I. Core Product Features (Focused on Industrial Scenarios, Highlighting the Iron-Free Core Advantage)

1.1 Morphological and Structural Characteristics (Adapted for Industrial Batch Use)

• Neat appearance with intuitively visible purity: The product appears as a white or off-white crystalline powder or granules (particle size can be customized according to industrial working conditions), featuring uniform crystals, no caking, no impurities, no visible black spots or colored particles, and consistent color. Different from the grayish-white or light yellow appearance of ordinary industrial aluminum sulfate, it intuitively demonstrates its iron-free advantage. The product purity can be quickly judged by its appearance, preventing process abnormalities caused by impurities in industrial production.
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• Stable crystalline structure, convenient for industrial storage: It exists as aluminum sulfate hexahydrate or octadecahydrate crystals with a stable molecular structure, resistant to weathering and decomposition. Under conventional industrial storage conditions (dry and ventilated), it hardly absorbs moisture or cakes, ensuring long-term stability of product performance and meeting the requirements of large-scale industrial storage and long-term turnover.
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• Excellent water solubility, suitable for rapid industrial operations: It is readily soluble in water but insoluble in organic solvents such as ethanol and acetone. At room temperature (20°C), its solubility can reach 36g per 100mL of water, with a fast dissolution rate. After dissolution, it forms a clear and transparent aqueous solution without precipitation or turbidity, requiring no prolonged stirring. It is adaptable to scenarios involving continuous on-site industrial operations and rapid dosing, such as wastewater treatment workshops and paper production lines.
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1.2 Core Performance Characteristics (Tailored to Industrial Production Requirements)

• Extremely low iron content, eliminating secondary industrial pollution: Its core advantage lies in an iron content of ≤0.005% (high-purity industrial grade with ≤0.003% iron content is available for customization), which is far lower than that of ordinary industrial aluminum sulfate (iron content ≥0.5%). During industrial applications, iron impurity oxidation will not cause discoloration of aqueous solutions or yellowing of products, avoiding contamination of industrial raw materials, finished products and treatment media (such as printing and dyeing fabrics, paper pulp, and industrial wastewater effluent). Meanwhile, it reduces corrosion of industrial equipment and pipelines caused by iron impurities, lowering equipment maintenance costs.
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• Outstanding adsorption and flocculation performance, improving industrial treatment efficiency: The aqueous solution is acidic and hydrolyzes to form aluminum hydroxide colloid, which has extremely strong adsorption capacity. It can rapidly adsorb impurities such as suspended solids, colloidal particles, organic matter, and heavy metal ions in industrial wastewater, forming dense and large flocs with a fast sedimentation rate (≥18mm/min, tested with tap water). Its flocculation effect is superior to that of ordinary aluminum sulfate, with lower dosage. It can significantly enhance the efficiency of industrial wastewater treatment and water purification, and reduce the cost of industrial chemical consumption.
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• Strong stability and adaptability to complex industrial working conditions: It maintains stable performance and is not easily decomposed within a temperature range of 5-60℃ and a pH range of 2-8. It can adapt to various types of industrial wastewater (such as high-turbidity wastewater, acidic wastewater, and heavy metal-containing wastewater) as well as different production processes. It does not undergo antagonistic reactions with common industrial inorganic and organic chemicals, featuring strong compatibility. It can be used synergistically with other flocculants and coagulant aids to further enhance treatment effects, making it suitable for complex industrial operating conditions.
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• Non-toxic and environmentally friendly, complying with industrial environmental protection standards: The product itself is non-toxic and non-irritating, leaving no harmful residues after dissolution. Treated industrial wastewater can meet the national industrial wastewater discharge standard (GB 8978-1996). It poses no harm to the environment or human health, satisfies industrial environmental protection acceptance requirements, and helps enterprises achieve green production.
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• Low corrosivity and reduced wear on industrial equipment: Compared with other industrial inorganic flocculants (such as polyaluminum chloride and ferrous sulfate), it has lower corrosivity and causes less damage to industrial equipment and transportation pipelines. It can be directly stored and transported using ordinary carbon steel and plastic equipment without additional anti-corrosion treatment, significantly reducing the equipment maintenance costs for industrial users.

