Ammonium Sulfate
Ammonium sulfate ((NH₄)₂SO₄) is an important inorganic chemical raw material and high-quality nitrogen fertilizer, widely used in agriculture, electroplating, chemical synthesis, and pharmaceutical intermediates. Its purity, particle size, and moisture content directly determine its application efficiency and market competitiveness. Tianli specializes in the refined production of ammonium sulfate, focusing on optimizing two core processes: commonly used evaporation crystallization and internally heated fluid bed drying. Leveraging our comprehensive technological advantages, we create high-purity, low-energy-consumption, and environmentally friendly ammonium sulfate products to fully meet the stringent production needs of various industries and contribute to high-quality industrial development.
I. Core Properties of Ammonium Sulfate
Ammonium sulfate is a white crystalline powder or granules with the molecular formula (NH₄)₂SO₄, a relative molecular mass of 132.14, a density of 1.77 g/cm³, and a melting point of 280℃ (decomposes). It is odorless, has a cool, salty taste, low hygroscopicity, does not easily clump, and exhibits good storage stability. Its aqueous solution is weakly acidic, and its solubility changes gradually with temperature. At 0℃, the solubility is 70.6 g/100 g water, and at 100℃, it reaches 103.8 g/100 g water. This characteristic is the core basis for designing evaporation crystallization process parameters. Ammonium sulfate is stable at room temperature, but decomposes into gases such as ammonia and sulfur dioxide when heated above 280℃. It is readily soluble in water but insoluble in ethanol and acetone. The raw material is widely available and can be obtained through the neutralization of ammonia and sulfuric acid, as well as industrial by-product recovery, making it suitable for large-scale production.
II. Core Process Flow Introduction
(I) Common Evaporation Crystallization Process for Ammonium Sulfate: High-Efficiency Concentration and Precise Crystallization
The evaporation crystallization stage is the core concentration and crystallization step in ammonium sulfate production. Its core purpose is to efficiently remove moisture from the pretreated ammonium sulfate solution through evaporation, bringing the solution to a supersaturated state and precisely precipitating crystals, thus balancing production efficiency and product purity. Our company adopts the industry-standard multi-effect evaporation crystallization process, combined with a forced circulation evaporator and a high-efficiency crystallizer, adapted to the solubility characteristics of ammonium sulfate, to achieve large-scale, high-efficiency production.
The process flow follows the core logic of raw material pretreatment - multi-effect evaporation - crystallization separation - mother liquor circulation: the raw material solution is filtered, impurity removed, and pH adjusted to remove mechanical impurities and harmful components, ensuring the purity of the solution; the pretreated solution sequentially enters the multi-effect evaporator. Live steam is introduced into the first effect as a heat source, and subsequent effects utilize the secondary steam generated in the previous effect for heating, achieving heat energy recycling and reducing energy consumption. The evaporator operates at a controlled temperature of 100-110℃ under negative pressure. The feed liquid flows at high speed in a forced circulation system to prevent localized overheating and scaling. After concentration to saturation, it is sent to the crystallizer. Through seed induction and grading, uniformly sized ammonium sulfate crystals are precipitated. After centrifugation, wet ammonium sulfate crystals are obtained. The mother liquor is returned to the evaporation system for recycling, achieving a raw material utilization rate of over 98%.
(II) Internally Heated Fluid Bed Drying Section: High-Efficiency Dehydration and Stable Formation
The internally heated fluid bed drying section handles the wet ammonium sulfate crystals after evaporation and crystallization. Its core task is to remove free moisture from the crystal surface, ensuring the moisture content meets the GB/T 535-2020 standard (≤0.2%). This guarantees intact crystal morphology, prevents clumping, lowers product temperature, facilitates subsequent packaging, storage, and transportation, and further improves product quality.
Tianli uses an internally heated fluid bed drying unit, adapted to the drying requirements of ammonium sulfate. Wet crystals are evenly fed into the dryer via a sealed feeder. Utilizing both built-in heating elements and hot air, the hot air is pressurized in the air chamber, suspending the material and creating fluidized state. The material continuously tumbles, ensuring uniform drying. The internal heating design significantly improves heat utilization efficiency and reduces heat loss, resulting in significant energy savings compared to traditional drying equipment. It also precisely controls the drying temperature, preventing thermal decomposition of the ammonium sulfate. After drying, the ammonium sulfate crystals are cooled and screened for impurity removal, ultimately yielding a finished product with a purity ≥99.5%. Dust-laden gas is treated in two stages—a cyclone separator and a wet dust collector—before being discharged in compliance with standards, achieving clean production.
III. Core Technological Advantages
1. Technological Advantages: utilizing a mature multi-effect evaporation crystallization process coupled with a forced circulation system, it effectively prevents equipment scaling and crystal agglomeration. The internally heated fluid bed combined with a dual heating mode improves drying efficiency by over 30% compared to traditional equipment. The mature and stable process is suitable for large-scale continuous production, and the equipment is easy to maintain with a low failure rate.
2. Energy Consumption Advantages: multi-effect evaporation fully recovers and utilizes secondary steam, improving thermal energy utilization by over 60% compared to single-effect evaporation. The internal heating design reduces heat loss, resulting in an overall energy consumption reduction of 25%-30% compared to traditional processes, significantly lowering production costs and improving economic efficiency.
3. Environmental Advantages: the entire process employs a closed-loop design, recycling the mother liquor and eliminating wastewater discharge. The evaporation and drying processes are entirely closed, with a two-stage dust removal system, resulting in dust emission concentrations below industry standards and no harmful gas generation. This aligns with green and low-carbon production principles and meets environmental emission requirements.
4. Product Advantages: through precise control of evaporation, crystallization, and drying parameters, the product purity is ≥99.5%, with uniform crystal size, complete crystal form, stable moisture content, no impurity residue, low hygroscopicity, and resistance to clumping. It is suitable for various specifications in agriculture, chemical, and pharmaceutical fields, and its quality far exceeds industry standards.
5. Control Advantages: equipped with a fully automatic DCS control system, it can monitor key parameters such as feed concentration, evaporation temperature, and drying moisture content in real time, achieving precise process control, convenient operation, reduced manual intervention, lower human error, and ensuring stable production and consistent product quality.
Technology empowers quality, professionalism creates value. Our company focuses on the characteristics of ammonium sulfate, deeply cultivating core technologies in evaporation crystallization and internally heated fluid bed drying. Leveraging our comprehensive advantages in technology, energy consumption, and environmental protection, we provide high-quality ammonium sulfate products and one-stop production solutions to various industries, working hand in hand with customers to promote industrial upgrading and achieve mutual benefit.