Calcium silicate board of nickel-iron acid leaching residue and preparation method thereof

Abstract

The application discloses a calcium silicate board of nickel-iron acid leaching slag, which comprises nickel-iron acid leaching slag, calcareous raw material and reinforcing fiber; and according to the total mass of the nickel-iron acid leaching slag and the calcareous raw material being 100%, the mass of the nickel-iron acid leaching slag accounts for 50-80%, and the mass of the calcareous raw material accounts for 20-50%; the nickel-iron acid leaching slag is obtained by pretreatment of nickel-iron slag, which comprises acid solution soaking and solid-liquid separation. The application discloses a preparation method of the calcium silicate board of the nickel-iron acid leaching slag. The calcium silicate board is prepared by using the nickel-iron acid leaching slag, the calcareous raw material and the reinforcing fiber, a large amount of nickel-iron slag can be consumed, and the nickel-iron slag is used in a reduced amount and high value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of comprehensive utilization of solid waste resources, and particularly relates to a calcium silicate board of nickel-iron acid leaching residue and a preparation method thereof. BACKGROUND

[0002] Nickel-iron slag is an industrial solid waste discharged in the process of smelting nickel-iron alloy. With the gradual expansion of the smelting scale of nickel-iron alloy in China, the discharge amount of nickel-iron slag is also gradually increasing. The annual discharge amount of nickel-iron slag in Guangdong Province has exceeded one million tons. However, the comprehensive utilization degree of nickel-iron slag is low at present. For example, the comprehensive utilization rate of nickel-iron slag in Guangdong Province is only about 20%. Most of the nickel-iron slag is still treated by stacking, which leads to the penetration of heavy metal nickel ions into groundwater and soil with rainwater, occupies land, and causes certain influence on the surrounding environment. If not properly disposed, it will become a potential environmental hazard.

[0003] The chemical composition of nickel-iron slag is mainly SiO2, MgO and Fe2O3. The content of MgO is often as high as more than 25%, which belongs to typical high-magnesium solid waste. The mineral composition is mainly forsterite phase, and the proportion is as high as 75%. Nickel-iron slag has the characteristics of low activity, poor stability, few comprehensive utilization channels and high utilization cost.

[0004] The calcium silicate board is a board made of siliceous material and calcareous material as main raw materials, or by adding other auxiliary materials, through the processes of mixing, pulping, pressing, forming, autoclave curing and the like. The calcium silicate board has the advantages of fireproof, moistureproof, sound insulation, heat insulation and the like, and is widely used in the fields of fireproof partition board, ceiling board, fireproof door and the like of high-rise and public buildings. SUMMARY

[0005] One of the purposes of the present application is to provide a calcium silicate board of nickel-iron acid leaching residue, which meets the standard requirements of JC / T564.1-2018 "Fiber Reinforced Calcium Silicate Board Part 1: Non-asbestos Calcium Silicate Board", and realizes the reduction and high-value utilization of nickel-iron slag.

[0006] The second purpose of the present application is to provide a preparation method of the above-mentioned calcium silicate board.

[0007] The first purpose of the present application is achieved by the following technical scheme:

[0008] A calcium silicate board of nickel-iron acid leaching residue, characterized in that it comprises nickel-iron acid leaching residue, calcareous raw material and reinforcing fiber; and according to the total mass of the nickel-iron acid leaching residue and the calcareous raw material being 100%, the mass of the nickel-iron acid leaching residue accounts for 50-80%, and the mass of the calcareous raw material accounts for 20-50%.

[0009] The nickel-iron acid leaching residue is obtained by pretreatment including acid solution soaking and solid-liquid separation.

[0010] The nickel-iron acid leaching residue of the present application is a secondary residue produced by acid leaching and solid-liquid separation of nickel-iron residue, and the mechanism is that under acidic conditions, the metal cations on the surface of forsterite and silicate groups are dissolved, the Mg-O bond is broken, magnesium ions are dissolved into the solution, and valuable metal ions such as nickel ions and iron ions are also leached into the solution in large amounts, so that the obtained nickel-iron acid leaching residue is a high-quality siliceous raw material mainly composed of highly concentrated SiO2. Through a large number of experiments, it is determined that the calcium silicate board prepared by taking the nickel-iron acid leaching residue and calcium raw material as the main material and the reinforcing fiber as the auxiliary raw material meets the standard requirements in performance indicators.