1.3 Industrial Exclusive Adaptation Features

• Suitable for high-volume industrial applications: Available in both granular and powder forms. The granular form is convenient for large-scale storage and transportation, making it ideal for bulk use by large industrial enterprises (such as water plants, large paper mills, and chemical industrial parks); the powder form dissolves quickly, suitable for small-batch rapid operations in small industrial workshops and laboratories.
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• Suitable for industry-sensitive processes: In industrial scenarios such as paper sizing and printing and dyeing fixation, its iron-free property can prevent product discoloration and uneven color, ensure stable quality of finished industrial products, improve the yield rate of finished products, and reduce production losses caused by impurities.
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• Suitable for low-temperature industrial scenarios: It can still maintain good solubility and flocculation effect in low-temperature environments (5-15℃). Compared with ordinary aluminum sulfate, it has stronger adaptability to low temperatures and can be used for industrial wastewater treatment in northern China during winter and low-temperature production processes. No additional heating is required, reducing industrial energy consumption.
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• Suitable for the treatment of complex industrial wastewater: It can treat various types of industrial wastewater such as electroplating wastewater, chemical wastewater, aquaculture wastewater, slaughterhouse wastewater, printing and dyeing wastewater, etc. It can effectively flocculate and remove impurities in wastewater including heavy metal ions (such as lead, cadmium, chromium), suspended solids and organic matters, enabling the wastewater to meet discharge standards or be recycled, thus meeting the requirements of industrial environmental protection governance.

• II. Product Application Classification (Focusing on the Industrial Field, Covering Core Application Scenarios)

  Industrial-grade solid iron-free aluminum sulfate is widely used in core industrial fields such as industrial wastewater treatment, papermaking, printing and dyeing, chemical engineering, and environmental protection due to its high purity, iron-free contamination, excellent flocculation performance, and strong adaptability. It has clear core applications in different industries and precisely meets the needs of industrial production. Its application effects can be intuitively presented with pictures, as detailed below:

  2.1 Industrial Wastewater Treatment Industry (Core Uses: Wastewater Purification, Flocculation and Clarification)

  As a core flocculant for industrial wastewater treatment, it is suitable for the pretreatment and advanced treatment of various types of industrial wastewater. Its key functions include removing impurities such as suspended solids, colloids, organic matter, and heavy metal ions from wastewater, enabling the wastewater to meet discharge standards or be recycled, thereby reducing enterprises' environmental protection pressure. It is the preferred agent for industrial environmental protection and treatment.

  
  

  • Integrated Industrial Wastewater Treatment: Used for the integrated wastewater treatment in chemical industrial parks and industrial parks. After application, it quickly flocculates impurities such as sediment, organic matter, and colloidal particles in water to form flocs for sedimentation. The supernatant, after filtration, meets the requirements of GB 8978-1996 *Integrated Wastewater Discharge Standard*. It causes no iron pollution, avoids secondary pollution of wastewater, and is suitable for the unified treatment of various types of industrial wastewater.
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  • Electroplating Wastewater Treatment: For electroplating wastewater (containing heavy metal ions, cyanide, suspended solids, etc.), heavy metal ions such as lead, cadmium, chromium, and nickel in the wastewater are adsorbed through flocculation to form dense flocs for sedimentation, achieving the separation and removal of heavy metal ions. Meanwhile, suspended solids in the wastewater are removed to ensure the wastewater meets discharge standards and prevent heavy metals from polluting soil and water sources.
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  • Printing and Dyeing Wastewater Treatment: Used for the flocculation treatment of printing and dyeing wastewater, it rapidly adsorbs impurities such as dyes, pigments, suspended solids and organic matters in the wastewater to form flocs for sedimentation. The supernatant can be recycled or discharged up to standard. Iron-free pollution avoids secondary discoloration of the wastewater, reduces environmental protection pressure in the printing and dyeing industry, and lowers water resource consumption.
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  • Treatment of Breeding and Slaughtering Wastewater: For breeding wastewater and slaughtering wastewater (containing a large amount of suspended solids, organic matter, ammonia nitrogen, etc.), efficient flocculation is adopted to remove suspended solids and part of the organic matter in the water, reduce the COD and BOD content of the wastewater, lay a foundation for the subsequent biochemical treatment process, improve wastewater treatment efficiency, and achieve discharge up to standard.
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  • 2.2 Paper Industry (Core Applications: Sizing, Retention and Drainage Assistance)

  
  

  Its iron-free property makes it the preferred chemical for the production of medium-to-high-grade industrial paper, packaging paper, and cultural paper. It prevents paper yellowing, embrittlement, and uneven color caused by iron impurities in ordinary industrial aluminum sulfate, improves paper quality and service life, and meets the large-scale production requirements of the paper industry.

