing polysilicate aluminum sulfate flocculant by using waste catalyst, the process route is to leach out metal component (Al) in catalyst by heating sulfuric acid and waste catalyst and acid dissolving₂O₃Fe, Ni, V, Ti, etc.) to prepare an aluminum salt solution; the remaining residue (SiO)₂) Reacting with sodium hydroxide solution to generate sodium silicate solution; polymerizing the aluminum salt solution and the sodium silicate solution according to a certain proportion to prepare the liquid polyaluminum silicate sulfate. The method has simple process route, provides a low-cost synthesis route for the preparation of the polyaluminium silicate sulfate, but harmful elements such as heavy metals Ni, V, Ti, Pb, Sb and the like in the waste catalyst enter the product, and if the method is applied to the water treatment industry, secondary pollution of water quality is easily caused.

Disclosure of Invention

The purpose of the invention is: overcomes the defects of the prior art and provides a method for preparing polysilicon-aluminum by using a waste catalyst. Avoids the risk of secondary pollution caused by leaching of heavy metal ions together by an acid leaching method, and has the advantages of simple process route, low production cost and Al₂O₃With SiO₂A preparation method of polysilicon-aluminum with high dissolution rate.

The method for preparing the silicon-aluminum-based polymer by using the waste catalyst comprises the following steps:

(1) carrying out heating and pressurizing reaction on a sodium hydroxide solution and an FCC waste catalyst, and filtering to obtain an aluminosilicate solution;

(2) and (3) dripping sulfuric acid or hydrochloric acid into the aluminosilicate solution, adjusting the pH to 0.8-1.7, and curing for 1-2 hours to obtain liquid polyaluminum silicate sulfate or polyaluminum silicate chloride.

Wherein:

the mass concentration of the sodium hydroxide solution in the step (1) is 20-50%.

The temperature rise and pressure rise reaction in the step (1): the rotating speed is controlled to be 600-1000 r/min, the reaction temperature is 120-150 ℃, the reaction pressure is 0.3-0.5 MPa, and the reaction time is 1.5-3 h.

The mass-to-volume ratio of the FCC spent catalyst to the sodium hydroxide solution in the step (1) is 10: 13-41, and the unit is g/ml.

The FCC spent catalyst in the step (1) comprises Al in percentage by mass₂O₃45～65％、SiO₂38-49% and the balance of Fe, Ni, V, Ti, Pb, Sb, Ca, K and other metal impurities.

The temperature-increasing and pressure-increasing reaction described in the step (1) is carried out in an autoclave.

Leaching aluminum-silicon components of the FCC spent catalyst by using liquid alkali in the step (1); the obtained aluminosilicate solution is a mixture solution of sodium aluminate and sodium silicate.

The mass concentration of the sulfuric acid or the hydrochloric acid in the step (2) is 20-30%.

The dripping time in the step (2) is 0.5-1 h, and the reaction temperature is 50-80 ℃.

As a preferred technical scheme, the method for preparing the poly-silicon-aluminum by using the waste catalyst is prepared by the following steps:

(1) heating and pressurizing 130-410 ml of 20-50% sodium hydroxide solution and 100g of FCC spent catalyst in a high-pressure kettle for reaction, controlling the rotating speed to be 600-1000 r/min, the reaction temperature to be 120-150 ℃, the reaction pressure to be 0.3-0.5 MPa and the reaction time to be 1.5-3 h, and taking the solution as liquidLeaching aluminum-silicon components of the FCC spent catalyst by using alkali, and filtering to obtain an aluminosilicate solution (sodium aluminate and sodium silicate); the FCC spent catalyst comprises Al as a component in percentage by mass₂O₃45～65％、SiO₂38-49% and the balance of Fe, Ni, V, Ti, Pb, Sb, Ca, K and other metal impurities.

(2) Dropwise adding 20-30% sulfuric acid or hydrochloric acid into an aluminosilicate solution, adjusting the pH to 0.8-1.7, wherein the dropwise adding time is 0.5-1 h, and the reaction temperature is 50-80 ℃; and curing the material after pH adjustment for 1-2 hours under slow stirring to obtain liquid polyaluminum silicate sulfate or polyaluminum silicate chloride.

The method for preparing the silicon-aluminum-based polymer by using the waste catalyst has the following reaction mechanism:

the main reaction equation of the poly-aluminum silicate sulfate is as follows:

Al₂O₃+2NaOH→2NaAlO₂+H₂O

SiO₂+2NaOH→Na₂SiO₃+H₂O

Na₂SiO₃+H₂O+H₂SO₄→H₄SiO₄+Na₂SO₄

2NaAlO₂+4H₂SO₄→Al₂(SO₄)₃+Na₂SO₄+4H₂O

Al₂(SO₄)₃+12H₂O→Al₂(OH)n(SO₄)(3-1/2n)+(12-n)H₂O+1/2n H₂SO₄

mAl₂(OH)n(SO₄)(3-1/2n)+mH₂O→[Al₂(OH)n(SO₄)(3-1/2n)xH₂O]m

the main reaction equation of the poly-silicon aluminum chloride is as follows:

Al₂O₃+2NaOH→2NaAlO₂+H₂O

SiO₂+2NaOH→Na₂SiO₃+H₂O

Na₂SiO₃+H₂O+2HCl→H₄SiO₄+2NaCl

NaAlO₂+4HCl→AlCl₃+NaCl+2H₂O

2AlCl₃+12H₂O→Al₂(OH)n Cl(6-n)+(12-n)H₂O+nHCl

mAl₂(OH)nCl(6-n)+mH₂O→[Al₂(OH)nCl(6-n).xH₂O]m

the mass concentration of the sodium hydroxide solution in the step (1) is 20-50%. Selecting sodium hydroxide solution with the concentration, wherein Al is mainly generated when the concentration of the sodium hydroxide solution is lower than 20 percent₂O₃The leaching rate of the SiO is less than 80 percent₂The leaching rate is less than 55 percent, and the reaction time is longer; the sodium hydroxide concentration is higher than 50%, and the sodium hydroxide is viscous, has poor dispersibility and is not easy to filter.

