CN108855152A - Catalyst for improving soluble aluminum content of calcium aluminate powder and application method thereof - Google Patents

Abstract

The present invention proposes a catalyst for increasing the soluble aluminum content of calcium aluminate powder and its application method. The soluble alumina content of calcium aluminate powder can be increased through the addition of external agents, thereby improving the product quality of existing calcium aluminate powder. Improve market competitiveness. The present invention is prepared in the following manner: 72%wt of sodium fluorosilicate, 11%wt of sodium chloride, 11%wt of plant ash and 6%wt of sodium fluoroaluminate are weighed and then ground during grinding for 5 ‑8 minutes to fully mix the four substances to obtain a composite catalyst. This application uses the existing bauxite, limestone and other raw materials of calcium aluminate powder production enterprises, plus a small amount of cheap aluminum-containing substances and catalysts, and the soluble alumina content of calcium aluminate powder can be increased through the addition of external agents, thereby improving It has the product quality of calcium aluminate powder and improves market competitiveness.

Description

Catalyst for increasing soluble aluminum content of calcium aluminate powder and method of application thereof

technical field

The present invention relates to the production field of calcium aluminate powder, be specifically related to a kind of method that the soluble aluminum oxide content of calcium aluminate powder is improved by the adding of external medicament.

Background technique

Calcium aluminate powder is an ideal raw material for the production of basic aluminum chloride and polyaluminum chloride products. The main components are CaO, AL ₂ O ₃ , Fe ₂ O ₃ , which have strong activity. Using acid-soluble one-step method to produce water purifier can save a lot of manpower and electricity, and can greatly reduce costs, and has simple process equipment , Easy to master and other advantages. In recent years, the problem of global water pollution has become increasingly prominent and has become a severe challenge faced by many countries.

The production of calcium aluminate powder usually uses high-grade bauxite with an alumina content of about 65%-70% and limestone with a calcium carbonate content of about 95%. The ratio of the two is designed according to the reaction equation generated by calcium aluminate powder. Bauxite: Limestone = about 100:175, which can be obtained by crushing and grading after burning in the temperature range of 1250-1350°C.

Most of the bauxite resources in my country are diaspore types with high aluminum, high silicon and low aluminum-silicon ratio. Different from other regions in the world, more than 95% of my country's bauxite is diaspore type, and this type of bauxite belongs to medium grade. At present, the reserves of high-quality bauxite resources are becoming less and less. The development and utilization of medium and low-grade bauxite (alumina grade between 55-60%wt) to prepare calcium aluminate powder water purifier materials has broad market prospects.

Three kinds of bauxite raw materials used in the production of the enterprise were collected, and the test results are as follows in Table 1: From Table 1, it can be known that the alumina grades of the three kinds of bauxite are slightly higher, Bau-1 and Bau-2, at 55-60% between wt. According to the national standard GBT 24483-2009, the bauxite ore standard should be compared with the DLK11-55 grade, but the national standard requires that the aluminum-silicon ratio of this grade should be at least greater than 11, so Bau-1 and Bau-2 are both unqualified bauxite ores , Bau-3 alumina grade and aluminum-silicon ratio are even worse.

Table 1 Chemical analysis results of main elements of bauxite samples

The content of total alumina in the calcium aluminate powder prepared by using the above-mentioned medium and low-grade bauxite is about 45%. According to the method introduced in the national standard GBT 29341-2012 Calcium Aluminate for Water Treatment Agents, the acid dissolution test was carried out on the calcium aluminate products of the company, and the chemical analysis shows that the content of soluble alumina in the calcium aluminate products is about 39.5%. .

Contents of the invention

The present invention proposes a catalyst for increasing the soluble aluminum content of calcium aluminate powder and its application method. The soluble alumina content of calcium aluminate powder can be increased through the addition of external agents, thereby improving the product quality of existing calcium aluminate powder. Improve market competitiveness.