  
  

  • Paper sizing: As the core raw material for acidic sizing agents, it is used synergistically with rosin size and sizing agents to form a protective film on the paper surface. This enhances the water resistance and oil resistance of paper, prevents ink penetration, and avoids discoloration and yellowing of paper caused by iron impurities. It is suitable for the production of industrial-grade cultural paper, printing paper, and packaging paper, improving the qualified rate of finished paper products.
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  • Retention and drainage aid: During the pulp papermaking process, it adsorbs fine fibers and fillers (such as calcium carbonate and talc powder) in the pulp, reduces fiber loss, and improves pulp yield. Meanwhile, it accelerates the pulp filtration rate, enhances papermaking production efficiency, and lowers production costs without affecting the whiteness and color of the paper. It meets the demands for large-scale and high-efficiency production in the papermaking industry.
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  • Paper Dyeing Assistance: Acting as a mordant during the paper dyeing process, it improves the adsorption capacity of dyes, resulting in uniform and bright paper color that is resistant to fading. It is suitable for the production of industrial-grade dyed paper, art paper, and packaging dyed paper, meeting the color requirements of various industrial paper products.
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  2.3 Printing and Dyeing Industry (Core Applications: Color Fixation, Wastewater Treatment, Pretreatment)

  It is suitable for industrial printing and dyeing processes of various fabrics such as cotton, linen, silk, and chemical fibers. Iron-free pollution can avoid problems such as color spots, color stains, and uneven color after fabric dyeing. Meanwhile, it is used in the treatment of printing and dyeing wastewater to achieve environmentally compliant discharge, meeting the demands of large-scale production in the printing and dyeing industry.

  
  

  • Fabric color fixation: As a raw material for cationic fixing agents, it is used in the industrial color fixation treatment of reactive dyes and acid dyes, enhancing the binding force between dyes and fabrics, reducing color fading and staining during the dyeing process, and ensuring long-lasting and bright fabric color. It is especially suitable for the industrial dyeing of light-colored and high-grade fabrics, improving the quality of printed and dyed finished products.
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  • Printing and dyeing wastewater treatment: Used for the flocculation treatment of printing and dyeing wastewater, it rapidly adsorbs impurities such as dyes, pigments, suspended solids and organic matter in the wastewater to form flocs for sedimentation. The supernatant can be recycled or discharged up to standard, reducing the environmental protection pressure of the printing and dyeing industry. Meanwhile, it avoids secondary pollution of wastewater caused by iron impurities, helping enterprises pass environmental protection inspections.
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  • Pre-treatment for printing and dyeing: During the desizing and scouring of fabrics, it is used to remove impurities and sizing agents from the fabric surface, improve the water absorbency and dyeing uniformity of the fabric, lay a foundation for the subsequent dyeing process, reduce dyeing defects caused by incomplete pre-treatment, and enhance the efficiency of printing and dyeing production.
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  2.4 Chemical Industry (Core Applications: Raw Material Synthesis, Catalysts, Wastewater Treatment)

  Its high purity and iron-free properties make it suitable for use as a raw material and catalyst in the chemical industry, as well as for chemical wastewater treatment. It meets the stringent requirements of chemical production, ensures product purity and production safety, and helps chemical enterprises achieve green production.

  
  

  • Chemical raw material synthesis: Used in the production of chemical products such as alum, aluminum salts, and artificial gemstones. Being iron-free ensures the purity and performance of synthesized products, prevents iron impurities from affecting product quality, and meets the demands of large-scale production of chemical raw materials.
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  • Catalyst raw material: Used in the synthesis of organic catalysts and petrochemical catalysts. Its high purity and iron-free characteristics can improve the activity and stability of catalysts, extend their service life, reduce catalyst consumption costs in chemical production, and meet the production needs of the petrochemical and organic chemical industries.
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  • Chemical wastewater treatment: Used for the purification and treatment of chemical wastewater, removing impurities such as organic matter, drug residues, suspended solids, and heavy metal ions from the wastewater to meet discharge standards, avoid environmental pollution, and satisfy the environmental protection and governance needs of chemical enterprises. It is especially suitable for the treatment of fine chemical wastewater with high water quality requirements.
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  2.5 Other Industrial Fields (Core Applications: Environmental Protection and Treatment, Soil Improvement, Flame Retardancy)

