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1. Differences in ingredients and production processes
Iron content difference

Red flake sodium sulfide: The iron content is relatively high, usually 150PPM or 1500PPM (some specifications reach 0.15%), and it is red or reddish brown due to the iron impurities. The production process is mostly traditional coal powder reduction method, and the raw materials may contain a high iron content.

Yellow flake sodium sulfide: The iron content is extremely low, divided into multiple grades such as 10PPM, 20PPM, 50PPM, etc., and the appearance is yellow or light yellow. It needs to be refined or the production process improved (such as adding an iron removal process) to achieve low iron characteristics, which is suitable for fields that are sensitive to iron impurities.

Other Ingredients
The sodium sulfide content of both is ≥60%, but the upper limit of sodium carbonate (Na₂CO₃) and water-insoluble matter in the red tablets is higher (such as sodium carbonate ≤5%), while the requirements for yellow tablets are more stringent (such as sodium carbonate ≤2%).

2. Price and Market Positioning
Price difference: Due to the complex production process and strict control of iron content, the market price of yellow tablets is usually 100-150 yuan/ton higher than that of red tablets.

Market positioning: Red films are mostly used in industrial scenarios that do not require high iron content (such as water treatment and mineral processing), while yellow films are positioned at the high end and are suitable for the fields of pharmaceuticals, fine chemicals, etc.

3. Differences in usage
Typical uses of red flake sodium sulfide

Water treatment: The iron content must be ≥1500PPM to effectively remove heavy metal ions, suitable for wastewater treatment.

Metallurgy and mineral processing: As an ore flotation agent, its oxidizing properties are used to improve metal separation efficiency.

Papermaking and leather making: used as cooking agent and dehairing agent, with no special requirements for iron content.

Core Application of Yellow Tablet Sodium Sulfide

Pharmaceutical industry: When synthesizing drugs such as phenacetin, it is necessary to avoid interference from iron ions. The low iron properties of yellow tablets (≤50PPM) meet the pharmacopoeia standards.

High-end chemicals and dyes: used to produce high-purity sulfur dyes (such as sulfur cyan, sulfur blue) and organic intermediates to ensure color and reaction stability.

Electronics and electroplating: In circuit board etching or conductive layer processing, low iron yellow flakes can reduce the impact of impurities on the process.

4. Safety and storage requirements
Both are highly corrosive and toxic and need to be sealed and stored away from light to avoid contact with acid. Red tablets have a high iron content and oxidize faster, so they need to be more strictly protected from moisture; yellow tablets must be packaged intact during transportation to prevent contamination.

V. Development Trend
As environmental regulations become stricter, the demand for low-iron yellow tablets is growing, especially in the pharmaceutical and fine chemical fields. However, red tablets still dominate in traditional industries due to their cost advantages. Companies can improve the purity of yellow tablets by optimizing production processes (such as gas reduction method) or develop multi-specification products to meet the needs of market segments.