JPS588565B2 - Manufacturing method of magnetic fluid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a magnetic fluid, particularly a method for producing a magnetic fluid using waste fluid from wrapping during the production of steel balls for rolling bearings.

Colloidal solutions as magnetic fluids were invented in 1965 by Papel, an American, and subsequently applied research and application development was carried out at NASA, and now water-based products and various oil-based products are commercially available. There is.

In addition, as a manufacturing method, methods such as a wet pulverization method, an adsorption-organic phase dispersion method in an aqueous solution, and a dissolution method are known.

Applications include sealing materials, lubricants, etc. that utilize magnetic fields.

By the way, this conventional commercially available product is expensive, costing several tens of thousands or hundreds of thousands of yen per liter, which has limited its widespread use.

This invention solves the above-mentioned conventional problems and develops a method of obtaining a magnetic fluid of a predetermined concentration at an extremely low cost.The structure of this invention will be explained below.

The waste fluid generated during the manufacturing process of high-precision steel balls used in rolling bearings, especially the wrapping process, exhibits strong magnetism.

That is, the main components of this waste liquid include fine iron powder such as bearing steel, chromium dioxide, light oil, oleic acid, etc., and are a sludge-like liquid.

The iron powder in this sludge-like liquid is fine primary particles or
Iron particles are contained in the form of secondary particles, which are a collection of secondary particles, and even higher-order particles such as tertiary particles, which appear to be iron particles of various sizes.

By the way, this strongly magnetic waste liquid cannot exist stably in the liquid phase if it is simply filtered or centrifuged (
The proportion of fine iron particles (dispersed) is small, so the supernatant after separation does not exhibit much magnetism.

However, when this waste liquid is heated as it is or when a similar oil is added in place of the base oil, fine iron powder that can be stably dispersed increases in the liquid phase, and therefore floats and disperses in the supernatant liquid. It was found that the coarse iron powder and impurities other than the fine iron powder were colloidized and precipitated at the bottom, and that the remaining liquid containing the fine iron powder, that is, the supernatant liquid, exhibited strong magnetism.

This invention utilizes this property, and the specific manufacturing method thereof will be explained as follows.

Specific manufacturing method 1: The waste liquid from the wrapping process of steel balls for rolling bearings is heated as it is to around 240°C (the boiling point of light oil).

At this time, the proportion of primary particles of iron powder colloidally dispersed in the base oil increases linearly as the heating temperature increases.

Next, the heated liquid is cooled to near room temperature, and the cooled liquid is filtered or centrifuged to remove coarse iron powder and impurities other than colloidal iron powder, thereby producing a colloidal solution of fine iron powder, i.e. Obtain ferrofluid.

Specific manufacturing method 2: The maximum heating temperature can be lowered by diluting the waste liquid from the wrapping process of steel balls for rolling bearings by adding oil similar to light oil, which is a base oil such as kerosene.

That is, this liquid is heated to around 180°C (the boiling point of kerosene).

Next, this liquid is cooled to room temperature or near room temperature, and the cooled liquid is filtered or centrifuged to remove coarse iron powder and impurities other than the colloidal iron powder. Similarly, a colloidal solution of fine iron powder, that is, a magnetic fluid is obtained.

The liquids obtained by the above specific production methods 1 and 2 exhibit relatively strong magnetism as they are, but if they are further concentrated and refined to a predetermined concentration, they can be made into concentrated or diluted colloidal solutions of the desired concentration. Can be done.

As methods for the concentration treatment, there are a method of vaporizing the base oil and a method of adding a polar solvent for coagulation such as acetone.

As explained above, this invention heats the waste liquid generated during the wrapping process of steel products as it is or a solution in which an oil similar to the base oil in the waste liquid is added instead of the base oil to a predetermined temperature, Colloidalized and precipitated and dispersed in base oil 1
The proportion of iron powder in the secondary particles is increased, and the liquid in which the iron powder turns into a colloid after heating and is precipitated and dispersed is allowed to cool down to room temperature or near room temperature. Compared to conventional commercially available magnetic fluids, it removes coarse iron powder and impurities other than the liquid in which the powder is colloidized and dispersed, and the resulting colloidal solution is either left as is or concentrated to a predetermined concentration. , the desired magnetic fluid can be produced easily and at a very low cost.

In addition, since the raw material is waste liquid from wrapping steel products, it is extremely advantageous in terms of resource conservation and waste utilization.

Claims (1)

[Claims] 1 A solution in which an oil similar to the base oil in the waste liquid is added to the waste liquid generated during the wrapping process of steel balls is heated to a predetermined temperature, and the solution is colloidized and precipitated and dispersed in the base oil 1 The proportion of iron powder in the secondary particles is increased, and after heating, the iron powder turns into a colloid and precipitates and disperses. The liquid is cooled to near room temperature, and the cooled liquid is passed through a filter or centrifuge to turn the iron powder into a colloid. A method for producing a magnetic fluid, characterized by removing coarse iron powder and impurities other than the liquid to be dispersed. 2 A solution in which an oil similar to the base oil in the waste liquid is added to the waste liquid generated during the wrapping process of steel balls is heated to a predetermined temperature, and primary particles of iron powder are colloidized and precipitated and dispersed in the base oil. After heating, the liquid in which the iron powder is colloidized and precipitated and dispersed is cooled to near room temperature, and the cooled liquid is filtered or centrifuged to remove any liquid other than the liquid in which the iron powder is colloidized and dispersed. Removes coarse iron powder and impurities,
A method for producing a magnetic fluid, further comprising concentrating it to a predetermined concentration.