Inorganic fiber modifier and application thereof in preparation of high-strength corrosion-resistant inorganic fiber

Abstract

The invention discloses an inorganic fiber modifier and application thereof in preparation of high-strength corrosion-resistant inorganic fibers, and belongs to the technical field of surface modification of inorganic fiber materials. The modifier is prepared from the following components in percentage by mass: 25 to 35 percent of silane coupling agent, 20 to 28 percent of SiO2 / Al2O3 nano sol, 18 to 22 percent of zinc phosphate, 6 to 8 percent of benzotriazole derivative, 4 to 6 percent of ammonium polycarboxylate and the balance of deionized water. Performance breakthroughs are achieved through a slag ball gradient removal-structure strengthening-chemical bonding triple synergistic process: 1, multi-stage air flotation separation (8-5 m / s) is combined with micro-acid etching (5% H2SO4 + 0.5% HF), and the slag ball residual quantity is smaller than 3 vol%; 2, a Si-O-M bonding network (XPS bonding energy is 102.3 eV) is constructed through a step curing process, and the tensile strength reaches 520-580 MPa; and 3, the penetration depth of the nano sol is more than 200nm through ultrasonic-assisted dipping, and the weight loss rate of the nano sol resistant to 5% HCl corrosion is reduced to 0.38%. The invention solves the technical problems of high defect rate and poor corrosion resistance of industrial solid waste fiber slag balls, and is suitable for resource utilization of bulk industrial solid wastes such as fly ash, slag and the like and hazardous wastes such as surface treatment wastes, sludge, distillation residues and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface modification of inorganic fiber materials, and specifically relates to an inorganic fiber modifier prepared based on high-temperature melting of industrial solid waste (including fly ash, coal gangue, surface treatment waste, sludge and other wastes) and its gradient solidification process, which is particularly suitable for improving the mechanical strength and chemical medium tolerance of the fiber. Background Art

[0002] Industrial solid waste, including fly ash, coal gangue, slag and other bulk industrial solid wastes, as well as surface treatment waste, sludge, distillation residue and other hazardous wastes, are extracted by high-temperature melting to extract valuable metals, and then the inorganic fibers are prepared by centrifugal spinning and modification. There are the following technical bottlenecks:

[0003] 1. Slag ball defects: fluctuations in raw material composition lead to slag ball (particle size > 50μm unmelted particles) production > 8wt%, fiber breaking strength < 300MPa;

[0004] 2. Surface microcracks: SEM observation crack density > 15 / μm 2 , 5% HCl solution corrosion weight loss rate> 2.5% / 24h;

[0005] 3. Defects of existing modification technology:

[0006] o The physical screening method is inefficient: For example, CN108442105A uses a combination of vibration screening and defoaming agent, which reduces bubbles but only removes 60-75% of the slag balls, and does not solve the fiber component defects;

[0007] o The step-by-step treatment process is complex: For example, CN110592945B uses a dispersant and a softener for step-by-step treatment. Although it improves the dispersibility, it does not form a chemical bonding network and is prone to failure in a hot and humid environment.

[0008] Chinese patent (CN108442105A) discloses an inorganic fiber composite modifier, which includes dodecylamine, sodium chloroacetate, sodium hydroxide and defoamer, and improves fiber flexibility by inhibiting bubble generation. However, it has the following defects:

[0009] 1. Insufficient slag ball removal: The slag ball removal process is not integrated, and the residual slag ball in the finished product is > 8wt%;

[0010] 2. Poor corrosion resistance: A single organic component (such as dodecylamine) cannot form a stable bond with metal oxides, and the weight loss rate after immersion in 5% HCl solution for 24 hours is greater than 1.8%;

[0011] 3. Low wet and hot stability: The modified layer is mainly based on physical adsorption, and the coating falls off after 72 hours in an environment of 85℃ / RH95%. The Chinese patent (CN110592945B) proposes a step-by-step treatment process, first using dispersant A to pre-disperse the fiber, and then using softener B for modification. Its technical limitations are:

[0012] 1. Complicated process: requires step-by-step operation, increasing production costs;

[0013] 2. Low bonding strength: No chemical bonding network is constructed, and the XPS detection bonding energy is only 98.7eV (physical adsorption);

[0014] 3. Insufficient acid resistance: The weight loss rate of modified fiber in 5% HCl solution is >1.5% / 24h.

