GOST 25699.6-90 PDF

Full title and description

GOST 25699.6-90 — Углерод технический для производства резины. Методы определения рН водной суспензии (English: Carbon black for rubber industry — Methods for determination of pH value). The standard specifies laboratory procedures for preparing an aqueous suspension of technical carbon (carbon black) and measuring the pH of that suspension by specified methods.

Abstract

This standard defines two test procedures (Method A — an express method, and Method B — a reference method) for determining the pH of an aqueous suspension of technical carbon used in the rubber industry. Method A is not intended for channel (channel-type) carbon. The document covers sample mass, suspension preparation, mixing and timing, measurement technique (pH-meter/ion-meter), and reporting of results.

General information

• Status: Active / in force (restriction on validity was removed by protocol).
• Publication date: Approved July 27, 1990; effective from July 1, 1991.
• Publisher: Adopted by the State Committee for Standards of the USSR (Gosstandart) / Interstate (Mezhgosudarstvennyy) standard; developed by the Ministry of Chemical and Oil Refining Industry of the USSR.
• ICS / categories: Rubber and plastics; raw materials for rubber industry — classification listed as 83.040.20 (OKS/sectoral classifier).
• Edition / version: Designation year 1990 (GOST 25699.6-90) — replaces GOST 25699.6-83; original text effective 1991.
• Number of pages: 4 (concise test method standard).

Scope

The standard applies to technical carbon (carbon black) intended for the manufacture of rubber goods and specifies laboratory methods for determining the pH of an aqueous suspension of that carbon. It is intended for use in quality control, acceptance testing and routine laboratory checks of carbon black batches. The document describes sample masses, suspension volumes, mixing times and conditions, allowed measuring instrumentation (pH-meter or ion-meter), and handling of layered suspensions during measurement. Method A is an express procedure and explicitly excludes channel (channel-type) carbon.

Key topics and requirements

• Preparation of test suspension: specified sample masses for granulated and non‑granulated carbon, use of distilled water and wetting with alcohol before dilution.
• Mixing and homogenization: mixer/agitator specifications, immersion depth of blades, mixing time (e.g., ~30 s) and sample transfer procedures.
• Measurement: use of calibrated pH‑meters or ion‑meters; procedure for measuring pH immediately after preparation or under controlled stirring if suspension separates.
• Two alternative methods: Method A (express) and Method B (reference); limitations of Method A (not for channel carbon).
• Reporting: how to record pH results, sample identification and conditions of measurement.

Typical use and users

Intended users are quality control laboratories at carbon black manufacturers, rubber compounders (tire and general rubber goods producers), material testing laboratories, standardization bodies and researchers working with carbon black. Typical use cases include incoming inspection of raw carbon black, in‑process quality checks, supplier qualification and batch acceptance testing.

Related standards

GOST 25699.6-90 is one part of a multipart national series on technical carbon for the rubber industry. Closely related documents include other parts of the GOST 25699 series (e.g., 25699.1–25699.16), the product specification standard GOST 7885-86 (Carbon black for rubber industry — Specifications), and referenced general test standards listed within (instrumentation and laboratory practice standards). Where applicable, historical alignment with relevant CMEA / interstate standards is indicated in the document metadata.

Keywords

GOST 25699.6-90; carbon black; technical carbon; carbon black pH; aqueous suspension; rubber industry; pH determination; test methods; quality control; pH‑meter.

FAQ

Q: What is this standard?

A: GOST 25699.6-90 is a national (interstate) standard that specifies laboratory methods for determining the pH of an aqueous suspension of technical carbon (carbon black) used in rubber manufacture.

Q: What does it cover?

A: It covers two measurement procedures (an express Method A and a reference Method B), sample preparation (sample mass, wetting, dilution), mixing/homogenization, measurement technique (pH‑meter/ion‑meter) and reporting of results. Method A is not applicable to channel-type carbon.

Q: Who typically uses it?

A: Quality control and analytical laboratories at carbon black producers, rubber compounders (tires and technical rubber goods), independent testing labs, and standards organizations use this standard for batch acceptance and routine checks.

Q: Is it current or superseded?

A: The 1990 edition (GOST 25699.6-90) replaced an earlier 1983 version (GOST 25699.6-83). Public sources list the 1990 text as in force with removal of prior expiration restrictions; users should verify national-adopted status for their country or any later amendments before relying on it for certification.

Q: Is it part of a series?

A: Yes — it is one part of the GOST 25699 series covering technical carbon for the rubber industry; related parts address other test methods, physicochemical properties and specification items. It is also referenced by broader product specification standards such as GOST 7885-86.

Q: What are the key keywords?

A: Carbon black; technical carbon; pH of aqueous suspension; test method; rubber industry; GOST 25699 series; quality control.