A kaolin-based binder and its preparation method and application

Abstract

The present invention belongs to the technical field of inorganic binders, and provides a kaolin-based binder. The raw materials for preparing the kaolin-based binder include kaolin and phosphoric acid, and the mass ratio of kaolin to phosphoric acid is 100:(50-300). The present invention uses kaolin as a raw material and phosphoric acid as a binder to prepare a kaolin-based binder; kaolin is a clay and clay rock mainly composed of kaolinite clay minerals, which has a wide source, low cost, and strong acid resistance; kaolin can react chemically with phosphoric acid, and by controlling the mass ratio of phosphoric acid to kaolin, aluminum dihydrogen phosphate, aluminum monohydrogen phosphate and silica gel with strong bonding properties are generated. The results of the embodiment show that the compressive strength of the product made of the kaolin-based binder provided by the present invention, quartz sand and magnesium oxide is 11.59MPa.

Description

Technical Field

[0001] The invention relates to the technical field of inorganic binders, and in particular to a kaolin-based binder and a preparation method and application thereof. Background Art

[0002] Phosphate binder is a kind of building cementitious material. It is plastic before setting and hardening, and can be made into products of any size and shape according to requirements. It can be cured at room temperature or sintered at high temperature. It can be used with dispersants, curing agents, aggregates, etc. to make products like concrete. In addition, phosphate binder has high strength, high hardness, good water resistance, small curing shrinkage, environmental protection and non-toxicity, good construction performance, and strong adaptability to materials. Therefore, it is widely used in industrial and civil fields such as refractory materials, building materials, metal casting, inorganic coatings, composite materials, etc.

[0003] Common phosphate binders include aluminum dihydrogen phosphate and silicon phosphate. However, in the prior art, aluminum dihydrogen phosphate is usually prepared with high-quality alumina or aluminum hydroxide, which is costly and limits its application and promotion. In the prior art, silicon phosphate is usually prepared with quartz as the basic raw material and synthesized at high temperature (700-1000°C), which also has a high manufacturing cost. Therefore, it is urgent to solve the problem of high manufacturing cost of existing phosphate-based binders in order to realize the widespread application of phosphate binders. Summary of the invention

[0004] The purpose of the present invention is to provide a kaolin-based binder and a preparation method and application thereof. The kaolin-based binder provided by the present invention has low manufacturing cost and good bonding performance.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides a kaolin-based binder. The raw materials for preparing the kaolin-based binder include kaolin and phosphoric acid. The mass ratio of the kaolin to the phosphoric acid is 100:(50-300).

[0007] Preferably, the mass ratio of kaolin to phosphoric acid is 100:(50-180).

[0008] Preferably, the kaolin includes one or more of kaolin ore, kaolin concentrate, metakaolin and calcined kaolin.

[0009] Preferably, the phosphoric acid is added in the form of a phosphoric acid aqueous solution; the mass concentration of the phosphoric acid aqueous solution is 60-80%.

[0010] The present invention also provides a method for preparing the kaolin-based binder described in the above technical solution, comprising the following steps:

[0011] Phosphoric acid is mixed with kaolin to form green balls;

[0012] heat-sealing the raw balls to obtain cooked balls;

[0013] The cooked balls are crushed to obtain a kaolin-based binder.

[0014] Preferably, the heat sealing temperature is 50-200° C.; the heat sealing time is 30-180 min.

[0015] Preferably, after the pulverization, the process further comprises:

[0016] The powder obtained by the crushing is mixed with phosphoric acid to form a secondary ball;

[0017] performing a second heat sealing on the secondary balls to obtain secondary cooked balls;

[0018] The secondary cooked balls are crushed to obtain a kaolin-based binder.

[0019] Preferably, the mass ratio of the powder to phosphoric acid is 100:(60-180).

[0020] Preferably, the temperature of the second heat sealing is 500-1000° C.; the time of the second heat sealing is 30-180 min.

[0021] The present invention also provides the use of the kaolin-based binder described in the above technical solution or the kaolin-based binder prepared by the preparation method in the preparation of inorganic waste solidified bodies and water glass solidified bodies.

