Method for preparing refractory castable from calcium-magnesium phosphorite tailings

Abstract

The invention discloses a method for preparing a refractory castable from calcium-magnesium phosphate tailings, and aims to provide a preparation method of a phosphate tailing-based refractory castable with high hydration resistance. The refractory material is formed by mixing a refractory material and a binding agent according to the mass ratio of 100: (2-6). Wherein the refractory material is formed by mixing a calcium-magnesium particle material A and fused magnesia according to a certain proportion. The refractory castable disclosed by the invention has the advantages of high refractoriness, small linear expansion rate, high compressive strength and the like, is an indefinite refractory material with a wide application prospect, can provide a thought for high value-added utilization of the phosphate tailings, and provides support and guarantee for green and healthy development of the phosphorus chemical industry.

Description

Technical Field

[0001] The present invention relates to a method for preparing refractory castables by utilizing calcium-magnesium phosphate tailings, which is a new way to utilize the tailings of phosphate ore beneficiation solid waste from the phosphorus chemical industry. Amorphous refractory materials are known as the second generation of refractory materials and are the key development direction of refractory materials. They are the most promising amorphous refractory materials for refractory castables. Phosphate ore beneficiation tailings contain rich calcium and magnesium elements, and phosphorus can play a role in retarding setting and resisting hydration, which is of great significance for the development of magnesium-calcium castables containing f-CaO and thus promoting the development of the clean steel industry. Background Art

[0002] Phosphate tailings are solid waste generated during the beneficiation stage of phosphorus chemical production. The usual treatment method is to build a warehouse for storage. The storage of phosphate tailings not only poses potential geological environmental risks such as dam breach and dust, but also causes waste of resources and brings huge financial and land pressure to enterprises. Therefore, it is urgent to develop comprehensive utilization technology for phosphate tailings.

[0003] Calcium-magnesium castables are amorphous refractory materials with broad application prospects. Their easy hydration and short setting time are the most critical issues that limit their application. The present invention is based on the "a kind of calcium-magnesium refractory particles with high hydration resistance based on phosphate tailings" (patent application number 202311707836.0) proposed by the applicant, and utilizes the material properties of phosphate tailings to exert its retarding and hydration resistance effects. The calcium particles are applied to the preparation of calcium-magnesium refractory castables, which can not only solve the application problems of calcium-magnesium castables, but also promote the comprehensive utilization of phosphate tailings and realize the green and sustainable development of phosphorus chemical enterprises. Summary of the invention

[0004] In order to solve the problems of easy hydration and short initial setting time in the existing preparation technology of calcium-magnesium castables, the material properties of phosphate tailings are fully utilized to achieve good performance of calcium-magnesium castables without adding modifiers such as zirconium oxide and titanium oxide.

[0005] To achieve the above object, the present invention adopts the following technical scheme: the refractory material and the binder are mixed in a mass ratio of 100: (2-6); The refractory material is calculated by mass percentage and is composed of 40% to 60% of calcium magnesium granule A material and 40% to 60% of high-quality magnesia sand; In calcium magnesium granule A material, 3-5mm accounts for 30%-50%, 1-3mm accounts for 30%-50%, and 0-1mm accounts for 0%-20%; Among high-quality magnesia, 1-3mm accounts for 30%-40%, 0-1mm accounts for 20%-30%, and ≤0.088mm accounts for 30%-50%; The magnesia is fused magnesia.

[0006] The binder is one of calcium aluminate / barium aluminate cement, silica fume, polyaluminium chloride and water glass, and the addition amount is 3% to 6%; after the prepared mixture is fully mixed in a mixer, it is fully stirred at a water-cement ratio of 0.2 to 0.4 to obtain a mixture, which is a refractory castable.

[0007] Due to the adoption of the above technical solution, the present invention has the following positive effects compared with the prior art: ① Using phosphorus tailings as raw materials to prepare calcium-magnesium refractory castables does not require the addition of additional modifiers such as zirconium oxide, titanium oxide, and yttrium oxide, and it itself has good anti-hydration properties.

[0008] ② The calcium-magnesium refractory castable prepared with phosphate tailings as raw materials uses the retarding effect of the phosphate mineral itself to improve construction conditions and solve the problem of too fast hardening speed during the construction of the castable.

[0009] ③ The preparation of calcium-magnesium refractory castables using phosphate tailings as raw materials has broadened the development and utilization of solid waste from the phosphorus chemical industry and can contribute to the green and sustainable development of the phosphorus chemical industry. DETAILED DESCRIPTION

[0010] Several embodiments are listed below to further illustrate the present invention, but are not intended to limit the present invention.

[0011] The following experiment was conducted using Example 1 of a phosphate tailings-based highly hydration-resistant calcium magnesium refractory particle with patent application number 202311707836.0 as a case.