[0011] Further, the calcium raw material of the present application is one or more of lime, phosphogypsum and carbide slag, and the effective CaO content is not less than 85%, and the fineness is greater than 250 mesh.

[0012] The above-mentioned lime is a calcium-containing inorganic material mainly composed of oxides and hydroxides; the phosphogypsum is a by-product of the phosphating industry; and the carbide slag is a waste residue mainly composed of calcium hydroxide after hydrolysis of calcium carbide to obtain acetylene gas.

[0013] Further, the reinforcing fiber of the present application is one or more of glass fiber, cellulose and periclase fiber, and the addition amount is 5-8% of the total mass of the nickel-iron acid leaching residue and the calcium raw material.

[0014] Specifically, the pretreatment process of the present application is as follows: after the nickel-iron residue is ground into a powder with a specific surface area of 350-420 kg / m 3 , the powder is placed in an acid solution with a pH value of 2-3 at a solid-liquid mass ratio of 1:10, and then soaked at room temperature for 28-180 days, and then the mixture is subjected to solid-liquid separation, and the separated solid is washed with water to obtain the nickel-iron acid leaching residue.

[0015] Further, the acid solution in the pretreatment process is a strong acid solution, which can be one or more of hydrochloric acid, sulfuric acid and nitric acid.

[0016] Further, the calcium silicate board of the present application further comprises an additive.

[0017] The additive includes a flocculating agent, a defoaming agent and a pigment; the present application does not have special limitations on the addition amount of the additive, and the conventional amount can be used.

[0018] The second object of the present application is achieved by the following technical scheme:

[0019] A preparation method of a calcium silicate board of a nickel-iron acid leaching residue, comprising the following steps:

[0020] (1) pulp preparation: weigh the nickel-iron acid leaching residue, calcium raw material, reinforcing fiber and additive, and mix them with water to prepare a slurry;

[0021] (2) Green body forming: the slurry is formed into a plate by a flow slurry method, and a press is used for pressing to obtain a formed plate;

[0022] (3) Pre-curing: the formed plate is demolded after pre-curing;

[0023] (4) Autoclave curing: the plate after pre-curing is placed in an autoclave for autoclave curing;

[0024] (5) Finished product: the plate after autoclave curing is dried to obtain the calcium silicate plate.

[0025] In step (1), the water content of the slurry is controlled to be 30-40%.

[0026] In step (2), a 300t press is used for pressing for 1-2h, so that the water content of the plate is reduced to 5-10%.

[0027] In step (3), the plate is demolded after pre-curing at 30-80℃ for 3-7h.

[0028] In step (4), the temperature of the autoclave curing is 120-150℃, the steam pressure is 0.8-1.5MPa, and the autoclave curing time is 8-15h.

[0029] In step (5), the plate is dried for 2-4h.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] (1) The present application makes full use of the fact that magnesium ions, nickel ions and iron ions are leached out from the nickel-iron slag in an acidic environment, and a nickel-iron acid leaching slag mainly containing highly polymerized SiO2 is obtained; the calcium silicate plate prepared by using the slag, calcium raw materials and reinforcing fibers meets the standard requirements in performance indexes.

[0032] (2) The calcium silicate plate prepared by the present application can consume a large amount of industrial waste slag of nickel-iron slag, phosphogypsum and carbide slag, realizes the resource utilization of industrial solid waste, reduces the harm to the environment, has significant economic benefits and environmental effects, and is conducive to the sustainable development of enterprises.

[0033] (3) The preparation process of the present application is simple, the production cost is low, the production cycle is short, the calcium silicate plate prepared has a bending strength of more than 15MPa, has good fireproof and heat insulation properties, and can be widely used in building engineering. DETAILED DESCRIPTION

[0034] The following examples are used to illustrate the present application, but the scope of protection of the present application is not limited to the following examples. The person skilled in the art can achieve the purpose of the present application according to the above disclosure and the range of parameters.

[0035] Example 1

[0036] The raw material addition amount of the calcium silicate board of the present example is: nickel-iron acid leaching residue 50%, lime 50%, and alkaline glass fiber is added in an amount of 5% of the total mass of the nickel-iron acid leaching residue and lime;

[0037] The nickel-iron acid leaching residue is pretreated as follows: after the nickel-iron slag is ground to a specific surface area of 350 kg / m 3 , the solid-liquid mass ratio is 1:10, and the mixture is placed in an acid solution with a pH value of 2 at room temperature for 28 days of standing and soaking, and then the mixture is subjected to solid-liquid separation, and the separated solid is washed with water.