[0022] The present invention provides a kaolin-based binder, and the raw materials for preparing the kaolin-based binder include kaolin and phosphoric acid, and the mass ratio of kaolin to phosphoric acid is 100:(50-300). The present invention uses kaolin as a raw material and phosphoric acid as a binder to prepare a kaolin-based binder; kaolin is a clay and clay rock mainly composed of kaolinite clay minerals, which has a wide source, low cost, and strong acid resistance; kaolin can react chemically with phosphoric acid, and by controlling the mass ratio of phosphoric acid to kaolin, aluminum dihydrogen phosphate, aluminum monohydrogen phosphate and silica gel with strong bonding properties are generated. The results of the embodiment show that the compressive strength of the product made of the kaolin-based binder provided by the present invention, quartz sand and magnesium oxide is 11.59MPa.

[0023] The preparation method of the kaolin-based binder provided by the invention has simple operation and mild reaction conditions. DETAILED DESCRIPTION

[0024] The invention provides a kaolin-based binder. The raw materials for preparing the kaolin-based binder include kaolin and phosphoric acid. The mass ratio of the kaolin to the phosphoric acid is 100:(50-300).

[0025] In the present invention, the raw materials for preparing the kaolin-based binder include kaolin and phosphoric acid. The present invention uses kaolin as a raw material and phosphoric acid as a binder to prepare the kaolin-based binder; kaolin is a clay and clay rock mainly composed of kaolinite clay minerals, which has a wide source, low cost, and strong acid resistance; kaolin can react chemically with phosphoric acid to generate aluminum dihydrogen phosphate, aluminum monohydrogen phosphate and silica gel with strong bonding performance.

[0026] In the present invention, the mass ratio of kaolin to phosphoric acid is 100:(50-300), preferably 100:(50-180). The present invention can generate aluminum dihydrogen phosphate, aluminum monohydrogen phosphate and silica gel with strong bonding performance by controlling the mass ratio of phosphoric acid to kaolin.

[0027] In the present invention, the kaolin preferably includes one or more of kaolin ore, kaolin concentrate, metakaolin and calcined kaolin, and more preferably kaolin concentrate or metakaolin. The present invention has no particular limitation on the source of the kaolin, and commercial products well known to those skilled in the art can be used.

[0028] In the present invention, the grade of Al2O3 in the kaolin is preferably ≧35%; the particle size of the kaolin is preferably -0.074 mm, ≧95%; and the kaolin is preferably in powder form.

[0029] In the present invention, the phosphoric acid is preferably added in the form of a phosphoric acid aqueous solution; the mass concentration of the phosphoric acid aqueous solution is preferably 60 to 80%, more preferably 72 to 76%.

[0030] The present invention uses kaolin as a raw material and phosphoric acid as a binder to prepare a kaolin-based binder; kaolin can react chemically with phosphoric acid, and by controlling the mass ratio of phosphoric acid to kaolin, aluminum dihydrogen phosphate, aluminum monohydrogen phosphate and silica gel with strong bonding performance are generated.

[0031] The present invention also provides a method for preparing the kaolin-based binder described in the above technical solution, comprising the following steps:

[0032] Phosphoric acid is mixed with kaolin to form green balls;

[0033] heat-sealing the raw balls to obtain cooked balls;

[0034] The cooked balls are crushed to obtain a kaolin-based binder.

[0035] The invention mixes phosphoric acid and kaolin to form green balls.

[0036] In the present invention, the phosphoric acid is preferably heated before use. By heating the phosphoric acid, the phosphoric acid can be easily flowed, which is conducive to uniformly mixing kaolin and phosphoric acid. In the present invention, the heating temperature is preferably 45 to 90°C, more preferably 45 to 70°C.

[0037] The present invention has no particular limitation on the method of mixing and molding the phosphoric acid and kaolin, and any molding method known to those skilled in the art can be used. In the present invention, the molding equipment is preferably a roller pelletizer, a disc pelletizer or a drum granulator, and more preferably a drum granulator.

