The molecular weight of sodium polytungstate is 2986.12 g/mol and relative density is 2.8. It’s soluble in water and is a new type of inorganic heavy liquid material produced by German SOMETU Company. It’s non-toxic, tasteless, neutral stable and easy prepared. It has the incomparable advantages of high recovery rate, use security with traditional heavy liquid. Relative density can reach 3.1 in particular. Many places used the original organic heavy liquid can be instead of sodium polytungstate. Within the scope of the pH 2 ~ 14, it’s stable and can be easily recycled. It is suitable for the separation of the vast majority of oxygen oxides and salts and has been widely applied in the separation experiment of fine mineral and conodont.

 

Because of good security and convenient recycling of sodium polytungstate, it’s very popular. Although its price in the international market, its prominent advantages make it be the first choice of the heavy liquid in numerous rock ore laboratory. However, the use of the heavy liquid should be paid attention to the following points:

1. Try not to contact with strong reducing agents, otherwise the solution will become blue and influence the separation effect of observation.

2. Should not be used to contain soluble or exchangeability calcium minerals, otherwise it’s easy to form calcium polytungstate precipitation, which limits its application in the clay mineral separation.

3. Under the condition of high relative density, heavy liquid viscosity increases. To reduce the separation time, use the centrifuge or choose larger size single crystal, as far as possible to speed up the separation process.

4. The operation is unfavorable to join too many samples at a time, in order to avoid congestion heavy export of funnel.

 

How to prepare sodium polytungstate? It can be divided into the following steps:

1. When preparing sodium polytungstate, distilled water or deionized water can be used, and glass, plastic or stainless steel container can be used.

2. Measure distilled water. According to the requirements of the density value, add sodium polytungstate to the water in the container in proportion. Keep stirring with a glass rod, so that it is fully dissolved. 

3. The density of solution is measured with a hydrometer. According to the results, add distilled water or sodium polytungstate properly until suitable density value is reached.

4. Put the solution in the dust-free and closed environment to save.

5. You’d better measure the density of solution before use and make the appropriate adjustment in accordance with requirements.