[0038] The preparation method of the calcium silicate board of the present example comprises the following steps:

[0039] (1) Slurry preparation: the nickel-iron acid leaching residue, calcium raw material, and reinforcing fiber are weighed according to the above proportions and mixed with water to prepare a slurry, and the water content of the slurry is controlled at 30%;

[0040] (2) Green body forming: the slurry is used to make a board by the flow slurry method, and a 300t press is used to press for 1h, so that the water content of the green body is reduced to 5%;

[0041] (3) Pre-curing: after the green body is formed, it is demolded after pre-curing at 30℃ for 3h;

[0042] (4) Autoclave curing: the pre-cured green body is placed in an autoclave for autoclave curing; the temperature of the autoclave curing is 120℃, the time of the autoclave curing is 8h, and the steam pressure of the autoclave curing is 0.8MPa;

[0043] (5) Finished product: the autoclave-cured green body is dried for 2h to obtain the calcium silicate board.

[0044] Example 2

[0045] The raw material addition amount of the calcium silicate board of the present example is: nickel-iron acid leaching residue 60%, phosphogypsum 40%, and alkaline glass fiber is added in an amount of 6% of the total mass of the nickel-iron acid leaching residue and phosphogypsum;

[0046] The nickel-iron acid leaching residue is pretreated as follows: after the nickel-iron slag is ground to a specific surface area of 350 kg / m 3After the powder is obtained, the powder is placed in an acid solution with a pH value of 2 at a solid-liquid mass ratio of 1:10, and is soaked at room temperature for 56 days, and then the mixture is subjected to solid-liquid separation, and the separated solid is washed with water.

[0047] The preparation method of the calcium silicate board of the embodiment includes the following steps:

[0048] (1) Slurry preparation: the nickel-iron acid leaching residue, calcium raw material, and reinforcing fiber are weighed according to the above-mentioned proportions, mixed with water to prepare a slurry, and the water content of the slurry is controlled at 35%;

[0049] (2) Green body forming: a flow slurry method is used to prepare a board, and a 300t press is used to press for 1.5h, so that the water content of the board blank is reduced to 7%;

[0050] (3) Pre-curing: after the board blank is formed, it is demolded after pre-curing at 50℃ for 4h;

[0051] (4) Autoclave curing: the pre-cured board blank is placed in an autoclave for autoclave curing, wherein the temperature of the autoclave curing is 130℃, the time of the autoclave curing is 10h, and the steam pressure of the autoclave curing is 1.0MPa;

[0052] (5) Finished product: the autoclave-cured board blank is dried for 2h to obtain the calcium silicate board.

[0053] Example 3

[0054] According to the mass percentage, the raw material addition amount of the calcium silicate board of the embodiment is: nickel-iron acid leaching residue 70%, carbide slag 30%, and cellulose addition amount is 7% of the total mass of the nickel-iron acid leaching residue and the calcium raw material;

[0055] The nickel-iron acid leaching residue is subjected to the following pretreatment process: the nickel-iron residue is ground to a specific surface area of 400kg / m 3 After the powder is obtained, the powder is placed in an acid solution with a pH value of 2 at a solid-liquid mass ratio of 1:10, and is soaked at room temperature for 84 days, and then the mixture is subjected to solid-liquid separation, and the separated solid is washed with water.

[0056] The preparation method of the calcium silicate board of the embodiment includes the following steps:

[0057] (1) Slurry preparation: the nickel-iron acid leaching residue, calcium raw material, and reinforcing fiber are weighed according to the above-mentioned proportions, mixed with water to prepare a slurry, and the water content of the slurry is controlled at 35%;

[0058] (2) Green body forming: a flow slurry method is used to prepare a board, and a 300t press is used to press for 2h, so that the water content of the board blank is reduced to 10%;

[0059] (3) Pre-curing: after the board blank is formed, it is demolded after pre-curing at 60℃ for 6h;

[0060] (4) Autoclaved curing: the pre-cured green body is placed in an autoclave for autoclaved curing, wherein the temperature of the autoclaved curing is 140 ℃, the time of the autoclaved curing is 12 h, and the steam pressure of the autoclaved curing is 1.2 MPa;

[0061] (5) Finished product: the autoclaved green body is dried for 2 h to obtain the calcium silicate board.