[0015] Existing treatment technologies have a series of common defects, including single function limitations. Neither physical screening nor chemical modification can take into account both slag ball removal and structural strengthening; insufficient corrosion resistance, and the modified layer is easily corroded by acid and alkali media; poor process adaptability and unstable performance when the hazardous waste composition fluctuates. Summary of the invention

[0016] Purpose of the Invention

[0017] In view of the above defects, the present invention develops a composite modification system with the triple functions of "slag ball gradient removal - structural strengthening - chemical bonding" to achieve:

[0018] 1. The fiber body defect rate is reduced and the surface densification is synergistically enhanced;

[0019] 2. The corrosion-resistant component forms a chemical bonding network with the fiber matrix;

[0020] 3. The process adapts to the fluctuations in the composition of industrial solid waste.

[0021] Core formula optimization

[0022] The modifier contains the following components in percentage by weight:

[0023]

[0024]

[0025] Process innovation

[0026] 1. Slag ball gradient removal:

[0027] oMulti-stage flotation separation (8→5m / s velocity gradient), slag ball residue <3vol%;

[0028] o Slightly acid etched (5% H 2 SO 4+0.5% HF, 60±2℃) selectively dissolves Fe 2 O 3 Impurities;

[0029] 2. Ultrasonic assisted impregnation:

[0030] o 40-60kHz ultrasonic field promotes the penetration of nanoparticles into the submicron pores of the fiber (TEM shows penetration depth > 200nm);

[0031] 3. Step curing process:

[0032] o 80-100℃ / 30min initial polycondensation → 140-160℃ / 1h complete Si-O-Al bond formation (XPS detection bonding energy 102.3eV);

[0033] oThe final curing stage is carried out under nitrogen protection.

[0034] Technical Effects

[0035]

[0036] Innovative Description

[0037] The present invention breaks through the limitations of existing technologies through "ternary bonding network + gradient process":

[0038] 1. The residual amount of slag balls is reduced by 75% compared with CN108442105A;

[0039] 2. Si-OM bonding energy (102.3 eV) is 18.6% higher than that of CN110592945B physical adsorption;

[0040] 3. Acid resistance is 7 times higher than that of traditional processes, adapting to fluctuations in industrial solid waste composition. DETAILED DESCRIPTION

[0041] Embodiment 1 (best practice)

[0042] 1. Take 100kg of industrial solid waste molten fiber, and after three-stage air flotation separation (8→6→5m / s), the slag ball content is 2.8vol%;

[0043] 2. Prepare modifier: KH-550 silane 32%, SiO 2 / Al 2 O 3 Composite sol 25%, zinc phosphate 20%, methyl benzotriazole 7%, ammonium polycarboxylate 5%, water 11%;

[0044] After 3.60Hz ultrasonic impregnation, two-step curing was performed under nitrogen protection to obtain:

[0045] oTensile strength 572MPa (ISO 3342 standard);

[0046] o 5% H 2 SO 4 The weight loss rate after immersion for 30 days is 0.41%.

[0047] Example 2 (Comparison of process parameters)

[0048] ●Comparative Example 1: Omitting the silane coupling agent, the tensile strength dropped to 320MPa, and the weight loss rate increased to 2.5%;

[0049] ●Comparative Example 2: Using single-stage flotation separation (8m / s), the residual amount of slag balls increased to 7.2vol%.

[0050] ●Comparative Example 3: Testing the impact of curing process under fixed formula conditions:

[0051]

Claims

1. A hazardous waste-based inorganic fiber modifier, characterized in that The invention is composed of the following components in percentage by mass: 25-35% of silane coupling agent, 20-28% of nano-sol, 18-22% of phosphate, 6-8% of benzotriazole derivative, 4-6% of polycarboxylate, and the balance is deionized water.

2. as the modifying agent described in right 1, it is characterized in that The phosphate is a compound of zinc phosphate and aluminum phosphate in a ratio of 1:0.5-2.

3. as the modifying agent described in right 1, it is characterized in that The nano-sol particle size is 10-30 nm and is pre-grafted with silane.

4. An inorganic fiber modification process, characterized in that include: a) Air flotation separation: Use multi-stage airflow with a velocity gradient of 8-5m / s to separate the slag balls; b) Acid etching: using a composite acid solution of 5% H2SO4 + 0.5% HF; c) Ultrasonic immersion: treatment in a 40-60kHz ultrasonic field for 15-30 minutes; d) Step curing: pre-curing at 80-100℃ and final curing at 140-160℃.

5. The process as claimed in claim 4, characterized in that The final curing stage was carried out under nitrogen protection.

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