[0038] In the present invention, the diameter of the green balls is preferably 5 to 30 mm, more preferably 15 to 30 mm.

[0039] After obtaining the green balls, the present invention heat-seals the green balls to obtain cooked balls. The present invention heat-seals phosphoric acid and kaolin to react to generate a substance with strong bonding performance.

[0040] In the present invention, the heat sealing temperature is preferably 50-200°C, more preferably 100-150°C; the heat sealing time is preferably 30-180 min, more preferably 60-120 min. In the present invention, the heat sealing heating method is preferably direct heating or indirect heating; the heat sealing equipment is preferably an oven.

[0041] In the present invention, the following chemical reaction occurs between phosphoric acid and kaolin during the heat bonding process:

[0042] H3PO4+2SiO2·Al2O3·2H2O→Al(H2PO4)3+SiO2·nH2O

[0043] H3PO4+2SiO2·Al2O3·2H2O→Al2(HPO4)3+SiO2·nH2O

[0044] H3PO4+2SiO2·Al2O3·2H2O→AlPO4+SiO2·nH2O

[0045] After the cooked balls are obtained, the cooked balls are crushed to obtain a kaolin-based binder. The cooked balls are crushed to make kaolin-based binder powder, which is easy to use.

[0046] In the present invention, the pulverizing method is preferably grinding; the grinding method is preferably ball milling; and the equipment used for ball milling is preferably a ball mill.

[0047] In the present invention, the particle size of the kaolin-based binder obtained after pulverization is preferably -0.074 mm, ≧50%, and more preferably -0.074 mm, ≧95%.

[0048] In the present invention, the pulverizing preferably further comprises:

[0049] The powder obtained by the crushing is mixed with phosphoric acid to form a secondary ball;

[0050] performing a second heat sealing on the secondary balls to obtain secondary cooked balls;

[0051] The secondary cooked balls are crushed to obtain a kaolin-based binder.

[0052] In the present invention, the powder obtained by pulverizing is preferably mixed with phosphoric acid to form a secondary ball.

[0053] In the present invention, the mass ratio of the powder to phosphoric acid is preferably 100:(60-180), more preferably 100:(80-150). In the present invention, silicon phosphates of different compositions can be obtained by adjusting the mass ratio of phosphoric acid to the powder.

[0054] In the present invention, the mixing and forming method of the secondary balls is the same as the mixing and forming method of the raw balls, and will not be described in detail.

[0055] After obtaining the secondary balls, the present invention preferably performs a second heat sealing on the secondary balls to obtain secondary cooked balls. In the present invention, the second heat sealing temperature is preferably 500-1000°C, more preferably 700-800°C; the second heat sealing time is preferably 30-180 minutes, more preferably 60-120 minutes.

[0056] In the present invention, the powder and phosphoric acid undergo the following chemical reaction during the secondary heat bonding process:

[0057] H3PO4+SiO2→3SiO2·2P2O5+H2O

[0058] H3PO4+SiO2→SiO2·P2O5+H2O

[0059] In the present invention, the particle size of the kaolin-based binder obtained after pulverization is preferably -0.074 mm, ≧75%, and more preferably -0.074 mm, ≧95%.

[0060] The present invention preferably uses secondary heat sealing to react phosphoric acid with silicon dioxide in the powder to generate silicon phosphate, thereby further improving the bonding performance of the kaolin-based binder.

[0061] The invention can obtain the kaolin-based binder by sequentially mixing, molding, heat-sealing and crushing kaolin and phosphoric acid. The preparation method is simple to operate and the reaction conditions are mild.

[0062] The present invention also provides the use of the kaolin-based binder described in the above technical solution or the kaolin-based binder prepared by the preparation method in the preparation of inorganic solid waste solids and water glass solids.

[0063] The present invention uses a kaolin-based binder to prepare an inorganic waste solidified body, thereby effectively treating the inorganic waste and obtaining a high-strength solidified body.

