Great Spring: Chromium Oxide Green Factory with Great Quality
What is chromium oxide green ?
Chromium oxide green ‘s scientific name of is chromium trioxide, also known as “chromium oxide”. It is a dark green crystalline powder with metallic luster. It belongs to the hexagonal crystal system or the trigonal crystal system. It is the same crystal form as α-alumina. It has a chemical formula of Cr2O3 and a molecular weight of 151.99. , relative density 5.21. It is harder than quartz and steel, with a melting point of 1990°C and a boiling point of over 3000°C. Its chemical properties are extremely stable.
Magnetic. Insoluble in water and alcohol. Chromium oxide green that has been burned at high temperature is inert to acids and alkalis, but can be eutectic with acidic fluxes and transformed into soluble chromium (Ⅲ) salts. Soluble in hot alkali metal bromate solutions. Chromium oxide green is a common green pigment. Its color can range from bright green to dark green. It has excellent light resistance, heat resistance, chemical corrosion resistance and other properties. It has high hiding power, but has a darker color.
Chromium oxide green is a green solid with corundum structure, also known as chrome green.
Chromium oxide green is also called “chromium oxide”, commonly known as “chrome green”. Dark green hexagonal crystal or amorphous powder. The melting point is 2435°C, the boiling point is 4000°C, the relative density is 5.21, and the refractive index is 2.551.
Its hydrate is commonly known as “hydrochrome green” and is a purple amorphous crystal or a blue-gray-green gel. Insoluble in water, acid and alkali, soluble in hot potassium bromate solution. The properties are extremely stable and will not change even when hydrogen is introduced at high temperatures.
Preparation method: obtained from the reaction of sodium dichromate and sulfur, or from the thermal decomposition of chromium hydroxide and ammonium dichromate. Usage: Used as green pigments, organic synthesis catalysts, ceramic glazes, paint raw materials and raw materials for making chromium alloys and chromium salts.
Advantages of chromium oxide green pigment products
1. Bright color, high tinting power and hiding power.
2. Chromium oxide green is resistant to high temperatures and sunlight, is easily soluble in water, and is difficult to dissolve in acid. It is relatively stable in the atmosphere and has no effect on general concentrations of acids, alkalis and sulfur dioxide gas. It has excellent pigment quality and fastness.
3. The infrared reflection of purer products is close to that of natural chlorophyll.
4. The company independently develops and produces products with wide range of uses, low prices, multiple equipment testing, and fine finished products to ensure product quality.
The main uses of chromium oxide green pigment
1. Chrome green is often used to make pigments for green paints, ceramics, etc., and can also be used as a catalyst for organic synthesis (such as the production of polyethylene and butadiene).
2. Chromium oxide green is mainly used to smelt metallic chromium. It can also be used as a pigment in paints and ceramics, a catalyst for organic synthesis, and is also used to make abrasive materials, green polishing pastes and inks.
3. As a green pigment, chromium oxide green can be used in printing inks and coatings. In addition, it is widely used as a colorant in glass, ceramic tiles, ceramic vessels, etc. It can also be used as a greasy abrasive material such as green oil in chrome plating. Used for grinding the bottom plate and polishing the surface when plating nickel.
4. The powder itself can be used as a fine grinding material for the manufacture of metal and glass products. It can also be made into chromium-magnesium or magnesium-chromium refractory bricks, and can be used as raw material for metallic chromium.
Chromium oxide green factory: Storage and transportation conditions of chromium oxide green
1. Packed in multi-layer kraft paper bags and stored in a ventilated and dry warehouse.
2. Pay attention to moisture and high temperature.
3. Do not mix with acid and alkali items.
4. According to the above storage conditions, the effective storage period of unopened products is 3 years.
Chromium Oxide Green Factory
Our chromium oxide green factory quality control
1. In accordance with the ISO9001 quality system, chromium oxide green factory adopts ISO1248 and EN12878 quality standards, and has developed complete raw material control and strict production control, a sophisticated detection system and a detailed identification and tracking system to ensure the consistency of the quality of iron oxide pigments.
