What Is Calcium Cyanamide (Lime Nitrogen) and Why It Matters in Agriculture and Industry?

Technical Introduction

Calcium Cyanamide (CaCN₂), commonly known as Lime Nitrogen, is a gray-black crystalline powder produced by the reaction of calcium carbide with nitrogen at high temperature. It contains around 60–65% calcium cyanamide and free lime (CaO).

This compound serves as both a nitrogen fertilizer and a soil conditioner, and it also exhibits herbicidal, insecticidal, and fungicidal properties. Beyond agriculture, calcium cyanamide finds uses in the steel, chemical, and environmental protection industries due to its reactivity and versatility.

Applications

1. Agriculture

• Fertilizer: Supplies nitrogen to crops after gradual hydrolysis, ensuring slow-release nutrition.

• Soil Disinfection: Destroys harmful fungi, insects, and nematodes, reducing soil-borne diseases.

• Weed Suppression: Acts as a pre-emergence herbicide, suppressing weed germination.

• Soil Improvement: Neutralizes acidity, improving soil structure and fertility.

2. Steel Industry

• Used as a desulfurizing agent in steel production.

• Improves steel quality by reducing sulfur impurities.

3. Chemical Industry

• Intermediate for the production of dicyandiamide (DCDA), melamine, cyanamide-based pesticides, and other nitrogen compounds.

4. Environmental Applications

• Utilized in wastewater treatment for removing heavy metals and as a flocculant aid.

Advantages

• Dual Function: Works as both a fertilizer and soil disinfectant.

• Slow-Release Nitrogen: Provides crops with a steady nitrogen supply.

• Pest and Weed Control: Reduces reliance on chemical pesticides and herbicides.

• Cost-Effective: Reduces input costs by combining fertilizer and crop protection functions.

• Industrial Versatility: Essential raw material in steelmaking and chemical synthesis.

Typical Parameters

FAQs

Q1: How does calcium cyanamide release nitrogen?
A1: In soil, calcium cyanamide reacts with water to form urea and then ammonia, providing gradual nitrogen availability.

Q2: Is calcium cyanamide safe for crops?
A2: Yes, when properly applied and incorporated into soil. It should be applied before planting to allow reaction and avoid phytotoxicity.

Q3: Can calcium cyanamide reduce pesticide usage?
A3: Yes. Its disinfecting and herbicidal properties reduce soil pathogens, nematodes, and weeds, lowering pesticide needs.

Q4: What precautions should be taken when handling?
A4: It is alkaline and reactive; workers should use protective gloves, masks, and goggles, and avoid direct contact with skin or eyes.

Q5: Why is calcium cyanamide used in steelmaking?
A5: It acts as a desulfurizer, binding with sulfur impurities and improving the quality of steel.