Foreword
According to the requirements of the Notice on Printing and Distributing the 2017 Formulation and Revision of Engineering Construction Standard Specifications and Related Work Plan (JB [20163248]) issued by the Ministry of Housing and Urban Rural Development, the standard preparation team, after extensive investigation and research, conscientiously summarized practical experience, referred to relevant international standards and advanced international standards, and based on extensive consultation, formulated this standard.
The main technical contents of this standard are: general rules, terms and abbreviations, material storage and preparation, roasting molybdenum concentrate smelting process, ferromolybdenum smelting process, ammonium molybdate wet extraction process, pure molybdenum trioxide preparation process, molybdenum powder preparation process, general layout and workshop configuration, and metallurgical calculation.
The clauses marked in bold in this standard are mandatory and must be strictly implemented. The Ministry of Housing and Urban Rural Development is responsible for the management and interpretation of the mandatory provisions of this standard, the China Nonferrous Metals Industry Engineering Construction Standards and Specifications Management Office is responsible for the daily management, and China ENFI Engineering Technology Co., Ltd. is responsible for the interpretation of the specific technical content. If you have any comments or suggestions during the implementation process, please send them to China ENFI Engineering Technology Co., Ltd. (address: No. 12 Fuxing Road, Beijing 100038).
1 General
1.0.1 This standard is formulated to unify the process design standard of molybdenum smelting plant and achieve advanced technology, reasonable economy, safety, reliability, energy conservation and environmental protection.
1.0.2 This standard is applicable to the process design of newly-built, expanded and reconstructed molybdenum smelters.
1.0.3 The process design of molybdenum smelting plant shall meet the following requirements:
1. When the molybdenum smelter is constructed by stages, a comprehensive planning and design shall be made;
2. Smelting process with mature technology and advanced economic indicators shall be adopted;
3 Intelligent machinery and instrument equipment shall be integrated to realize automatic process control and digital management;
4 The product structure shall be reasonably determined
5 The selected new process shall have industrial test data or relevant appraisal report.
1.0.4 Environmental protection, safety, fire protection and occupational health facilities shall be designed, constructed and put into production and use simultaneously with the main works.
1.0.5 The process design of molybdenum smelting plant shall not only comply with this standard, but also comply with the provisions of current national standards.
2 Terms and Abbreviations
2.1 Terminology
2.1.1 Molybdenum concentrate
molybdenum concentrate
Molybdenum concentrate produced by molybdenum ore flotation process.
2.1.2 Roasted molybdenum concentrate
The product after oxidation roasting of molybdenum concentrate.
2.1.3 ferrous molybdenum
Molybdenum containing ferroalloy produced by the method outside the furnace.
2.1.4 ammonium molybdate
The general term of ammonium molybdate salts, such as ammonium dimolybdate, ammonium tetramolybdate and ammonium heptamebdate.
2.1.5 Ammonium Dimolybdate
ammonium dimolybdate
The product generated after evaporation and crystallization of ammonium molybdate solution.
2.1.6 Ammonium tetramolybdate
The product generated after neutralization and crystallization of ammonium molybdate solution.
2.1.7 Ammonium heptamolybdate
The product of high concentration ammonium molybdate solution after cooling and crystallization.
2.1.8 Pure molybdenum trioxide
pure molybdenum trioxide
Hexavalent molybdenum oxide prepared by calcination of ammonium molybdate.
2.1.9 Molybdenum powder
molybdenum powder
Metal powder prepared from pure molybdenum trioxide by hydrogen reduction.
2.1.10 Cleaning charge
Sintered and unqualified block materials.
3 Material storage and preparation
3.1 Raw materials
3.1.1 The quality of molybdenum concentrate shall comply with the relevant provisions of the current industry standard Molybdenum Concentrate YS/T 235.
3.1.2 The quality of roasted molybdenum concentrate shall comply with the relevant provisions of the current national standard Roasted Molybdenum Concentrate GB/T24482.
3.1.3 Molybdenum concentrate storage shall meet the following requirements:
1 It shall be stored in the concentrate silo with enclosure structure.
2 Concentrate unpacking and sampling measures shall be taken; Dust prevention and collection facilities shall be provided; When the composition of concentrate fluctuates greatly, it is advisable to take mixing homogenization measures.
3 Anti freezing facilities should be provided for molybdenum concentrate storage in cold areas.
4 Molybdenum concentrate silo shall be equipped with metering scales and sample dividing facilities, and the accuracy of metering scales shall be less than 0.2%.
3.1.4 The storage time of materials shall meet the following requirements:
1 The storage days shall be determined according to the material characteristics, convenient transportation, distance and raw material procurement
2 The storage time of molybdenum concentrate should not be less than 5d.
3.2 Auxiliary materials
3.2.1 The flux shall meet the following requirements:
1 Ferrosilicon used for ferromolybdenum smelting shall comply with the relevant provisions of the current national standard Ferrosilicon GB/T 2272.