[0012] Example 1 (1) Calcium magnesium granules A: 3-5 mm accounts for 40%, 1-3 mm accounts for 40%, and 0-1 mm accounts for 20% of calcium magnesium granules A; (2) High-quality magnesia: 1-3 mm accounts for 30%, 0-1 mm accounts for 20%, and ≤0.088 mm accounts for 50%; (3) Thoroughly mix 4 kg of calcium magnesium granules A, 6 kg of high-quality magnesia sand, and 0.4 kg of calcium aluminate cement.

[0013] (4) Add water and stir to obtain a mixture with a water-cement ratio of 0.2, vibrate and mold into a test piece of 160×40×40 mm, oxidize at room temperature for 24 hours, then demold and dry, and sinter at 1550°C. Test the apparent porosity, bulk density, flexural and compressive strength, and other indicators.

[0014] The samples in this group have an apparent porosity of 9.8% and a bulk density of 2.73 g / cm 3 , compressive strength 98.3MPa, flexural strength 8.3MPa, linear change rate -2.1%.

[0015] Example 2 (1) Calcium magnesium granules A: 3-5 mm granules account for 50%, 1-3 mm granules account for 50%, and 0-1 mm granules account for 0%; (2) High-quality magnesia: 1-3mm accounts for 30%, 0-1mm accounts for 30%, ≤0.088mm accounts for 40%; (3) Stir and mix 3 kg of calcium magnesium granules A, 7 kg of high-quality magnesia sand and 0.4 kg of silica fume thoroughly.

[0016] (4) Add water and stir to obtain a mixture with a water-cement ratio of 0.23, vibrate and mold into a test piece of 160×40×40 mm, oxidize at room temperature for 24 hours, then demold and dry, and sinter at 1550°C. Test the apparent porosity, bulk density, flexural and compressive strength, and other indicators.

[0017] The samples in this group have an apparent porosity of 20% and a bulk density of 2.82 g / cm 3 , compressive strength 42.1MPa, flexural strength 11.4MPa, linear change rate -0.7%.

[0018] Example 3 (1) Calcium magnesium granules A: 3-5 mm accounts for 50%, 1-3 mm accounts for 40%, and 0-1 mm accounts for 10% of calcium magnesium granules A; (2) High-quality magnesia: 1-3 mm accounts for 40%, 0-1 mm accounts for 30%, and ≤0.088 mm accounts for 30%; (3) Thoroughly stir and mix 5 kg of calcium magnesium granules A, 5 kg of high-quality magnesia sand, and 0.5 kg of polyaluminium chloride.

[0019] (4) Add water and stir to obtain a mixture with a water-cement ratio of 0.18, vibrate and mold into a test piece of 160×40×40 mm, oxidize at room temperature for 24 hours, then demold and dry, and sinter at 1550°C. Test the apparent porosity, bulk density, flexural and compressive strength, and other indicators.

[0020] The samples in this group have an apparent porosity of 18.9% and a bulk density of 2.53 g / cm 3 , compressive strength 38.9MPa, flexural strength 9.5MPa.

[0021] In the above embodiments, the ratio of calcium magnesium granule A material and high-quality magnesia sand raw material can be appropriately adjusted according to actual needs, and the materials of each particle size can also be appropriately changed according to actual construction needs.

Claims

1. A method for preparing refractory castables using calcium magnesium phosphate tailings, characterized in that: It mainly includes the following steps: (1) It is made of refractory material and binder in a mass ratio of 100: (2-6); (2) The refractory material is a mixture of 40% to 60% of calcium magnesium particles A and 40% to 60% of magnesia sand calculated by mass percentage; (3) According to the mass percentage, the calcium and magnesium particles A have a 3-5 mm particle size of 30%-50%, a 1-3 mm particle size of 30%-50%, and a 0-1 mm particle size of 0%-20%; (4) According to the mass percentage, the proportion of 1-3 mm in the magnesia is 30%-40%, the proportion of 0-1 mm is 20%-30%, and the proportion of ≤0.088 mm is 30%-50%; (6) After the prepared mixture is fully mixed in a mixer, it is stirred thoroughly according to a water-cement ratio of 0.2 to 0.4 to obtain a mixture that is a refractory castable.

2. The method for preparing refractory castables using calcium magnesium phosphate tailings according to claim 1, characterized in that: The calcium magnesium particle A material is a phosphate tailings-based calcium magnesium refractory particle with high hydration resistance, which is prepared in application number 202311707836.

0.

3. The method for preparing refractory castables using calcium magnesium phosphate tailings according to claim 1, characterized in that: The aggregate accounts for 65% to 80% of the refractory material, and the powder accounts for 20% to 35%; the aggregate is a material with a particle size of 0 to 5 mm; the powder is a material with a particle size of less than 0.088 mm.

4. The method for preparing refractory castables using calcium magnesium phosphate tailings according to claim 1, characterized in that: The binder is one of calcium aluminate / barium aluminate cement, silica fume, polyaluminium chloride and water glass; the amount of the binder is 3%-6% of the total amount of the refractory material.