The technical solution of the present invention is realized in the following manner: a catalyst for improving the soluble aluminum content of calcium aluminate powder is prepared in the following manner: 72%wt of sodium fluorosilicate, 11%wt of chlorinated Sodium, 11%wt of plant ash and 6%wt of sodium fluoroaluminate are weighed and then ground for 5-8 minutes during grinding to fully mix the four substances to obtain a composite catalyst.

The application method of the composite catalyst is carried out according to the following steps: according to the amount of raw meal powder, the ground waste alumina powder of the addition of 4%wt, the composite catalyst of the addition of 3%wt and The tap water is fully stirred to become a suspension, which is added dropwise to the surface of the raw meal powder, and the raw meal powder is fully stirred to make it evenly mixed, and then the pellets are formed, and then put into the muffle furnace for calcination.

Preferably, the waste alumina is a powder that can pass through a 325-mesh sieve after grinding.

The catalyst is added to waste alumina in an amount of 10%wt, ground in a ball mill tank with water, and then the pulp is washed out, dried and pulverized to obtain a supported catalyst.

The application method of the supported catalyst is carried out according to the following steps: according to the amount of raw meal powder, mix the supported catalyst of 4% wt with tap water, stir the slurry to a suspension state, drop by drop The suspension is added dropwise to the surface of the raw meal powder, and the raw meal powder is fully stirred to make it evenly mixed, then formed into pellets, and put into a muffle furnace for calcination.

This application uses the existing bauxite, limestone and other raw materials of calcium aluminate powder production enterprises, plus a small amount of cheap aluminum-containing substances and catalysts, and the soluble alumina content of calcium aluminate powder can be increased through the addition of external agents, thereby improving It has the product quality of calcium aluminate powder and improves market competitiveness.

Detailed ways

A catalyst for improving the soluble aluminum content of calcium aluminate powder is prepared in the following manner: 72%wt of sodium fluorosilicate, 11%wt of sodium chloride, 11%wt of plant ash and 6%wt of After the sodium fluoroaluminate is weighed, grind for 5-8 minutes during grinding (5-8 minutes during grinding in a three-head grinder), so that the four substances are fully mixed to obtain a composite catalyst. Its use process is as follows: According to raw meal powder (raw meal powder is the material prepared during actual production, the specific mass ratio of each component is about: bauxite: limestone: coal = 50:35:15, coal is added to the main In order to provide energy in the calcining process), the amount of ground waste alumina powder added in an amount of 4%wt, the composite catalyst added in an amount of 3%wt and tap water were fully stirred to become a suspension, and added dropwise On the surface of the raw meal powder, fully stir the raw meal powder to make it evenly mixed, then form a pellet, and put it into a muffle furnace for calcination.

Preferably, the waste alumina (referring to the unqualified alumina produced by alumina production enterprises and the ground materials produced during production and transportation) is the powder that can pass through the 325 mesh screen after grinding.

In the present application, the principle of the catalyst is as follows: 1. The non-metallic ionic functional group has a lower boiling point and is easy to melt/gasify in a high-temperature reaction. The sintering temperature is increased, and defects occur in the crystal lattice of insoluble aluminum, thereby increasing the dissolution rate of aluminum. 2. The catalyst can inhibit the generation of spinel phase with higher lattice activation energy, thereby reducing the generation of insoluble aluminum.

This application also discloses a supported catalyst, which is prepared in the following manner: add the above-mentioned composite catalyst to waste alumina in an amount of 10%wt, add water to grind in a ball mill tank, and then wash out the pulp Dry powder to obtain the supported catalyst. Its use method is as follows: according to the amount of raw meal powder, mix 4%wt of the supported catalyst with tap water, stir the slurry to a suspension state, drop the suspension onto the surface of the raw meal powder, Thoroughly stir the raw meal powder to make it evenly mixed, then form a pellet, and put it into a muffle furnace for calcination.