  • Environmental protection and treatment assistance: Used in industrial waste gas treatment (such as desulfurization and denitrification) as an auxiliary agent to adsorb harmful components in waste gas, improve the efficiency of waste gas treatment, and adapt to industrial waste gas treatment scenarios. It can also be used for industrial sludge dewatering, helping sludge form compact flocs, improving dewatering efficiency, and reducing sludge discharge.
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  • Soil Improvement: As an industrial-grade soil amendment, it is used to improve acidic soil, adjust soil pH, and enhance soil structure. It is suitable for scenarios such as industrial wastelands and mine reclamation, supporting soil remediation and achieving ecological and environmental protection.
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  • Flame retardant raw material: Used in the fire protection industry and building materials industry as a raw material for flame retardants to enhance the flame retardant effect of products. It is suitable for the production of fire-resistant building materials and fire-fighting equipment, meeting industrial fire safety requirements.

  • III. Product Specifications (Exclusive for Industrial Grade, Customizable to Adapt to Industrial Working Conditions)

    The specifications and parameters of industrial-grade solid iron-free aluminum sulfate are strictly customized according to the requirements of different industrial sectors and application scenarios. Below are the conventional standard specifications for industrial use, covering core parameters such as form, purity, physical and chemical properties, and packaging. The parameter ranges and testing methods are clearly defined to ensure the product is suitable for various industrial applications. All parameters comply with relevant national and industrial standards.

    3.1 Basic Morphological Parameters (Suitable for Industrial Batch Use)

    Product Form	Particle size range	Color	Water of crystallization content	Solubility (20℃)
    Powdery	100-200 mesh (customizable)	White/slightly white, free of impurities	18-water (Al₂(SO₄)₃·18H₂O)	Dissolves completely within ≤20 minutes, resulting in a clear solution.
    Granular	20-80 mesh (customizable)	White/slightly white, free of impurities	18-water / 6-water (customizable)	Completely dissolves within ≤30 minutes, resulting in a clear solution.

    Note: Powdered products dissolve faster and are suitable for small‑dose, rapid‑operation scenarios (e.g., small industrial wastewater treatment equipment, laboratories); granular products are easy to store and transport, making them ideal for large‑scale applications (e.g., chemical industrial parks, large paper mills, water plants). The water of crystallization content can be customized according to the user’s industrial working conditions. The hexahydrate product has low moisture content, is more suitable for storage in dry environments, and meets the storage needs of industrial enterprises in northern China.

    3.2 Core Purity and Performance Parameters (Key Industrial-Grade Indicators, Adaptable to Different Industrial Scenarios)

    Parameter Name	Unit	Standard Value for General Industrial Grade	Standard Value for Industrial High-Purity Grade	Customized Standard Values for Industrial Special Use	Detection Method
    Al₂(SO₄)₃ content	%	≥99.0	≥99.5	≥99.8 (customizable as required)	titration method
    Iron (Fe) content	%	≤0.005	≤0.003	≤0.001 (customizable as required)	spectrophotometry
    Water-insoluble matter content	%	≤0.10	≤0.05	≤0.02 (customizable as required)	gravimetric method
    pH value (1% aqueous solution)	-	2.5-3.5	2.5-3.5	2.0-4.0 (customizable as required)	pH meter detection method
    Chloride (Cl⁻) content	%	≤0.01	≤0.005	≤0.003 (customizable as required)	Silver nitrate titration method
    Heavy metal content (calculated as Pb)	mg/kg	≤10	≤5	≤3 (customizable as required)	Atomic absorption spectrophotometry
    Arsenic (As) content	mg/kg	≤2	≤1	≤0.5 (customizable as required)	Gutzeit method
    flocculation settling velocity	mm/min	≥18 (Industrial wastewater test)	≥20 (Industrial wastewater test)	≥22 (High-turbidity wastewater test)	Sedimentation test method

    Note: 1. Industrial Regular Grade is suitable for conventional industrial scenarios such as ordinary industrial wastewater treatment and paper sizing; Industrial High-Purity Grade is suitable for scenarios including fine chemical engineering, high-grade papermaking, and high-demand wastewater treatment; Industrial Customized Grade can customize parameters such as iron content, particle size, and pH value according to users' specific industrial working conditions.
    2. All parameters comply with industrial industry standards. CMA/CNAS certified test reports are available to meet the environmental protection acceptance and quality audit requirements of industrial enterprises.

