BARITE (ALSO BARYTES)

Barite ( also Barytes)

Barite or barite has the chemical composition BaSO4. It has the unique distinction of having high specific gravity of 4.5, being insoluble in water and remaining comparatively unaffected by acids. Its principal use is as a weighting agent in the preparation of drilling mud. It is also found useful in the manufacture of barium chemicals and white paints. To a user extent it is used in the glass and explosive industries and as filler in rubber, leather, textile and paper goods. Barite needs to be pulverized before use in the above industries.

Specifications of barite vary according to its use in different industries. These are discussed below:

(1)        Chemical Industry:    The BIS (IS: 2881 1984) has prescribed specification for chemical industry and oil well drilling as given below:

S. No.

Characteristics

Requirement
Grade-I                                     Grade - II
Quality A     Quality B

i

Insoluble minus silica     percent by mass

97

90

90

ii

Silica (as SiO2) percent by mass

2.0

6.0*

--

iii

Aluminium a (as Al) percent by mass (max.)

0.10

--

--

iv

Iron (as Fe) percent by mass (max.)

0.10

1.5

--

v

Calcium and magnesium (as CaCO3) percent by mass (max.)

0.10

2.0

--

vi

Fineness (determined by wet method).
(a) Passing through 75-micron IS Sieve,
(b) Passing through 53 micron IS Sieve, percent by mass (max.)

--

--

--

--

97
90 + 5

vii

Relative Density at 27o / 27o C (min.)

--

--

4.15**

viii

Matter Soluble in water percent by mass (max.)

--

--

0.02

ix

Performance    

--

--

to pass test

* Silica and aluminium oxide together shall be 6.0 percent
**        For off-short drilling the value shall be 4.20

Grade I Suitable for chemical industry. The material under grade-I shall be of two qualities namely quality (A) and Quality (B)

2. Oil Well Drilling:    Grade II indicated in the above table shall be suitable for petroleum industry and oil well drilling operations.

3. Pigments for paints: The BIS has standardized specification for both natural barite and precipitated barite (IS: 64 1972). The nature barite is the Type I of the BIS that has been further subdivided in to Grade I and Grade - II. The Precipitated barite is the Type 2 of BIS. In this, the desirable parameters are BaSO4, high oil absorption, fine particle size and white to snow white color. The objectionable parameters are NaCO3, volatile matter, water solubility, etc. The specification is as follows:

   
Type - I
(Natural)
Grade - 1% Grade - 2%

Type - II
(Precipitated)
%

i

BaSO

95

95

97

ii

BaCO3 max.

2.24

2.24

0.45

iii

Volatile matter mad.

0.5

.05

0.5

iv

Residue on sieve max.

Residue on sieve max.
IS sieve (400 mesh)

0.25 on 63 micron
IS sieve (240 mesh

0.1 on 40 Micron
IS sieve (400 mesh)

v

Oil absorption

6 to 12

15 to 30

vi

Particle shape

Characteristics  of material and similar to that of approved sample.

vii

Color  

A close math to that of approval sample.

 

viii

Matter soluble in water

0.5

--

--

ix

pH of aqueous extract

6 to 8

--

x

Relative density (Sp. Gr. At 25o C)

4.45

3.36

(4) Robber Industry: Barite containing a minimum 99.5% BaSO4 is usually preferred. Such purity is not found in nature. Hence leached barite is usually preferred for this; the BIS standardized the specification (IS: 1683 1973). In this, water solubility, moisture content, manganese, copper and iron are objectionable, while color, size, density and pH values also play important roles. The specification of bleached barite is as follows:

i

Color

Close match to the approved sample.

ii

Sieve residue:
(a) Through 75 micron IS Sieve
(b) Through 150 micron IS Sieve

0.4% max.
0.01% max.

iii

Relative density 27o C

4.2 to 4.5

iv

pH

6 to 8

v

Moisture content

0.5%

vi

Matter soluble in water

0.5% max.

vii

Mn

0.005% satisfies requirement of test

viii

Cu

to satisfy requirement of test

ix

Fe

to satisfy requirement of test

For other industries such as explosive, glass, leather textile, paper, etc., there is no BIS specification at present and the concerned industries have their own criteria of acceptability.

During the preparation and updating of the inventory of barite as on 01.01.1985, it was found of the exploration agencies by and large lay emphasis on three parameters, namely, BaSO4, specific gravity and color which apparently are easier for them to determined and report. In a large number of cases, however, one or the other of these parameters was not reported by the exploration agencies for the purpose of preparation of inventory. Keeping in view the limitations of the reported data, the following basis was adopted for the purpose of classifying the reserves.

i

Chemical A

BaSO4: +97% either off color or information on color not available

ii

Chemical B

BaSO4: +90% specific gravity either less than 4.75 or information not available.

iii

Oil well drilling

BaSO4: +90% specific gravity 4.15 (min.)

iv

Paint

BaSO4: +95% Color snow white to white.

v

Low-grade

BaSO4: < 90%

The exploration agencies can give board end use classification of reserves according to BaSO4 content, Sp. Gravity and color of the mineral, and recommended of the following classification keeping in view the limitation of the exploration agencies.

i

Chemical A

BaSO4: 97%, SiO2: 2%, Fe: 0.1% Color: off color

ii

Chemical B

BaSO4: +90% specific gravity: less than 4.15 (min.)

iii

Oil well drilling

BaSO4: 90%, SiO2 + Al2O3 = 6%, CaCO3 = 2%, Fe: 1.5%

iv

Paint    

BaSO4: +95% Color snow white to white.

v

Low-grade

BaSO4: < 90%


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