The catalyst of the present application can obviously increase the soluble alumina content of calcium aluminate clinker powder, and has better economic cost. It can be divided into composite type and supported type according to the compounding form of aluminum source and catalyst. This type of catalyst can stably increase the soluble alumina of calcium aluminate clinker powder no matter under laboratory conditions or under enterprise field conditions. The content is 2-4%. The materials and test equipment used to prepare the catalyst are listed in Table 2.

Table 2 Information list of materials and equipment required for the preparation of composite catalysts

serial number name Specifications manufacturers Function 1 Waste alumina powder -- Provided by the enterprise Catalyst Aluminum Source 2 Sodium fluorosilicate Analytical pure Sinopharm Reagent Catalyst component 3 Sodium chloride Analytical pure Sinopharm Reagent Catalyst component 4 plant ash commercially available Sinopharm Reagent Catalyst component 5 Sodium fluoroaluminate Analytical pure Sinopharm Reagent Catalyst component 6 Electronic balance BSA124S Sartorius weighing tool 7 Three-head grinder Catalyst processing 8 planetary ball mill Catalyst processing 9 Blast drying oven 101A-2 Shanghai experimental equipment for drying 10 High speed pulverizer 6202 Huanya Tianyuan Machinery for powder

Embodiment 1: First, the waste alumina powder is ground, and the grinding condition is to weigh 15-20 g of the waste alumina sample with an electronic balance, and add it to a mortar of a three-head grinder for continuous grinding for 15 minutes, and the ground alumina The powder should all pass through a 325 mesh screen. Grinding waste alumina can effectively reduce the mesh size of this aluminum source, while increasing its specific surface area and surface activity.

Then prepare the composite catalyst component, first accurately weigh the sodium fluorosilicate of 72%wt and then weigh the sodium chloride of 11%wt respectively, the plant ash of 11%wt and the sodium fluoroaluminate of 6%wt (four kinds The total amount of ingredients is 100%wt), and after the weighing is completed, add it into the grinding of the three-head grinder and grind for 5-8 minutes, so that the four substances are fully mixed. Finally, pack and seal the ground catalyst powder for use.

Based on raw meal powder addition 50g, the preparation method of the corresponding composite catalyst is: accurately weigh 2.0g (4% addition) waste alumina powder ground and add in the beaker, then weigh the prepared catalyst 1.5g ( 3% added amount) into the beaker. Add tap water and stir well to become a suspension, add drop by drop to the surface of the raw meal powder through a dropper, mix the raw meal powder thoroughly to form a pellet, put it into a muffle furnace and calcinate according to the process conditions That's it. The specific formulation summary is shown in Table 3.

Table 3 Composite catalyst formula table

Example 2: In order to make the catalyst more efficient in use and easier to prepare and add, this example uses the principle of mechanochemistry to produce a supported catalyst.

The preparation method of the supported catalyst is as follows: respectively weigh 55g of waste alumina powder (unground) and 5.5-6g of the composite catalyst prepared in Example 1 (the relative addition amount is about 10%wt), and put them into a 500ml ceramic ball mill jar And add 60g of water, seal tightly and put it into a position of the planetary mill, and put a counterweight tank of the same weight in its symmetrical position. Use a wrench to fix the two ball mill jars tightly and then start grinding. The ball mill speed is set to 800rpm, and the grinding time is set to 30 minutes. After the grinding is completed, the ore slurry is washed out and then dried and powdered for subsequent tests.

Take 50g of raw meal powder to test this type of catalyst as an example, directly weigh 2g of the prepared supported catalyst (4%wt addition) and put it into a beaker, add an appropriate amount of tap water to stir the slurry to a suspension state, use drops Add the catalyst liquid to the surface of the raw meal powder drop by drop through the tube, mix the raw meal powder evenly and then form a pellet, put it into the muffle furnace and calcinate according to the process conditions.

The basic principle of this embodiment is: use the huge mechanical extrusion force and centrifugal force produced by the planetary ball mill during the grinding process to make the composite catalyst and the aluminum source fully squeeze and infiltrate during the grinding process, so that the aluminum source is in the grinding process. At the same time, the catalyst agent contaminates the surface of the aluminum source powder, so that the loading method of the catalyst changes from the previous bulk phase catalysis to surface catalysis, which can greatly save the amount of catalyst with high cost.

