SU88615A1 - Method for producing calcium boride and free boron - Google Patents

Description

The thermal decomposition of natural calcium borates into calcium oxide and boric anhydride is known. It is also known to reduce the oxygenation of boron compounds by carbon and calcium carbide to free boron or boron carbide. The preparation of calcium boride by calcining a mixture of oxygen compounds of boron, carbon, and any calcium salts that decompose when heated is also known.

A method is proposed for producing calcium boride and free boron from natural calcium borates using carbon and calcium carbide as reducing agents, which combines all of the above techniques into a single process for producing calcium boride and boron from natural borates.

The peculiarity of the method is that a mixture of equal weight quantities of carbon and calcium borate is calcined at temperatures from 100 to 600 ° C, and then the resulting mass is calcined with calcium carbide at a temperature of about 1600-1700 ° C. including calcium borate and 1 wt. including carbon enter weight. including calcium carbide.

Example s.

The composition of the initial mixture:

1) Boratovo ore - colemanite - 2СаОВ2Оз5Н20.

Chemical composition: BgOs-50.9% CaO-27.1%. NZO-20,4%

2) Calcium carbide - CsSg. Chemical composition: CAC2-79%

CaO - 17% С - 1%

3) Soot and charcoal

Charcoal

Chemical composition: С-85-90%

NgO-10-5%

Oa-3-4%

ash - 2-1%

C-98.99%

Soot. ash - 2 -1%

A mixture of equal weight quantities of boron ore and soot with charcoal is subjected to crushing, grinding and briquetting, followed by roasting for 6 hours in tube furnaces at a temperature of from 100 to 600 °. The resulting mass is then mixed with calcium carbide, which is added in amounts.

Calcium carbon: carbon: carbide calcium: 1: 1: 1, corresponding to the weight ratio of calcium borate, and calcining the mixture at a temperature of about 1600-1700 °.

Procuring is performed on laboratory single-phase, 4–0 kilt single-phase laboratory furnaces with 2 single-phase single-phase transformers of 20 ket each with a 5-step regulation, combined with Scott's circuit.

Pécs) lined with do.aomite brick with a fire resistance of 1920 °. A mixture is added to the lining with the addition of 10–15% potassium carbide, which raises the melting point to 2000 °. The same mixture is used as thermal insulation, which protects the charged chemicals during the course of the reaction from the nitrogen of the air.

The process is 16 hours. The temperature in the furnace on the reaction mass was measured with a pyrometer and was 600 ° through the first 2 hours, after 8 hours after 16 hours - 1650 °, after 10 hours from the start of the process for four hours the temperature was maintained from 1650 to 1700 °; the last 2 hours the temperature was maintained in the range of 1700-1750 °.

Apalysis 11 °, of the studied calcium boride and boron showed that the percentage of boron in calcium boride is 18-22%, the percentage of calcium — over 70%. The yield of calcium bond is 25–26%, which is 60–65% of the theoretical value.

The yield of free boron is between 8 and 10%, and between 45 and 48% of the theoretical.

PRED MET & A REFERENCE

Claims (2)

1. A method of producing calcium boride and free boron from natural calcium borates, using carbon and calcium carbide as reducing agents, from .I and h with 5G in that it was a mixture of equal weight carbon and calcium borate. subjected to roasting at temperatures from 100 to 600 °, followed by calcining the resulting mass with a carbide cut at a temperature of about 1600-1700 °. 2. Acceptance of the method according to claim 1, characterized in that. that calcium carbide is introduced in amounts equivalent to the weight ratio — calcium borate: carbon: calcium carbide -1: 1: 1.