[0064] In the present invention, the method for preparing the inorganic waste solidified body is preferably: mixing a kaolin-based binder with inorganic waste, adding water, and then casting and forming and standing for 2 days to obtain an inorganic waste solidified body. In the present invention, the inorganic waste preferably includes one or more of ceramic plates, refractory bricks, quartz sand, corundum powder, graphite and stone.

[0065] In the present invention, the raw materials for preparing the inorganic waste solidified body preferably further include one or more of an admixture, a dispersant, a curing agent and a reinforcing agent. In the present invention, the admixture, the dispersant, the curing agent and the reinforcing agent are preferably added when the kaolin-based binder and the inorganic waste are mixed.

[0066] In the present invention, the admixture preferably includes fly ash and / or blast furnace slag; the dispersant preferably includes phosphate and / or sodium polyacrylate; the curing agent preferably includes copper oxide and / or magnesium oxide; and the reinforcing agent preferably includes SiO2 and / or α-Al2O3.

[0067] The present invention uses a kaolin-based binder to prepare a water glass solidified body, and the obtained water glass solidified body has higher strength.

[0068] In the present invention, the preparation method of the water glass solidified body is preferably: solid waste, admixture, stabilizer, water glass and kaolin-based binder are added with water and stirred evenly, and then cast and formed and allowed to stand for 2 days to obtain the water glass solidified body.

[0069] In the present invention, the water glass solid body is preferably used to treat industrial solid waste or nuclear industry waste liquid; the industrial solid waste preferably includes mineral processing tailings, barium chemical slag or metallurgical waste slag; the nuclear industry waste liquid is preferably a waste liquid containing resin, borate or oleochemicals.

[0070] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0071] Example 1

[0072] 600g of phosphoric acid and 200g of powdered kaolin are mixed evenly (the mass ratio of kaolin to phosphoric acid is 100:300), and raw balls of 15-30mm are formed by a drum granulator. The raw balls are placed in an oven, heated to 145°C and kept warm for 150 minutes to obtain cooked balls; the cooled cooked balls are ball-milled to -0.074mm, ≧95% of powder, which is a kaolin-based binder.

[0073] Application Example 1

[0074] 200 g of quartz sand, 40 g of the kaolin-based binder prepared in Example 1 and 6 g of magnesium oxide were mixed and crushed, and then 36.9 mL of deionized water was added, mixed well, and allowed to stand for 2 days to obtain a solid body. The weight loss rate of the solid body was measured to be 0.93%, and the compressive strength was 11.59 MPa.

[0075] Application Example 2

[0076] 200 g of quartz sand, 40 g of the kaolin-based binder prepared in Example 1 and 6 g of magnesium oxide were mixed and crushed, and 36.9 mL of deionized water was added and mixed well. After standing for 2 days, it was placed in a constant temperature drying oven at 165°C and kept warm for 2 hours to obtain a solid body. The weight loss rate of the solid body was measured to be 14.30%, and the compressive strength was 12.58 MPa.

[0077] Application Example 3

[0078] 200g of quartz sand, 50g of kaolin-based binder prepared in Example 1, 7.5g of magnesium oxide and 10.2g of uranium-containing waste rock were mixed and crushed, 32.1mL of deionized water was added, mixed well, and placed in a 175°C constant temperature drying oven for 2 hours after standing for 2 days to obtain a solidified body, and the weight loss rate of the solidified body was measured to be 17.06%. The solidified body was crushed to -200 mesh, soaked in distilled water for 6 days, and the uranium leaching rate was measured to be 0.68%. After soaking for another 2 days, the uranium leaching rate did not increase.

[0079] Example 2

[0080] 400g of phosphoric acid and 200g of powdered kaolin are mixed evenly (the mass ratio of kaolin to phosphoric acid is 100:200), and raw balls of 15-30mm are formed by a drum granulator. The raw balls are placed in an oven, heated to 145°C and kept warm for 150 minutes to obtain cooked balls; the cooled cooked balls are ball-milled to -0.074mm, ≧95% of powder, which is a kaolin-based binder.

