GB/T 2275-2017 Magnesia brick and magnesia aluminum brick

Magnesia bricks and magnesia-alumina bricks

1. Scope

This standard specifies the terminology and definitions, classification, shape and size, technical requirements, test methods, quality evaluation procedures, packaging, marking, transportation, storage and quality certificates of magnesia bricks, magnesia-alumina bricks and magnesia-alumina spinel bricks.

This standard is applicable to magnesia bricks, magnesia-alumina bricks and magnesia-alumina spinel bricks used in industrial furnaces in the steel, non-ferrous metals and building materials industries.

2. Normative references

The following documents are indispensable for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest version (including all amendments) applies to this document.

GB/T 2992.1 Refractory bricks - Shape and dimensions - Part 1: General bricks.

GB/T 2997 Test methods for bulk density, apparent porosity and true porosity of dense shaped refractory products.

GB/T 5069 Chemical analysis methods for magnesia-alumina refractories.

GB/T 5072 Refractory materials - Test method for compressive strength at room temperature.

GB/T 5988 Refractory materials - Test method for permanent linear change after heating.

GB/T 7321 Preparation of test samples for shaped refractory products.

GB/T 10325 Acceptance sampling inspection rules for shaped refractory products.

GB/T 10326 Inspection methods for dimensions, appearance and section of shaped refractory products.

GB/T 16546 Packaging, marking, transportation and storage of shaped refractory products.

GB/T 21114 Refractory materials - X-ray fluorescence spectrometry chemical analysis - Molten glass disc method.

GB/T 30873-2014 Refractory materials - Test method for thermal shock resistance.

YB/T 370 Refractory materials - Test method for load softening temperature (non-differential-heating method).

3. Terms and definitions

Defined in GB/T 10325 and the following terms and definitions apply to this document.

3.1 Magnesia brick

Alkaline refractory product mainly composed of periclase, made from magnesia as the main raw material and fired at high temperature.

3.2 Magnesia-alumina brick

Alkaline refractory product mainly composed of periclase as the main mineral phase and magnesia-alumina spinel as the binding phase, made from magnesia and corundum or alumina as the main raw materials and fired at high temperature.

3.3 Magnesia-alumina spinel brick

Alkaline refractory product mainly composed of periclase and magnesia-alumina spinel, made from magnesia and spinel as the main raw materials and fired at high temperature.

4. Classification and dimensions

According to the mineral composition, it is divided into magnesia bricks, magnesia-alumina bricks and magnesia-alumina spinel bricks. According to the physicochemical indexes, magnesia bricks are divided into 7 grades, magnesia-alumina bricks are divided into 1 grade, and magnesia-alumina spinel bricks are divided into 4 grades. See Table 1 for details. In the grade, M, LJ are the initials of magnesium, aluminum and spinel in Chinese Pinyin respectively, and the following Arabic numerals and letters represent the mass fraction of magnesium oxide and the product level respectively.

Table 1 Classification and grades of magnesia bricks, magnesia-alumina bricks and magnesia-alumina spinel bricks

4.2 The shape and dimensions of the bricks shall conform to GB/T 2992.1, and can also be customized according to user requirements.

5. Technical requirements

5.1 The physicochemical indexes of magnesia bricks shall conform to the provisions in Table 2.

Table 2 Physicochemical indexes of magnesia bricks

The physicochemical indicators of 5.2 magnesia-alumina bricks and magnesia-alumina spinel bricks shall conform to the provisions of Table 3.

5.3 Single weight _≥ 35 kg or the technical requirements of bricks with thickness > 100 mm and other special requirements can be negotiated by both the supplier and the demander.

Table 3 Physicochemical indicators of magnesia bricks and magnesia-alumina spinel bricks

5.4 The dimensional deviation and appearance of magnesia bricks, magnesia-alumina bricks and magnesia-alumina spinel bricks shall conform to the provisions of Table 4.

Table 4 Dimensional tolerances and appearance of magnesia bricks, magnesia-alumina bricks and magnesia-alumina spinel bricks Unit: millimeter

6. Test methods

6.1 The inspection and sampling of bricks shall be carried out according to GB/T 7321.

6.2 The determination of chemical composition shall be carried out according to GB/T 5069 or GB/T 21114.

6.3 The determination of apparent porosity and bulk density shall be carried out according to GB/T 2997.

6.4 The determination of compressive strength at room temperature shall be carried out according to GB/T 5072.

6.5 The determination of the load softening start temperature shall be carried out according to YBT 370.

6.6 The determination of the change in permanent linear change after heating shall be carried out according to GB/T 5988.

6.7 The determination of thermal shock resistance shall be carried out according to GB/T 30873-2014 Method 1 and Method 2.

6.8 The inspection of the size and appearance of bricks shall be carried out according to GB/T 10326.

7 Quality assessment procedures

7.1 Batching

Products are batched according to the same grade, and each batch is no more than 120 t.

7.2 Sampling and acceptance criteria

The sampling and acceptance of bricks shall be carried out according to GB/T 10325. Chemical composition, apparent porosity, compressive strength at room temperature, and load softening start temperature are the factory inspection and acceptance items: when the change in permanent linear change after heating is used as an acceptance index, its determination form is: a single value is within the maximum and minimum values, all are judged as qualified.

7.3 Qualification assessment form

Qualification assessment can be carried out in the form of supplier declaration, user identification or third-party certification.

8. Packaging, marking, transportation, storage and quality certificate

8.1 The packaging, marking, transportation and storage of bricks shall be carried out according to GB/T 16546.

8.2 When the bricks are issued, a quality certificate signed by the supplier's quality department shall be attached. The quality certificate shall state the supplier's name or factory mark, the purchaser's name, the production date, the contract number, the product name, the standard number, the grade, the brick number, the batch number and the corresponding physicochemical test results, etc.

