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The grain-size compositions of finely milled powdered refractories, raw materials, and suspensions are determined as a rule by the method of sedimentation analysis with periodic sampling [i]. These methods do not require complicated apparatus, but they are very laborious and yield results only after 12-24 h from the start of the test. The completion of sedimentation analysis by collecting and continuously weighing residues makes it possible to automate the measurement process, to cut the time to 1-6 h, and to increase the volume of information obtained about the graln-size composition of the sample.The All-Union Institute of Refractories has developed and implemented a sedimentation method for powders and suspensions using the VSA-500 mg automatic sedimentation balance manNfactured hy the "Gosmetr" factory. This balance, which has a maximum loading of 500 mg, is an automatic device designed for continuous weighing and recording of masses of suspension particles deposited on a pan. The design of the apparatus consists of two blocks --the scales themselves, and the control and recording panel.The working principle of the halance ks based on the compensation of the weight imbalance hy the power action of an electric circuit of the automatic equilibrium type. The scheme is shown in Fig. i. In addition to the beam i, the suspension 2 with the stirrup 3 and the insulator 4, necessary to provide rigid fixing of the beam during placement and removal of the suspension, the scales have a built-in gyro mechanism 5 (50, i00, 200, and 500 mg) for checking the metrological characteristics and matching parameters of the circuit, and also a gyro for approximate balancing of the beam during immersion of the suspension in the liquid. Furthermore, the beam is fitted with a differential inductive sensor 6 controlling the displacement, and a magnetoelectric compensator 7.All-Union Institute of Refractories. "Gosmetr" Factory.

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The process of sulfidation of C 12 C 14 -olefin fractions in the presence of various dialkyl dithiophosphoric acid derivatives is studied. The optimal catalyst concentrations and process duration that help get a high-sulfur product containing 24.8 wt. % of chemically bound sulfur are determined.The product can be recommended as an additive for improving tribological properties of lubricants.