    3.3 Physicochemical Performance Parameters (Suitable for Industrial Production and Storage)

    Parameter Name	unit	Standard Value	Detection Method
    Bulk density	g/cm³	0.70-0.90	Bulk Density Method
    Moisture content	%	≤1.0 (powder form); ≤0.8 (granular form)	Drying and weighing method
    Ash content	%	≤0.3	Ignition method
    Stability	-	Stored at room temperature for 12 months without significant performance degradation.	Constant temperature storage test
    toxicity	-	Non-toxic and non-irritating, complying with industrial environmental protection and safety standards	Acute toxicity test
    Temperature resistance range	℃	5-60 (prone to decomposition beyond this range)	Constant Temperature Test Method
    Corrosiveness	-	Slightly corrosive, no obvious corrosion to ordinary carbon steel and plastics	Corrosion Test Method

    3.4 Packaging Specifications (Adapted to Industrial Storage and Transportation Requirements)

    Packaging Type	Packaging Material	Specification per package	Weight per package	Applicable industrial scenarios
    Conventional woven bag packaging	Laminated woven bag (lined with PE waterproof membrane)	45×75cm	25kg per bag	Small-batch procurement, small industrial enterprises, laboratory use
    ton bag packaging	High-strength laminated ton bag (lined with waterproof membrane)	100×120cm	1000kg per bag	For bulk procurement, use in chemical industrial parks, large paper mills, and water supply plants.
    Customized industrial packaging	Industrial-grade waterproof woven bags and sealed plastic buckets	Customized as needed	50kg, 100kg, etc.	Fine chemicals, special industrial scenarios, long-term storage requirements

    Note: 1. The shelf life is 12 months. The product shall be stored under conventional industrial storage conditions (dry, ventilated, cool, and away from light), with the temperature controlled at 5-30℃. Keep it away from moisture, direct sunlight, rain, extrusion, oxidizing agents, strong acids and strong alkalis to prevent moisture absorption, caking and decomposition of the product, which may affect its industrial application effect. 2. All packages are marked with industrial-grade product labels, containing complete information such as product name, specification, grade, purity, iron content, production date, shelf life, manufacturer, contact information and implementation standards, facilitating inventory management and quality traceability for industrial enterprises.

    IV. Product Quality Standards (Exclusive for Industrial Grade, in strict compliance with national/industrial standards, full-process control)

    Industrial-grade solid iron-free aluminum sulfate strictly complies with relevant national and industrial standards. In response to the stringent requirements of industrial production, a rigorous internal quality control system has been established. Full-process quality monitoring is implemented from raw material selection and production to finished product delivery, ensuring high product purity, stable performance, and freedom from iron contamination. It is suitable for industrial production and environmental protection acceptance. The specific quality standards are as follows:

    4.1 Quality Compliance Standards (Focus on Industrial Sector)

    • National Standards:
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      • GB/T 31510-2015 *Inorganic Chemical Products - Aluminum Sulfate*: This standard specifies the classification, requirements, test methods, marking, packaging, transportation, and storage of aluminum sulfate. It clarifies the core indicator requirements for industrial-grade products, including purity, iron content, and water-insoluble matter, and serves as the core basis for the production and inspection of industrial-grade products.
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      • GB 8978-1996 *Integrated Wastewater Discharge Standard*: For iron-free aluminum sulfate used in industrial wastewater treatment, it specifies requirements for indicators such as iron content, heavy metal content, and arsenic content, ensuring that industrial wastewater meets discharge standards after treatment.
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      • GB 5085.3-2007 *Identification Standards for Hazardous Wastes - Identification for Extraction Toxicity*: Ensure that no harmful components leach out from the product, that it does not cause secondary environmental pollution after use, and that it meets the requirements of industrial environmental protection governance.
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    • Industry Standards:
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      • HG/T 2225-2018 *Aluminum Sulfate for Industrial Use*: For industrial-grade iron-free aluminum sulfate, it specifies the indicator requirements for products of different grades in detail, which is suitable for industrial scenarios such as industrial wastewater treatment and papermaking, and serves as an important basis for the production of industrial-grade products.
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      • QB/T 2623.1-2011 *Sizing Agent for Papermaking - Aluminum Sulfate*: Specifically for aluminum sulfate used in the papermaking industry, it specifies indicators such as iron content and flocculation performance, prevents paper contamination, and meets the production requirements of the papermaking industry.
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    • Enterprise Internal Control Standards:
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    • Based on national and industrial standards, we further raise the requirements for key indicators of industrial-grade products. For example, the iron content shall be ≤0.004% for conventional industrial grade and ≤0.002% for high-purity industrial grade. Meanwhile, special testing indicators including flocculation effect, dissolution rate and corrosivity are added to ensure that product performance exceeds the industry average and meets the stringent demands of various industrial scenarios.

