OVERVIEW
Copper fertilizers are micronutrient fertilizers used to correct copper (Cu) deficiency in crops. Copper is essential for enzyme activation, photosynthesis, lignin formation, respiration, and disease resistance. Copper fertilizers are manufactured in solid (powder/granular) and liquid forms, suitable for soil application, fertigation, and foliar spraying.
COMMON COPPER FERTILIZER TYPES
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Copper sulfate (CuSO₄·5H₂O) – most common
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Chelated copper (Cu-EDTA, Cu-DTPA) – high availability
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Copper oxide / copper hydroxide – slow-release soil use
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Liquid copper solutions – foliar and fertigation use
RAW MATERIALS USED
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Copper metal or copper oxide
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Sulfuric acid (for sulfate form)
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Chelating agents (EDTA, DTPA)
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Process water
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pH buffers and stabilizers
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Granulation binders (for granular products)
METHODS TO MAKE COPPER FERTILIZER
1. COPPER SULFATE PRODUCTION METHOD (MOST COMMON)
PROCESS PRINCIPLE
Copper or copper oxide reacts with sulfuric acid to form copper sulfate, which is then crystallized and dried.
MAIN STEPS
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Dissolution of copper metal/oxide in sulfuric acid
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Formation of copper sulfate solution
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Filtration to remove impurities
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Concentration by evaporation
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Crystallization (blue crystals)
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Drying and sizing
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Packaging
ADVANTAGES
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High copper solubility
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Rapid plant availability
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Widely accepted fertilizer grade
2. CHELATION METHOD (Cu-EDTA / Cu-DTPA)
PROCESS PRINCIPLE
Copper ions are chemically bound to a chelating agent, improving stability and uptake, especially in alkaline soils.
MAIN STEPS
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Dissolve chelating agent in water
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Add copper salt slowly under controlled pH
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Maintain agitation and temperature
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Complete chelation reaction
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Filtration and stabilization
ADVANTAGES
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Prevents copper fixation in soil
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High efficiency at low doses
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Excellent for fertigation and foliar application
3. GRANULAR COPPER FERTILIZER METHOD
PROCESS PRINCIPLE
Fine copper sulfate powder is granulated for easier handling and blending.
MAIN STEPS
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Powder blending with binder/filler
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Drum or pan granulation
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Drying
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Screening and cooling
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Anti-caking coating
ADVANTAGES
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Reduced dust
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Better compatibility with NPK blends
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Uniform field application
4. LIQUID COPPER FERTILIZER PRODUCTION
PROCESS PRINCIPLE
Copper sulfate or chelated copper is dissolved in water to form a clear, stable solution.
MAIN STEPS
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Dissolution in clean water
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pH adjustment (usually mildly acidic)
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Addition of stabilizers/surfactants
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Fine filtration
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Packaging
APPLICATION
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Foliar spraying
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Drip fertigation systems
QUALITY CONTROL PARAMETERS
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Copper content (% Cu)
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Solubility in water
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pH value
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Particle size (solid forms)
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Stability and shelf life
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Absence of insoluble residues
APPLICATION METHODS OF COPPER FERTILIZERS
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Soil application: granular or powder forms
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Foliar application: low-dose spray for quick correction
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Fertigation: chelated or liquid copper forms
PRECAUTIONS
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Copper is required in very small amounts
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Over-application can cause phytotoxicity
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Avoid mixing with incompatible alkaline products
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Follow recommended application rates
SUMMARY
Copper fertilizers are manufactured using sulfation, chelation, granulation, or liquid formulation methods. Among these, copper sulfate and chelated copper fertilizers are the most widely used due to their high efficiency and flexibility in application. Proper formulation and controlled use ensure effective correction of copper deficiency and improved crop health.