Composite catalysts and supported catalysts were used for testing respectively. Each catalyst was put into a parallel sample without catalyst as a comparison during the test. Each sample uses 60g of raw meal powder, and the use of composite catalysts requires the addition of 1.8g of catalyst and 2.4g of waste alumina. Use supported catalyst then need to add catalyst 2.4g.

Embodiment 1 and embodiment 2 use method as follows:

A muffle furnace with a set temperature curve or a muffle furnace with manual temperature control can be used. The heating process of the muffle furnace in this application is as follows: first dry the agglomerated wet material at 150°C for 30 minutes, and then transfer to the upper limit of 1100°C The muffle furnace was calcined at 580°C for 30 minutes, and then heated to 900°C for 30 minutes; finally, the sample was transferred to the muffle furnace with an upper limit of 1600°C and set at the set temperature (1250°C--1350°C ) sintered for 40 minutes, and obtained clinker after cooling.

After the obtained clinker was sieved by vibrating mill, 15g sample was weighed and boiled at 100°C for 60 minutes with 100ml hydrochloric acid, 8ml filter aid was added to the filtrate, stirred and filtered to obtain the filtrate. Finally, the laboratory personnel use the determination method of soluble alumina in the measurement of soluble alumina content introduced in the national standard GB/T29341-2012 "Determination of soluble alumina" to perform titration analysis on the leachate to be tested and calculate the soluble alumina content.

Experimental comparisons of four batches were performed, each batch containing a blank and a catalyst-containing sample. The specific test conditions and results are summarized in Table 4.

Table 4 Test Catalyst Test Results Summary Table

From the test results in Table 4, it can be seen that at 1350°C, the sample was melted and damaged due to the high temperature, and at 1200°C, the soluble alumina content of the composite catalyst was low due to the low test temperature. Under the condition of 1250℃, the supported catalyst can increase the content of soluble alumina by 1.5%, and the composite catalyst can increase the content of soluble alumina by more than 4%.

Table 5 Summary table of calcium aluminate sintering experiment results

It can be seen from Table 5 that after adding the catalyst, the content of soluble aluminum increased significantly.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (5)

1. A catalyst for improving the soluble aluminum content of calcium aluminate powder is characterized in that it is prepared in the following manner: the sodium fluorosilicate of 72%wt, the sodium chloride of 11%wt, the plant ash of 11%wt After weighing with 6% wt of sodium fluoroaluminate, grind for 5-8 minutes during grinding, so that the four substances are fully mixed to obtain a composite catalyst. 2. the catalyzer of improving the soluble aluminum content of calcium aluminate powder according to claim 1 is characterized in that: described catalyzer is added in waste alumina according to the addition amount of 10%wt, adds water and grinds in ball mill jar, after that After the pulp is washed out, it is dried and pulverized to obtain a supported catalyst. 3. a kind of application method of catalyzer as claimed in claim 1, it is characterized in that carry out according to the following steps: according to the amount of raw meal powder, the spent aluminum oxide powder that the addition of 4%wt is ground, 3%wt composite catalyst and tap water are fully stirred to form a suspension, which is added dropwise to the surface of the raw meal powder, and the raw meal powder is fully stirred to make it evenly mixed, and then the pellets are formed and put into the muffle furnace Can be calcined. 4. The application method of the catalyst according to claim 3, characterized in that: the waste alumina is a powder that can pass through a 325-mesh sieve after grinding. 5. a kind of application method of catalyzer as claimed in claim 2 is characterized in that being carried out according to the following steps: according to the amount of raw meal powder, the loaded catalyst of 4%wt addition is mixed with tap water, stirring material When the slurry is in the state of suspension, add the suspension to the surface of the raw meal powder drop by drop, fully stir the raw meal powder to make it evenly mixed, and then form a pellet, then put it in the muffle furnace for calcination.