    4.2 Raw Material Quality Standards (Industrial-grade raw materials, controlling purity from the source)

    Raw materials are the core factor determining the purity and performance of industrial-grade products. We strictly select high-quality industrial-grade raw materials, establish a raw material access and testing mechanism, prevent unqualified raw materials from entering the site, and ensure the stability of industrial production. The specific requirements are as follows:

    
    

    • Core raw materials (sulfuric acid, aluminum hydroxide): Industrial-grade high-purity sulfuric acid (purity ≥98%) and aluminum hydroxide (purity ≥99.5%) are selected, with an iron content ≤0.001%, free of impurities and odors, ensuring sufficient reaction, reducing iron impurities in the finished product, and meeting the purity requirements of industrial-grade products.
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    • Auxiliary materials: National standard-compliant industrial-grade environmentally friendly auxiliary materials (such as iron removal agents and stabilizers) are adopted, which contain no toxic or harmful components and have an extremely low iron content. They feature good compatibility with core raw materials, do not affect the purity and performance of the product, and avoid introducing new impurities, thus ensuring safe industrial application.
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    • Raw Material Inspection: After each batch of raw materials enters the site, indicators such as purity, iron content and impurity content must be tested. Unqualified raw materials are strictly prohibited from entering the site, so as to guarantee the quality of industrial-grade products from the source and avoid abnormalities in industrial production processes caused by raw material issues.

    4.3 Quality Standards for the Production Process (Industrial-Grade Production, Full-Process Control)

    Strictly follow the industrial-grade production process of "Raw Material Screening → Ingredient Mixing → Reaction Synthesis → Iron Removal → Crystallization → Centrifugal Dehydration → Drying → Pulverization and Sieving → Finished Product Inspection → Packaging and Warehousing". Clear quality control standards are established for each step to ensure stable product quality, as detailed below:

    
    

    • Ingredient Mixing: Mix sulfuric acid, aluminum hydroxide, and auxiliary materials in precise proportions, with a mixing uniformity ≥99.5%. Control the temperature and pH value of the reaction system to ensure stable reaction, avoid problems such as uneven local reaction and residual impurities, and meet the requirements of large-scale industrial production.
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    • Reaction Synthesis: A low-temperature synthesis process is adopted, with the reaction temperature controlled at 60-80℃. The reaction time is adjusted according to the product purity to ensure sufficient reaction. The generated aluminum sulfate crystals are uniform without residual unreacted raw materials, improving the purity of industrial-grade products.
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    • Iron removal treatment: A core process step that employs multiple iron removal technologies (such as precipitation iron removal and adsorption iron removal) to eliminate iron impurities from the reaction solution, ensuring the iron content meets the standard requirements for industrial-grade products of corresponding levels. This is a key step distinguishing it from ordinary industrial aluminum sulfate and also the core guarantee for iron-free pollution of industrial products.
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    • Crystallization and Centrifugal Dehydration: Cool and crystallize the reaction solution after iron removal, controlling the crystallization rate and temperature to ensure uniform crystals and high purity. Remove moisture from the crystals via centrifugal dehydration, controlling the moisture content at ≤1.0% to prevent moisture absorption and caking of the product, facilitating industrial storage and transportation.
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    • Drying, Pulverizing and Sieving: Feed the dehydrated crystals into drying equipment, with the drying temperature controlled at 100-120℃. Adjust the drying time according to the crystal size to ensure the product moisture content meets the standard. After pulverization, screen out products with corresponding particle sizes based on the user's industrial working conditions. The sieving qualification rate shall be ≥99%. Impurities and agglomerated products are removed to ensure uniform particle size, suitable for on-site industrial dosing applications.
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    • Intermediate Inspection: Intermediate inspections are conducted at each production stage. For example, purity and iron content are tested after the reaction; iron content is tested after iron removal; moisture content is measured after drying; and particle size distribution is analyzed after sieving. Non-conforming products must be reprocessed to ensure quality standards are met at each stage, prevent substandard products from entering the next process, and guarantee the stability of industrial production.

