Cabot announced a cost-reduction program designed to boost earnings, and said it has cut 250 jobs from a total work force of 4,500.

Cabot Corp., Boston, the world’s biggest producer of carbon black, announced a cost-reduction program designed to boost earnings, and said it has cut 250 jobs from a total work force of 4,500. The company also said it plans to make an initial public offering of about 15% of its microelectronic materials business and separate its liquefied natural gas unit from the rest of its operations.