天蚕土豆,辰东

Chemical knowledge

The Application and Technical Specification of Barite

2016/01/05 Bmschem

Barite, a kind of Ba-bearing sulfate mineral, is the most important industrial raw mineral material for barium and barium compounds production. As early as 1920s, barite was used as weighting agent for oil and gas drilling fluids because of its high specific gravity, high hardness, stable chemical properties and insolubility in water and acid. At present, America barite consumption in this field accounts for about 90% of the whole barite consumption. Our country has rich barite resources, world’s largest reserves and outputs. Besides, we are the world’s biggest exporter of barite and occupy an important place in the world market.

Now, the biggest industrial use of barite is as weighting agent for oil and gas drilling mud. The mud with this weighting agent can cool the drill bit, reinforce borehole walls and control the pressure of crude oil and natural gas, thus stabilizing oil and gas production and preventing blowout accident. Statistical data shows that about 85% of global barites are used as weighting agent at present.

The second largest application of barite is making various kinds of barium products, for example barium carbonate, barium chloride, barium titanate, barium sulfate, barium nitrate, barium oxide and so on.

Barium carnonate (BaCO₃): the largest application is used in other barium salts production and glass industry. Barium carbonate is added to TV tube and electronic computer display to absorb X-ray. Putting some barium carbonate in ceramic can make texture uniform and improve the abrasive resistance and rotproofness. Barium carbonate is also used to remove sulfate radical in sodium tripolyphosphate production.

Barium chloride (BaCl₂): it is used in pigment, coating, tanning, insecticide, pharmacy, pringting ink, water softener, heat treatment of metal, brine purification in chlor-alkali industry, etc.

Barium titanate (BaTiO₃): it is a major raw material of electronic ceramics, foundamental strong dielectric material and the core of integrated ceramic capacitor.

Barium sulfate (BaSO₄): precipitated barium sulphate is used as white pigment, filler and colorant of rubber, barium meal in medicine, the coating of photographic paper and so on.

Barium nitrate (Ba (NO₃)₂): it is mainly used in signal detonator, exploder, detonator, ceramic glaze, medicine, etc.

Barium oxide (BaO): it is mainly used in surface hardening and heat treatment groove, artificial leather, magnesium refining and the extention of metallurgical furnaces’ service life.

Charlton white (lithopone): it is white non-poisonous pigment with high covering power. Lithopone, made of 70% barium sulfate and 30% zinc sulfide, is widely used in paint industry.

Besides, barite is also used in extracting barium, getter of vacuum tube, forming alloy with other metals, bearing production.

Each industrial sector has different index requirement of barite ore because of its different uses.

(1) Oil Drilling Grade Barite

Specific gravity: not less than 4.2

Fineness: according to wet sieve analysis, not less than 97% of barite pass 200 mesh sieve, 85% to 95% pass 325 mesh sieve (gravimetric method).

Viscosity effect: if add 1% of gypsum liquild into barite powder water suspension whose specific gravity is 2.5, the apparent viscosity of the suspension shall not exceed 125 cPa•s.

The content of soluble matter: not more than 0.1% (weight ratio).

(2) Chemical Grade Barite

Specifications of barite used in chemical industry (see table 1)

Grade Classification of Barite Used in Chemical Industry
Grade	BaSO₄(%)	SiO? (%)	Fe₂O₃(%)	Al₂O₃(%)	Water-soluble Salt (%)
Ⅰ	95	＜1.5	＜0.5	＜1.0	＜0.3
Ⅱ	90	＜2.5	＜1.5	＜2.0	＜1.0
Ⅲ	85	＜2.5	＜1.5	＜2.0	＜1.0

Barite used in oil paint is required high whiteness. To manufacture barium salts, barite need contain 90% to 95% of BaSO₄. Some departments require the cracking temperature of heated barite is bewteen 700 to 800℃.

(3) Filler Grade Barite

The quality requirements for barite used as filler in rubber and papermaking(see table 2)

Grade Classification of Barite for Filler in Rubber and Papermaking
Grade	Moisture (%)	BaSO₄(%)	SiO? (%)	Water-soluble Salt (%)	Specific Gravity (%)
Ⅰ	0.3	97	＜0.5	＜0.3	4.3-4.6
Ⅱ	0.5	95	＜0.5	＜0.3	4.3-4.6