Abstract: A positive electrode mixture layer for a lithium-ion secondary battery suitable for producing a lithium-ion secondary battery with high rate characteristics at an ordinary temperature and low temperatures and low internal resistance (DCR) at low temperatures, characterized by including a positive electrode active material, a binder, and a conductive additive, in which the conductive additive includes carbon black, a carbon nanotube (1) having an average fiber diameter of 80 to 400 nm, and a carbon nanotube (2) having an average fiber diameter of 0.4 to 3.0 nm, the content rates of the carbon black, the carbon nanotube (1), and the carbon nanotube (2) in the conductive additive are 40 to 80% by mass, 10 to 50% by mass, and 1 to 30% by mass, respectively, and the content rate of the conductive additive in the positive electrode mixed layer is 0.1 to 5.0% by mass.

Abstract: A spark plug for an internal combustion engine is disclosed. A semiconductor material having a resistance of 5.times.10.sup.2 -5.times.10.sup.4 M.OMEGA./mm is coated or baked in the form of a band on the peripheral surface of a basal part of a leg portion of an insulator of the spark plug. Preferably, at least the basal part of the leg portion, including the band, is covered with a water-repellant insulating coating. An inner wall of a metal shell of the spark plug is desirably coated with a water-repellant material at an area facing at least the peripheral surface of the basal part of the leg portion of the insulator.

Abstract: The present invention relates to a process for the treatment of a slag generated in an ironworks and comprises rough crushing a solidified slag generated in an ironworks with a crusher into a specified particle size, a step of further crushing for separation, and dividing the crushed slag by specific gravity separation with a dry vibrating air classifier and a step of magnetic separation into a metal component and a slag component. This process can be carried out even in a cold district where water freezes in winter.

Abstract: A method of modifying dust and sludge simultaneously with steel slag produced in a steel making process. In a reactor equipped with a heating electrode, a predetermined amount of a hydrous silicate mineral as a modifier is fed to molten steel slag having a high temperature to decompose the hydrous silicate mineral, causing the molten steel slag to the stirred with a gas produced as the result of the decomposition and the slag modifying reaction to be promoted, whereby the dust, sludge and steel slag produced in a steel making process not only can be made harmless but also can be effectively reused.

Abstract: The present invention relates to a process for the simultaneous treatment of dust, sludge and steel slag generated in the steel-manufacturing step, characterized by using a specified amount of a silicate mineral containing water of crystallization as a modifier. This process comprises adding a silicate mineral containing water of crystallizaiton to molten steel slag having a high temperature to carry out the modification of the slag, while stirring the slag by the gas generated by the decomposition of the silicate mineral containing water of crystallization, According to the process, dust, sludge and steel slag can be treated simultaneously to give an innoxious material which can be utilized satisfactorily.