Magnesia brick and magnesia aluminum brick

1 Scope

This standard specifies the terms and definitions, classification, shape and size, technical requirements, test methods, quality assessment procedures, packaging, marking, transportation, storage and quality certificates of magnesia bricks, magnesia aluminum bricks and magnesia aluminum spinel bricks.

This standard applies to magnesia brick, magnesia retaining brick and magnesia cuspate brick for industrial furnaces used in iron and steel, non-ferrous metal, and building materials industries.

2 Normative reference documents

The following documents are essential for the application of this document. For dated references, the date-only version applies to all undated references in this document. The latest version (including all change orders) applies to this document.

GB/T 2992.1 Shape and dimensions of refractory bricks – Part 1: general purpose bricks.

GB/T 2997 Test method for bulk density, apparent porosity and true porosity of compact shaped refractory products.

GB/T 5069 Method for chemical analysis of MG-Al refractories.

GB/T 5072 Refractories – normal temperature compressive strength test method.

GB/T 5988 Refractory heating permanent line change test method.

GB/T 7321 Shaped refractory product sample preparation method.

GB/T 10325 Shaped refractory products acceptance sampling inspection rules.

GB/T 10326 Shaped refractory products size, appearance and section inspection method.

GB/T 16546 Shaped refractory products packaging, marking, transportation and storage.

GB/T 21114 Refractories, X-ray fluorescence spectrochemical analysis of fused cast glass sheet method.

GB/T 30873 2014 Test method for thermal shock resistance of refractory materials.

YB/T 370 Test method for load softening temperature of refractories (non-differential warming method).

3. Terms and definitions

The terms and definitions defined in GB/T 10325 and the following terms and definitions apply to this document.

3.1 Magnesia brick

3.2 Magnesia alumina brick

Magnesia is the main raw material. Alkaline refractory products made by high-temperature firing with magnesite as the main mineral composition.

Magnesia and corundum or aluminum clay as the main raw materials, prepared at high temperature with magnesite as the main mineral phase, magnesia-aluminum cuspate as the binding phase of alkaline refractory products.

3.3 Magnesia alumina spinel brick

Magnesia and cuspite as the main raw materials, fired at high temperature made of magnesia and magnesia alumina cuspite as the main mineral composition of refractory products.

4. Classification, shape and size

4.1 According to mineral composition, magnesia brick, magnesia aluminum brick and magnesia aluminum spinel brick are divided into 7 grades according to physical and chemical indexes, magnesia brick is divided into 1 grade, and magnesia aluminum spinel brick into 4 grades. See Table 1 for details. In the brand, M and LJ are the initial letters of magnesium, aluminum and sharp Chinese pinyin respectively, followed by Arabic numerals and letters representing the quality fraction and product grade of magnesium oxide respectively.

Table 1 Classification and grade of magnesia brick, magnesia alumina brick and magnesia alumina spinel brick

4.2 The shape and size of the brick shall comply with GB/T 2992.1, or according to the user’s requirements.

5. Technical requirements

5.1 Physical and chemical indexes of magnesium brick shall conform to the provisions of Table 2.

Table 2 Physical and chemical indexes of magnesian brick

5.2 The physical and chemical indexes of MG-Al bricks and MG-Al spinel bricks shall comply with the provisions of Table 3.

5.3 Technical requirements and other special requirements of bricks with a single weight _≥ 35 kg or thickness >100 mm can be negotiated by both parties.

Table 3 Physical and chemical indexes of MG-Al bricks and MG-Al spinel bricks

5.4 The size deviation and appearance of magnesia brick, magnesia aluminum brick and magnesia aluminum spinel brick shall comply with the provisions of Table 4.

Table 4 The allowable size deviation and appearance of magnesia-aluminum bricks and magnesia-aluminum spinel bricks are measured in millimeters

6. Test methods

6.1 Bricks shall be inspected and prepared according to GB/T 7321.

6.2 Chemical composition shall be determined according to GB/T 5069 or GB/T 21114.

6.3 The apparent porosity and bulk density were measured according to GB/T 2997.

6.4 The compressive strength at room temperature shall be measured according to GB/T 5072.

6.5 The initial temperature of load softening was determined according to YBT 370.

6.6 The determination of permanent line change of heating was carried out according to GB/T 5988.

6.7 The thermal shock resistance was measured according to GB/T 30873-2014 methods 1 and 2.

6.8 The size and appearance of bricks shall be checked according to GB/T 10326.

7 Quality assessment procedures.

7.1 Batch

The products are batched according to the same grade, and each batch is not more than 120 t.

7.2 Rules for sampling and conformity determination

Sampling and acceptance of bricks was carried out in accordance with GB/T 10325. Chemical composition, apparent porosity, normal temperature compressive strength, load softening starting temperature are factory inspection and acceptance items: when the change of heating permanent line is used as acceptance index. Its determination form is: the single value is within the range of maximum and minimum values. All were judged qualified.

7.3 Form of conformity assessment

The conformity assessment can be made in the form of the supplier’s declaration, the user’s certification or the third party’s certification

8. Packing, marking, transportation, storage and quality certificate

8.1 The packaging, marking, transportation and storage of bricks shall be carried out in accordance with GB/T 16546.

8.2 When the bricks are issued, the quality certificate issued by the quality department of the supplier shall be attached. The quality certificate shall state the name of the supplier or factory mark, the name of the demander, the date of production, the contract number, the product name, the standard number, the brand number, the brick number, the lot number and the corresponding physical and chemical inspection results.