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Hazard Information

Material Safety Data Sheet(MSDS)

Questions And Answer

• General description

  Potassium dichromate (Formula K2Cr2O7) will be decomposed and releases oxygen under the white heat temperature. It has strong oxidizing property, being a strongly toxic and carcinogenic oxidant. It appears as orange-red solid at room temperature and plate crystal. It has been classified as a Category I carcinogen by the International Agency for Research on Cancer (IARC), and may be combustible when come into contact with combustibles. At temperature above 500 ° C, it can lead to oxidation to generate chromic acid and chromium oxide. Potassium dichromate has very small solubility at low temperature and does not contain crystal water. It is easily purified through recrystallization; also not easy to have deliquescence and thus often being used as the reference standard in the analysis.
  Owing to the strong oxidizing properties of potassium dichromate under acidic conditions, it is commonly used in the laboratory to formulate a chromic acid washing agent (a mixture of saturated potassium dichromate solution and concentrated sulfuric acid) for washing the chemical glassware in order to remove the reductive dirt in the glass wall. After use, the washing agent changes from dark red to green color under which the washing agent becomes invalid. Potassium dichromate can also used be in analytical chemistry, commonly used to determine the reductive hydrogen sulfide, sulfurous acid, ferrous ions and so on. Upon the heating, potassium dichromate can also oxidize concentrated hydrochloric acid to release chlorine.
  As the raw materials for the production of leather hydrolysates are mainly from the corner of the tannery factory waste, and these wastes often contain potassium dichromate and sodium dichromate, during the production of hydrolyzed protein, potassium dichromate, sodium dichromate will be naturally brought into the dairy products. Human drinking can lead to joint osteoporosis, swelling and other poisoning problems. Chroming workers subjecting to repeated or long-term exposure to low concentrations of chromium compounds can get chronic upper respiratory tract inflammation, chrome rhinopathy, contact dermatitis and rash which mainly occur in naked places such as the face, neck, hands and forearm. It can also cause kidney and liver damage as well as causing blood system changes. The occurrence of lung cancer has a incubation period of 10-20 years.
  
  Figure 1 the molecular structure of the potassium dichromate;

• Defination

  Potassium bichromate is an odorless substance that can be found naturally occurring in the environment, for instance, in ash, sand, loam, and clay. The chemical occurs in steel-made tools, and chrome-plated objects such as needles, silverware, handles, and bracelets. Furthermore, potassium dichromate is used as a component of fur-tanning agents, leather, dark textile dyes, epoxy hardeners, chromium pigments, and photographic color developer. The orange-red color powdered substance has a melting point of 398oC and a molecular weight of 294 gram (g)/mol. Notably, the chemical is soluble in water and ethyl alcohol. ;

• Production

  The production of potassium bichromate begins with the reaction of chromium trioxide and potassium hydroxide in a reactor generating a mother liquor.
  2 CrO3 + 2 KOH = K2Cr2O7 + H2O
  The next step is filtration of the mother liquor and the ensuing filter solids are put aside for disposal. The remaining substance is then sent for precipitation of crystalline potassium bichromate through a centrifugation process. Finally, the mother liquor from the centrifuge is sent back to the reactor. ;

• Application

  Potassium bichromate is an inorganic oxidizing agent that has multiple scientific and industrial uses.
  Photography
  Potassium bichromate has significant uses in photographic screen-printing and photography where together with strong mineral acid, they can be used as an oxidizing agent. In the 1850s, gum bichromate printing was largely used in the photographic printing processes. It is worth noting that when exposed to ultraviolet light, a solution of potassium bichromate and gum Arabic will be dried and hardened. Together with concentrated hydrochloric acid (HCL), photochromos and chromium uses potassium bichromate to treat thin and weak negatives of black and white photograph roll. The solution of HCL together with potassium bichromate reconverts the particles of silver in the film to silver chloride. The film is the exposed to actinic light and then redeveloped to its end product, giving out a more stronger negative and a acceptable print. In sulfuric acid, potassium bichromate solution can be used to manufacture a reversal negative.
  Industrial Uses
  Manufacturers in the textile industry use the chemical in dying clothe fabrics and tanning leather. In addition, potassium bichromate is normally used in decorative chromium plating as well as coating active metals such as steel and aluminum to prevent them from corrosion. In science, the substance is used as a solvent and in the identification of certain elements in solutions. In the furniture industry, the chemical is used in straining wood. ;

• Health Effects

  Acute Health Effects 
  Potassium bichromate, similar to other chromate compounds can cause acute health effects if inhaled or ingested. The chemical can cause irritation in the lungs or throats of some individuals. Chrome fumes and dust are irritating to the lungs and respiratory tract. Toxic effects due to over exposure may lead to asthmatic conditions. Accidental ingestion of the chemical may lead to toxic effects. 
  Potassium bichromate may result to chemical burns within the gastrointestinal tract and oral cavity if swallowed. It is noteworthy that acute poisoning from the substance is minimal since vomiting or renal excretion occurs immediately after swallowing. However, swallowing the chemical can lead to extreme thirst, loss of appetite, fever, augmented volumes of urine, gastric imbalances, and convulsions. Due to failure of breathing and inflammation of the bowel and the stomach, an individual can die following the swallowing of potassium bichromate. 
  Following direct contact to the eye, the chemical can produce burns and cause severe damage. If in contact with the skin and absorbed, potassium bichromate may lead to chemical burns. In addition, chrome fumes such as chrome oxide may exacerbate current skin conditions, for instance, eczema or dermatitis, and can lead to severe damage to the skin. Also, absorption through the skin may lead to poisoning affecting the liver and kidneys. It is essential to note that the substance should not come to contact with open cuts, lesions, or abrasions as it may produce systemic injuries if it enters the blood stream. 
  Chronic Health Effects
  Potassium bichromate is a mutagen and a carcinogen, therefore can cause cancer in humans due to prolonged exposure. In addition, lengthy exposure inside the mouth can lead to ulcerative and inflammatory changes in the mouth and erosion of the teeth. Recurrent attach of bronchial pneumonia and the gastrointestinal disturbances may ensue. Inhalation and skin contact with potassium bichromate may result to sensitization reaction is particular individuals. Interestingly, the substance can lead to genetic defects as well as reduced fertility in humans.  ;

• Waste Disposal

  No waste solutions of potassium chromate should be drained, as they can cause detrimental effects to the environment. In addition, all powdered materials should be disposed as hazardous waste. Generally, all disposable materials as well as decontamination from non-disposable tools or equipment must be disposed ass hazardous waste. ;

• References

  1. https://nj.gov/health/eoh/rtkweb/documents/fs/1564.pdf
  2. http://datasheets.scbt.com/sc-203353.pdf
  3. http://archived.materials.drexel.edu/Safety/SOP/sop_potassium_dichromate.pdf
  4. Jessica Jacobs. What Is Potassium Chromate Used For? https://www.livestrong.com/article/1013080-livestrongs-future-food-chef-dinner-chef-tal-ronnen-impossible-burger/
  5. https://archive.epa.gov/epawaste/hazard/web/pdf/pot-dich.pdf
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