The FCC catalyst in the step (1) comprises Al in percentage by mass₂O₃45-65% of SiO₂38-49 percent of the total metal, and the balance of metal impurities such as iron, nickel, vanadium, antimony, titanium, calcium, potassium, magnesium, lead and the like.

And (2) heating and pressurizing the sodium hydroxide solution and the FCC spent catalyst in the step (1) to react in a high-pressure kettle, controlling the rotating speed to be 600-1000 r/min, controlling the reaction temperature to be 120-150 ℃, controlling the reaction pressure to be 0.3-0.5 MPa, and controlling the reaction time to be 1.5-3 h. The reaction temperature and reaction pressure are selected, and mainly residual petroleum components in the catalyst after volatilization of short olefins are attached to the surface of the catalyst to form a protective layer, so that the treatment is very difficult. If the reaction temperature is lower than 120 ℃ and the reaction pressure is lower than 0.3MPa, alkaline leaching Al₂O₃And SiO₂The time is long, and the leaching rate is lower than a normal value; if the reaction temperature is higher than 150 ℃ and the reaction pressure is higher than 0.5MPa, the alkaline leaching reaction is very quick, but the requirements on the performance of equipment are high, the equipment investment is large, andthe energy consumption is higher.

The filter residue obtained by filtering the reaction solution in the step (1) mainly contains metal impurities such as Fe, Ni, V, Ti, Pb, Sb, Ca, K and the like and unreacted Al₂O₃And SiO₂(ii) a Can be transported to cement enterprises to be used as raw materials of building materials.

The sulfuric acid and the hydrochloric acid in the step (2) are solutions with mass concentration of 20-30%. The solution with the concentration is selected, the purchase and the preparation are convenient, and after the solution is added into a reaction system, the dispersion is rapid, and the pH adjustment is sensitive; secondly, the concentration of the sulfuric acid or the hydrochloric acid is too low, the adding amount is relatively increased, and the effective component Al in the prepared poly-silicon-aluminum₂O₃And SiO₂The content is lower than the commercial industry standard of polysilicon and aluminum.

Adjusting the pH value to be 0.8-1.7 in the step (2), wherein the dripping time is 0.5-1 h, and the reaction temperature is 50-80 ℃; and curing the material after pH adjustment for 1-2 hours under slow stirring to obtain liquid polyaluminum silicate sulfate or polyaluminum silicate chloride. The pH value range is selected to ensure that the basicity of the polyaluminum silicate meets the industrial standard; the dropping time is selected to be 0.5-1 h, so that the reaction temperature is conveniently controlled; if the dripping is too fast, the neutralization reaction of acid and alkali is rapid and exothermic, and the polymerization temperature is not easy to control; the dripping is too slow, and the production period is longer; the polymerization temperature is selected to be 50-80 ℃, because when the temperature is higher than 80 ℃, the sodium aluminate undergoes hydrolysis reaction to generate water-insoluble aluminum hydroxide precipitate, which affects the product quality; when the temperature is lower than 50 ℃, the sodium silicate generated in the step (1) is self-polymerized into gel viscous liquid, the dispersibility is poor, and the curing time is long.

The quality index of the liquid poly-silicon-aluminum product obtained by the invention is Al₂O₃4.5 to 5.5 percent of SiO₂2-3%, pH 3-4, basicity 32-66% and insoluble substance not more than 0.2%, and meets the commercial silicon-aluminum industry standard.

Compared with the prior art, the invention has the following beneficial effects:

(1) the method for preparing the polysilicate-aluminum by using the waste catalyst takes the FCC waste catalyst as a main raw material, so that the production cost of the polysilicate-aluminum and the polysilicate-aluminum chloride is greatly reduced; and the present inventionIn the method, aluminum and silicon in the FCC catalyst are leached by a sodium hydroxide solution, so that heavy metal ions such as iron, cadmium, nickel, zinc, vanadium and the like enter a flocculating agent in the traditional acid leaching method and are applied to secondary pollution of water quality caused by the water treatment industry; simultaneously, the polysilicic acid coagulant aid is prepared by leaching silicon in the waste catalyst, the process link of leaching silicon by alkali after the traditional acid leaching method is reduced, the reaction rate is accelerated by the temperature rise and pressure alkali leaching reaction, and the Al is improved₂O₃And SiO₂The leaching rate of (A). The filter residue after the reaction is very little, and can be directly transported to a cement enterprise to be used as a processing raw material of a building material, so that ecological pollution can not be caused.

(2) The method for preparing the silicon-aluminum-polysilicate by using the waste catalyst avoids the risk of secondary pollution caused by leaching of heavy metal ions together by an acid leaching method, and has the advantages of simple process route, low production cost and Al₂O₃With SiO₂A preparation method of polysilicon-aluminum with high dissolution rate.

Detailed Description

The present invention is further described below with reference to examples.

The present invention is further illustrated by the following specific examples, of which example 1 is the most preferred. The following examples and comparative examples were carried out using the same batch of FCC spent catalyst, and the mass percentage composition of the spent catalyst was examined as Al₂O₃52.5% of SiO₂43% of the total amount of the metal oxide particles, and the balance of the metal oxide impurities.