[0062] Example 4

[0063] According to the mass percentage, the raw material addition amount of the calcium silicate board of the present example is: nickel-iron acid leaching residue 80%, lime 10%, phosphor gypsum 10%, and the addition amount of alkaline glass and fibrous magnesite fiber is 4% of the total mass of the nickel-iron acid leaching residue and the calcareous raw material (i.e. the addition amount of the reinforcing fiber is 8% of the total mass of the nickel-iron acid leaching residue and the calcareous raw material);

[0064] The nickel-iron acid leaching residue is pretreated by the following process: the nickel-iron residue is ground to a specific surface area of 350 kg / m 3 of powder, and then placed in an acid solution with a pH value of 3 at a solid-liquid mass ratio of 1:10, and soaked at room temperature for 112 days. Then the mixture is subjected to solid-liquid separation, and the separated solid is washed with water.

[0065] The preparation method of the calcium silicate board of the present example comprises the following steps:

[0066] (1) Slurry preparation: the nickel-iron acid leaching residue, the calcareous raw material, and the reinforcing fiber are weighed according to the above proportions, mixed with water to prepare a slurry, and the water content of the slurry is controlled at 40%;

[0067] (2) Green body forming: the slurry is used to form a board by the flow slurry method, and a 300 t press is used to pressurize for 1.5 h, so that the water content of the green body is reduced to 9%;

[0068] (3) Pre-curing: the green body is demolded after pre-curing at 60 ℃ for 7 h;

[0069] (4) Autoclaved curing: the pre-cured green body is placed in an autoclave for autoclaved curing, wherein the temperature of the autoclaved curing is 150 ℃, the time of the autoclaved curing is 15 h, and the steam pressure of the autoclaved curing is 1.5 MPa;

[0070] (5) Finished product: the autoclaved green body is dried for 4 h to obtain the calcium silicate board.

[0071] Example 5

[0072] According to the mass percentage, the raw material addition amount of the calcium silicate board of the present example is: nickel-iron acid leaching residue 60%, phosphor gypsum 20%, carbide slag 20%, and the addition amount of alkaline glass fiber is 6% of the total mass of the nickel-iron acid leaching residue and the calcareous raw material.

[0073] The nickel-iron acid leaching residue is pretreated by the following process: the nickel-iron residue is ground into a powder with a specific surface area of 420 kg / m 3 After the powder is placed in an acid solution with a pH value of 2 at a solid-liquid mass ratio of 1:10, it is soaked at room temperature for 140 days, and then the mixture is subjected to solid-liquid separation, and the separated solid is washed with water.

[0074] The preparation method of the calcium silicate board of the embodiment includes the following steps:

[0075] (1) Slurry preparation: the nickel-iron acid leaching residue, calcium raw material, and reinforcing fiber are weighed according to the above proportions, mixed with water to prepare a slurry, and the water content of the slurry is controlled at 30%;

[0076] (2) Green body forming: a flow slurry method is used to prepare a board, and a 300t press is used to press for 2h, so that the water content of the board blank is reduced to 8%;

[0077] (3) Pre-curing: after the board blank is formed, it is demolded after pre-curing at 60°C for 5h;

[0078] (4) Autoclave curing: the pre-cured board blank is placed in an autoclave for autoclave curing, wherein the temperature of the autoclave curing is 130°C, the time of the autoclave curing is 10h, and the steam pressure of the autoclave curing is 1.3MPa;

[0079] (5) Finished product: the autoclave-cured board blank is dried for 3h to obtain the calcium silicate board.

[0080] Example 6

[0081] According to the mass percentage, the raw material addition amount of the calcium silicate board of the embodiment is: nickel-iron acid leaching residue 50%, lime 20%, carbide slag 30%, and magnesite fiber addition amount is 6% of the nickel-iron acid leaching residue and calcium raw material;

[0082] The nickel-iron acid leaching residue is pretreated by the following process: the nickel-iron residue is ground into a powder with a specific surface area of 350 kg / m 3 After the powder is placed in an acid solution with a pH value of 3 at a solid-liquid mass ratio of 1:10, it is soaked at room temperature for 180 days, and then the mixture is subjected to solid-liquid separation, and the separated solid is washed with water.