[0081] Application Example 4

[0082] 200 g of quartz sand, 40 g of the kaolin-based binder prepared in Example 2 and 6 g of magnesium oxide were mixed and crushed, and then 36.9 mL of deionized water was added, mixed well, and allowed to stand for 2 days to obtain a solid body. The weight loss rate of the solid body was measured to be 3.3%.

[0083] Example 3

[0084] 200g of phosphoric acid and 200g of powdered kaolin are mixed evenly (the mass ratio of kaolin to phosphoric acid is 100:100), and raw balls of 15-30mm are formed by a drum granulator. The raw balls are placed in an oven, heated to 145°C and kept warm for 150 minutes to obtain cooked balls; the cooled cooked balls are ball-milled to -0.074mm, ≧95% of powder, which is a kaolin-based binder.

[0085] Application Example 5

[0086] 200 g of quartz sand, 40 g of the kaolin-based binder prepared in Example 3 and 6 g of magnesium oxide were mixed and crushed, and then 36.9 mL of deionized water was added, mixed well, and allowed to stand for 2 days to obtain a solid body. The weight loss rate of the solid body was measured to be 13.37%.

[0087] Example 4

[0088] 600g of phosphoric acid and 200g of powdered kaolin were mixed evenly (the mass ratio of kaolin to phosphoric acid was 100:300), and raw balls of 15-30mm were made by a drum granulator. The raw balls were placed in an oven, heated to 145°C and kept warm for 150min to obtain cooked balls; the cooled cooked balls were ball-milled to -0.074mm, ≧95% of powder;

[0089] The above powder is mixed evenly with 480g of phosphoric acid (the mass ratio of powder to phosphoric acid is 100:60), and secondary balls of 15-30mm are formed by a drum granulator. The secondary balls are placed in an oven, heated to 800°C and kept warm for 120min to obtain secondary cooked balls; the cooled secondary cooked balls are ball-milled to -0.074mm, ≧95% of the powder, which is a kaolin-based binder.

[0090] Application Example 6

[0091] 200 g of quartz sand, 40 g of the kaolin-based binder prepared in Example 4, and 6 g of magnesium oxide were mixed and crushed, and then 36.9 mL of deionized water were added, mixed well, and allowed to stand for 2 days to obtain a solidified body.

[0092] It can be seen from the above examples that the kaolin-based binder provided by the present invention has low manufacturing cost and good bonding performance, and the compressive strength of the product made with quartz sand and magnesium oxide is 11.59 MPa.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a kaolin-based binder, wherein the raw materials for preparing the kaolin-based binder are composed of kaolin and phosphoric acid, and the mass ratio of kaolin to phosphoric acid is 100:(50-300); The phosphoric acid is added in the form of a phosphoric acid aqueous solution; the mass concentration of the phosphoric acid aqueous solution is 60-80%; The preparation method of the kaolin-based binder comprises the following steps: Phosphoric acid is mixed with kaolin to form green balls; The phosphoric acid is heated before use, and the heating temperature is 45-90° C.; Heat-sealing the raw balls to obtain cooked balls; the heat-sealing temperature is 145° C. and the heat-sealing time is 150 minutes; The cooked balls are crushed to obtain a kaolin-based binder.

2. The preparation method according to claim 1, characterized in that: The mass ratio of kaolin to phosphoric acid is 100:(50-180).

3. The preparation method according to claim 1, characterized in that: The kaolin includes one or more of kaolin ore, kaolin concentrate, metakaolin and calcined kaolin.

4. The preparation method according to claim 1, characterized in that: The crushing also includes: The powder obtained by the crushing is mixed with phosphoric acid to form a secondary ball; performing a second heat sealing on the secondary balls to obtain secondary cooked balls; The secondary cooked balls are crushed to obtain a kaolin-based binder.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the powder to phosphoric acid is 100:(60-180).

6. The preparation method according to claim 4, characterized in that: The temperature of the second heat sealing is 500-1000° C.; the time of the second heat sealing is 30-180 minutes.

7. Use of a kaolin-based binder prepared by the preparation method according to any one of claims 1 to 6 in the preparation of inorganic waste solids and water glass solids.