2 The mass ratio of aluminum particles with particle size less than 0.5mm for ferromolybdenum smelting shall not be greater than 10%, and the mass ratio of particles with particle size greater than 3mm shall not be greater than 10%; The mass ratio of active aluminum particles shall not be less than 96%.
4 Smelting process of roasted molybdenum concentrate
4.1 General provisions
4.1.1 Multi chamber furnace or rotary kiln roasting process should be adopted for molybdenum concentrate roasting, instead of reverberatory furnace production process.
4.1.2 The production capacity of roasted molybdenum concentrate of newly-built, expanded or rebuilt enterprises shall not be less than 15000t/a.
4.1.3 Roasted molybdenum concentrate products shall comply with the relevant provisions of the current national standard Roasted Molybdenum Concentrate GB/T24482.
4.2 Multi chamber furnace roasting process
4.2.1 The total moisture content of molybdenum concentrate oil should not be more than 6%, and the particle size of agglomerate should be less than 4mm; When the total content of oil and water is greater than 6%, it should be dried. The drying heat source should be clean energy, and the drying tail gas should be equipped with treatment facilities.
4.2.2 The molybdenum content in molybdenum concentrate should not be less than 49%, the copper content should not be greater than 0.25%, the lead content should not be greater than 0.20%, and the calcium oxide content should not be greater than 1.8%. For molybdenum concentrates of different grades, ore blending and impurity content should be controlled before roasting.
4.2.3 Molybdenum concentrate shall be measured when it is fed into the furnace, and belt weigher or metering screw can be used.
4.2.4 The production capacity of roasted molybdenum concentrate of a single multi chamber furnace shall not be less than 18000t/a, and the production capacity of highly soluble roasted molybdenum concentrate of a single multi chamber furnace shall not be less than 12500t/a.
4.2.5 It is better to adopt 8-16 layer multi hearth furnace for roasting molybdenum concentrate, and the central shaft and trailing arm should adopt air cooling structure. The furnace temperature of each layer can be controlled and adjusted.
4.2.6 Multi chamber furnace shall be equipped with accident safety interlocking device and shall have dual power supply or DC power supply system.
4.2.7 Main control parameters of multi chamber furnace shall meet the following requirements:
1. The annual working days of multi hearth furnace shall be 300d~330d;
5 Ferromolybdenum smelting process
5.1 General provisions
5.1.1 The quality of ferromolybdenum products shall comply with the relevant provisions of the current national standard Ferromolybdenum GB/T 3649.
5.1.2 Ferromolybdenum smelting shall adopt silicon aluminothermic reduction process. 5.1.3 Ferromolybdenum smelting shall adopt fluorine free process.
5.1.4 Smelting capacity of newly-built, expanded or reconstructed ferromolybdenum production line shall not be less than 15000t/a.
5.2 Batching
5.2.1 The raw and auxiliary materials should be batched in silos, and the amount of raw and auxiliary materials should be stored in silos for more than 4h. 5.2.2 Screw conveyor or closed belt conveyor should be used for material transportation, and heavy bucket elevator should be used for vertical material transportation, and its rated transportation volume should be 3 times greater than the designed and calculated transportation volume.
5.2.3 The control system of ferromolybdenum batching equipment shall be set with safety interlock control.
5.2.4 Ferromolybdenum batching shall adopt automatic batching and uniform mixing measures. The mixing ratio shall be set according to the composition of raw and auxiliary materials, and the metering equipment shall be checked regularly.
5.2.5 Aluminum particles should be stored in silos and grounded statically. Aluminum particles should be added without impact and grinding. Fire fighting facilities such as fire blanket and dry sand should be set up.
5.2.6 Dust removal facilities shall be provided for ferromolybdenum batching process.
5.2.7 Sodium nitrate shall be stored separately. The storage capacity of sodium nitrate silo shall not exceed 8h and shall not be affected with damp.
5.3 Smelting
5.3.1 Ferromolybdenum smelting should adopt circular track layout, and smelting hood should adopt fixed hood or mobile hood, instead of lifting hood.
6. Wet extraction process of ammonium molybdate
7. Preparation process of pure molybdenum trioxide
8. Preparation process of molybdenum powder
9 General Layout and Workshop Configuration
10 Metallurgical calculation
Description of words used in this standard
List of reference standards
Foreword
1 General
2 Terms and Abbreviations
3 Material storage and preparation
4 Smelting process of roasted molybdenum concentrate
5 Ferromolybdenum smelting process
6. Wet extraction process of ammonium molybdate
7. Preparation process of pure molybdenum trioxide
8. Preparation process of molybdenum powder
9 General Layout and Workshop Configuration
10 Metallurgical calculation
Description of words used in this standard
List of reference standards