2. Quality assurance system: ISO9001:2008
3. Product quality standards: ISO1248, EN12878
1. Cr2O3 is amphoteric and can react with acids and bases:
Cr2O3+ 3H2SO4= Cr2(SO4)3+3H2O
Cr2O3+ 2NaOH = 2NaCrO2 +H2O
2. Cr2O3 reacts with potassium pyrosulfate at high temperature:
Cr2O3+ 3K2S2O7= 3K2SO4+ Cr2(SO4)3
[Preparation of Chromium Oxide Green by Sodium Dichromate Method]
Chromium oxide green (Cr2O3) is the main raw material for the production of metallic chromium. Cr2O3 is produced from chromite by chemical metallurgical methods.
First, chromite is oxidized and roasted to obtain sodium chromate (Na2CrO4) dissolved in water, which oxidizes the trivalent chromium in the chromite into hexavalent chromium. After water leaching, a sodium chromate solution is obtained, from which the sodium chromate solution can be used to produce chromium trioxide using the sodium dichromate method and the chromium hydroxide method.
Method for preparing chromium oxide green by reducing sodium dichromate with ammonium chloride. Sodium dichromate and ammonium chloride are mixed according to the calculated ingredient ratio (practice has proven that when the amount of ammonium chloride is about 140% of the theoretical amount, the conversion rate can reach 95-96%), and then placed in a reverberatory furnace with a flame isolation Reduction is carried out in the chemical reaction formula:
After the reaction is completed, the charge is put into a washing tank with a stirrer and washed several times with hot water to remove sodium chloride. Then use a filter press to filter to obtain a paste-like chromium trioxide filter cake containing 30-35% moisture. After drying (temperature 300°C), calcining at high temperature, cooling and crushing, the finished product is obtained.
The finished product contains Cr2O3 (97%-98%). In addition to using NH4Cl to reduce sodium dichromate to produce Cr2O3, sulfur, charcoal, etc. can also be used to reduce Na2Cr2O7 to produce chromium oxide green. Its chemical reaction formula is:
[High-temperature calcination of chromium trioxide]
Place chromium trioxide in a calcining furnace (a rotary kiln can also be used) for high-temperature calcining, and the combustion zone temperature shall not be lower than 1300°C. The calcining furnace is composed of three muffle furnaces that are not on the same plane and are in a stepped shape (the muffle furnace is made of silicon carbide bricks).
The sulfate in chromium trioxide (prepared by the sodium dichromate method) is converted into metal oxides by calcination, and the sulfur is volatilized as sulfur dioxide gas.
This is an important measure to improve the quality of metallic chromium. Calcining temperature and calcination time are the main factors affecting the calcination rate. High-temperature calcination can produce chromium trioxide with low sulfur (S) and low lead (Pb).
Respiratory protection: Use appropriate respirator.
Eye protection: Wear dust glasses and face shield.
Body protection: Wear protective clothing, gloves, boots, and helmets, clean and change them every day.
Skin contact: Wash with soap and water for 5 minutes.
Eye Contact: Flush with plenty of water for at least 15 minutes; seek medical advice.
Inhalation: Move the patient to fresh air, give oxygen or perform artificial respiration.
Chromium oxide green factory competitiveness
1. Price advantage: The chromium oxide green factory supply price for products of the same quality and quality is generally lower than 0.8 to 0.2 yuan compared with other companies.
2. Chromium oxide green factory have a large warehouse of 30,000 square meters, with sufficient inventory of finished products and raw materials.
3. The chromium oxide green factory has more than 200 employees, and more than 50 employees are responsible for receiving and issuing orders. It can handle a large number of orders with high efficiency.
4. The chromium oxide green factory has long-term stable cooperation with major express delivery and logistics companies, and the delivery time is faster!
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