[0083] The preparation method of the calcium silicate board of the embodiment includes the following steps:

[0084] (1) Slurry preparation: the nickel-iron acid leaching residue, calcium raw material, and reinforcing fiber are weighed according to the above proportions, mixed with water to prepare a slurry, and the water content of the slurry is controlled at 35%;

[0085] (2) Green body forming: a flow slurry method is used to prepare a board, and a 300t press is used to press for 1.5h, so that the water content of the board blank is reduced to 10%;

[0086] (3) Pre-curing: After the slab is formed, it is pre-cured at 70℃ for 7h before demolding;

[0087] (4) Autoclave curing: The pre-cured slab is placed in an autoclave for autoclave curing, wherein the autoclave curing temperature is 120℃, the autoclave curing time is 10h, and the autoclave curing steam pressure is 1.0MPa;

[0088] (5) Finished product: The autoclave-cured slab is dried for 2h to obtain the calcium silicate board.

[0089] According to the test method in JC / T 564.1-2018 “Fiber-reinforced calcium silicate board Part 1: Asbestos-free calcium silicate board”, the flexural strength and physical properties of the calcium silicate boards prepared in Examples 1-6 were tested, and the specific results are shown in Table 1.

[0090] The test results of the calcium silicate boards prepared in the examples of the present application are shown in Table 1, which meet the standard requirements of JC / T 564.1-2018 “Fiber-reinforced calcium silicate board Part 1: Asbestos-free calcium silicate board”.

[0091] Table 1 Flexural strength and physical properties of calcium silicate boards prepared in examples

[0092]

[0093] The above examples are merely examples for clarity and do not limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. It is not necessary or possible to exhaust all embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A calcium silicate board of nickel-iron acid leaching residue, characterized by, The calcium silicate board comprises a nickel ferrite leaching residue, a calcareous raw material, and a reinforcing fiber; and according to the total mass of the nickel ferrite leaching residue and the calcareous raw material being 100%, the mass of the nickel ferrite leaching residue accounts for 50-80%, and the mass of the calcareous raw material accounts for 20-50%. The nickel-iron acid leaching residue is obtained by pretreating the nickel-iron residue through soaking in an acid solution and solid-liquid separation; the process of the pretreatment is as follows: after the nickel-iron residue is ground into a powder with a specific surface area of 350-420 kg / m 3 , the powder is placed in an acid solution with a pH value of 2-3 at a solid-liquid mass ratio of 1:10, and soaked at room temperature for 28-180 days, then the mixture is subjected to solid-liquid separation, and the separated solid is washed with water to obtain the nickel-iron acid leaching residue.

2. The calcium silicate board according to claim 1, characterized in that, The calcareous raw material is one or more of lime, phosphogypsum, and carbide slag, and the effective CaO content is not less than 85%, and the fineness is greater than 250 mesh.

3. The calcium silicate board according to claim 2, characterized in that, The reinforcing fiber is one or more of glass fiber, cellulose, and periclase fiber, and the addition amount is 5-8% of the total mass of the nickel ferrite leaching residue and the calcareous raw material.

4. A method of producing a calcium silicate board from the nickel-iron acid leaching residue according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: (1) pulp preparation: weighing the nickel ferrite leaching residue, the calcareous raw material, and the reinforcing fiber, and mixing them with water to prepare a slurry; (2) green body forming: using the flow slurry method to prepare a plate from the slurry, and using a press to pressurize to obtain a formed plate blank; (3) pre-curing: demolding after pre-curing the formed plate blank; (4) autoclave curing: placing the pre-cured plate blank in an autoclave for autoclave curing; (5) finished product: drying the autoclave-cured plate blank to obtain the calcium silicate board.

5. The preparation method according to claim 4, characterized in that, In step (1), the water content of the slurry is controlled to be 30-40%.

6. The method of claim 5 wherein the step of forming the first and second layers comprises the step of: In step (2), a 300t press is used to pressurize for 1-2h, so that the water content of the plate blank is reduced to 5-10%. ​ 7. The method of claim 6 wherein the step of forming the first and second layers comprises the step of: In step (3), the plate blank is demolded after pre-curing at 30-80℃ for 3-7h. ​ 8. The method of claim 7, wherein the step of applying the coating is performed after the step of applying the first layer of material. In step (4), the autoclave curing temperature is 120-150℃, the steam pressure is 0.8-1.5MPa, and the autoclave curing time is 8-15h.

9. The preparation method according to claim 8, characterized in that, In step (5), drying is performed for 2-4h.

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