Sodium Bicarbonate (Baking Soda) Refined Production Solution

Sodium bicarbonate (NaHCO₃), commonly known as baking soda, is a widely used inorganic chemical product. It is extensively used in food processing, pharmaceutical preparations, feed additives, water treatment, and fire protection. Its purity, whiteness, and stability directly determine its application value. Tianli specializes in the refined production of sodium bicarbonate, focusing on optimizing two core processes: metathesis reaction synthesis and internally heated fluidized bed drying. Leveraging advanced technology, we produce high-purity, low-loss, and environmentally friendly sodium bicarbonate products to comprehensively meet the stringent production needs of various industries.

I. Core Properties of Sodium Bicarbonate

Sodium bicarbonate is white crystalline powder with the molecular formula NaHCO₃, relative molecular mass of 84.01, density of 2.159 g/cm³, and melting point of 270℃ (decomposes). It is odorless with slightly salty taste and slightly hygroscopic feature. When exposed to air, it slowly decomposes to form sodium carbonate, water, and carbon dioxide. Its aqueous solution is weakly alkaline, and its solubility increases significantly with increasing temperature—6.9 g/100 g water at 0℃ and 16.4g/100g water at 60℃. This characteristic is a key basis for controlling the crystallization of the metathesis reaction and designing the drying process. Sodium bicarbonate decomposes easily when heated and reacts rapidly with acids to release CO₂. It has a wide range of raw material sources and is suitable for large-scale continuous production.

II. Core Process Flow Introduction

1. Double decomposition reaction synthesis section: precise crystallization and efficient purification

The double decomposition reaction is the core synthesis step in the production of sodium bicarbonate. Using sodium chloride and ammonium bicarbonate as raw materials, sodium bicarbonate crystals are generated by precisely controlling the reaction conditions, while the byproduct ammonium chloride is recovered simultaneously, achieving integrated efficient utilization of raw materials and product purification.

Process flow:

(1) Raw material pretreatment: sodium chloride is dissolved and filtered to remove mechanical impurities and calcium and magnesium ions, resulting in pure saturated brine.

(2) Double decomposition reaction: ammonium bicarbonate is slowly added to saturated brine according to the stoichiometric ratio. The reaction temperature is controlled at 30-35℃ and the pH value at 8.0-8.5. The stirring rate is precisely controlled to ensure that the reaction proceeds completely. The chemical reaction formula is: NaCl + NH₄HCO₃ → NaHCO₃↓ + NH₄Cl

(3) Solid-liquid separation and purification: after the reaction is completed, crude sodium bicarbonate is obtained by centrifugation, and then purified by washing with cold water and recrystallization to remove residual ammonium chloride and salt, so as to obtain high-purity wet sodium bicarbonate crystals.

(4) Mother liquor treatment and by-product recovery: the separated mother liquor (mainly containing NH₄Cl) is sent to the multi-effect evaporation system to recover ammonium chloride as an industrial by-product. The evaporation condensate is reused for raw material dissolution, realizing the material recycling use. The comprehensive utilization rate of sodium element is ≥97%, and wastewater is nearly zero.

2. Internal coil fluidized bed drying section: low temperature and high efficiency, preventing decomposition.

The drying section handles wet sodium bicarbonate crystals. Its core task is to remove surface moisture while preventing the material from decomposing due to heat, so that the moisture content of the finished product meets the GB/T 1606-2008 standard (≤0.2%), ensuring that the crystals are intact with good flowing.

Drying principle and process:

Wet crystals are uniformly fed into the internal coil fluidized bed dryer through sealed feeder. Hot air is evenly distributed through the air distribution chamber and then blown in from the bottom, causing the material particles to be in a fluidized suspension state. The built-in internal coil (through which steam is introduced) is in direct contact with the fluidized material, providing the main heat for evaporation. The dual effect of hot air fluidization + internal heating heat transfer results in a thermal efficiency much higher than that of a pure hot air fluidized bed, and steam consumption is reduced by about 30%.

Key controls: drying temperature requires strict control (short residence time, below the significant decomposition temperature of sodium bicarbonate). The dried material undergoes cooling section to prevent clumping after packaging. Dust entrained with exhaust gas is treated in two stages—cyclone and bag filter—before reaching emission standards. The final product purity can reach 99.0%~99.8% (customizable according to their requirements), with high whiteness, uniform crystals, and no impurities.

III. Core Technical Advantages

1. Efficient utilization of raw materials and controllable overall costs.

By optimizing the ratio and parameters of the double decomposition reaction, sodium chloride and ammonium bicarbonate can be fully reacted, and the comprehensive utilization rate of sodium element is ≥97%. The by-product ammonium chloride can be recovered by multi-effect evaporation and sold as an industrial raw material, which greatly reduces the unit consumption of raw materials and the overall production cost.

2. Reduced significantly energy consumption by low-temperature and high-efficiency drying

Internal coil fluidized bed dryer allow materials come into direct contact with heat exchange tubes, resulting in high heat utilization and 30% reduction in steam consumption comparing with traditional hot air fluidized bed dryer. That reduces the demand for drying media (hot air), allowing more compact equipment selection and lower civil works & equipment investment.

3. Excellent product quality and strong adaptability

By precisely controlling the reaction crystallization and low-temperature drying, the product purity is ≥99.0% (99.8% or higher can be customized), with high whiteness, uniform crystals, moisture content ≤0.2%, and no residual impurities such as ammonium chloride. It can be flexibly adapted to the different purity and particle size requirements of various fields such as food additives, pharmaceutical excipients, fire-fighting agents, and feed additives.

4. Green and environmentally friendly

The mother liquor is recovered by multi-effect evaporation to recover ammonium chloride, and the condensate is reused. There is no process wastewater discharge throughout the entire process.

The double decomposition reaction produces no harmful gases, and the drying process is operated in closed system and equipped with two-stage dust removal. The exhaust air is discharged after reaching the emission standard.

The low-temperature drying design effectively prevents product decomposition. Equipped with intelligent temperature control, pH monitoring and material level interlocking system, it can eliminate safety hazards such as reaction runaway, overheating decomposition and equipment leakage.

5. Intelligent control and flexible adaptation

The fully automated DCS control system monitors key parameters such as reaction temperature, pH value, drying temperature, and finished product moisture content in real time, precisely controlling process conditions. It can quickly adapt to different raw material batches and product specifications with features of easy operation, highly stable, less manual intervention, and improved production efficiency.