    4.4 Finished Product Inspection Standards (Industrial-grade Inspection, 100% Qualified before Delivery)

    Before delivery, each batch of industrial-grade products shall be subject to sampling inspection with a 100% inspection coverage rate. Non-conforming products are strictly prohibited from leaving the factory. The inspection items and qualification standards are as follows. Meanwhile, CMA/CNAS certified inspection reports can be provided to meet the quality audit and environmental protection acceptance requirements of various industrial users:

    
    

    • Appearance Inspection: The product shall be a white or off-white crystalline powder/granule with uniform granules, no caking, no impurities, and no peculiar smell. It shall have uniform color without obvious color difference. The particle size shall meet the user's industrial working condition requirements with an error ≤5%. There shall be no black spots or colored granules visible to the naked eye, which directly reflects the iron-free advantage and ensures no process abnormalities caused by appearance impurities during industrial application.
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    • Core Purity Inspection: Core indicators including Al₂(SO₄)₃ content, iron content, water-insoluble matter content, chloride content, etc., shall meet the standard requirements of corresponding industrial-grade products, with a deviation ≤2%; among them, iron content is a key inspection indicator to ensure no iron contamination and avoid affecting the quality of industrial finished products and the effect of wastewater treatment.
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    • Physical and chemical performance testing: indicators including bulk density, moisture content, ash content, water solubility, stability, corrosiveness, etc., shall meet standard requirements. Among them, moisture content ≤ 1.0%, ash content ≤ 0.3%, and no obvious performance degradation after 12 months of storage at room temperature, so as to ensure convenient industrial storage, transportation and application of the product and reduce wear and tear of industrial equipment.
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    • Environmental and Safety Testing: Safety indicators such as heavy metal content and arsenic content must comply with the standard requirements for corresponding industrial-grade products. The product is non-toxic and non-irritating, with leaching toxicity conforming to the GB 5085.3-2007 standard. It releases no harmful components and will not cause harm to the environment or human health after use, meeting the requirements of industrial environmental protection governance.
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    • Packaging Inspection: The packaging shall be intact, free from damage and leakage, with complete label information (including product name, specification, grade, purity, iron content, production date, shelf life, manufacturer, contact information, implementation standards, etc.); the packaging material shall meet industrial-grade requirements, with qualified moisture-proof, extrusion-resistant and sun-proof performance, ensuring that the product is not damaged or contaminated during transportation and storage, and adapting to the needs of industrial batch storage and transportation.

    4.5 Quality Traceability and After-Sales Standards (Tailored to Industrial User Requirements)

    • Quality Traceability: A unique traceability code is established for each batch of industrial-grade products, recording details such as raw material batch, production process parameters, intermediate test results, finished product inspection reports, delivery date, and transportation information. Full-process traceability is achievable, facilitating the investigation and resolution of quality issues for industrial users and ensuring the continuity of industrial production.
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    • After-sales Support: In the event of quality issues after product delivery (such as non-compliant purity, excessive iron content, damaged packaging, caking, etc.), customers are entitled to return or exchange services by presenting inspection reports and purchase certificates. Meanwhile, professional industrial technical guidance is provided to assist users in product selection, dissolution, and dosing application, solving various problems encountered during industrial use (such as poor flocculation effect, slow dissolution rate, equipment corrosion, etc.). Product parameters will be adjusted according to users' industrial working conditions to ensure application performance, helping industrial enterprises improve production efficiency and reduce production costs.

    • V. Multi-dimensional Image Display Instructions

      5.1 Product Detail Images

      • Overall appearance diagram:
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      • Packaging Morphology Diagram:
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      • Ton bag appearance diagram:
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      • Vehicle Transportation Diagram:
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