​      Quality and quality management system offer a set of operations that unite all phases of the production process - product policy, planning, marketing, sales, personnel, innovation and technology - so that the enterprise can successfully operate in the market. Quality is:
       a. the key aspect for making a purchase for the most important customers. Losing an order because of insufficient quality                is much worse than because of an excessively high price: you can lose the customer forever; 

       b. leads to strengthening the company's position in the market. In open markets, products become increasingly                                    interchangeable. The level of quality becomes decisive;
        c. the main tool for reducing costs. It is always cheaper to produce correctly and the first time than to correct a mistake                    later;
       The implementation of a product quality management system is the most important criterion for the production of high-quality pellets.
     Pelletizing plants are complex production facilities that include a raw material receiving and warehousing department (limestone, bentonite, coal), additive crushing and grinding departments, iron ore concentrate receiving systems from the beneficiation plant or warehouses, batch mixing departments, pelletizing, roasting, screening, warehousing and shipping finished pellets, a process fan department and an exhaust gas cleaning section. Each section has its own process cycle that contains process indicators whose values affect the quality indicators of the final product. The standard quality management system regulates the main quality indicators of commercial pellets (e.g. compressive strength, impact strength, abrasion resistance, grain size distribution, fines content and chemical composition). It is believed that the fulfillment of these indicators confirms the quality component of the produced and shipped pellets. However, product inspection at the end of the process is too late and expensive an approach. The correct ideology is to move from detecting defects in manufactured products to reducing or eliminating them during the life cycle of the manufacturing process of these products. A preventive approach to quality issues is achieved by analyzing the technological process, monitoring and improving it. A technological process is defined as a set of conditions or a set of causes working together to obtain a given result. Typically, it is a mixture of machines, methods, materials and people. Measurements are used to monitor technological processes and take measures to minimize the possibility of producing defective products or providing inadequate services to the customer.
      The main factors causing violations of production technology are:
      a. use of raw material, materials and semi-finished products that do not meet the requirements of the enterprise's                                regulatory and technical documentation and the requirements of international standards;
      b. operation of equipment with deviations from design requirements, technology requirements, technical documentation               and established key parameters of technology and equipment;
       c. work on faulty equipment and use of faulty tools;
      d. absence of process control and management devices provided for by the technology, as well as faulty ones or those that                 have not been verified within the time established by the regulations;
       e. violation of the frequency of recording the established key parameters of technology and equipment;
    The ideology of the quality system includes preventive management of processes at all stages of production. That is, the products must be obtained not only with the appropriate quality characteristics, but also without deviations from the established parameters of technology and equipment at all stages of pellet production. In essence, technology is a set of factors (indicators), the correct observance of which will allow obtaining the required final result. At the same time, some indicators affect the stability of the process more than others. Such parameters are defined as key parameters of technology and equipment.
      The following structural approaches are implemented in the modern quality management system for produced pellets:
       a. the concept of key parameters of technology and equipment (KPT&E) is introduced;
       b. the concept of products accepted from the first presentation is introduced;
    Fulfillment of key parameters of technology and equipment allows conducting the technological process within certain limits that do not allow at each stage of the process to produce a negative impact on the quality of the final product.
      The parameters of the KPT&E are formed on the basis of the following approach:
       a. the key parameter that directly affects the final result is determined based on the current regulatory documentation                       governing this parameter;
       b. the acceptance criteria for each key parameter are determined;
       c. the method and frequency of monitoring the key parameter are determined;
      d. the form of recording the key parameter and the person responsible for monitoring the values of each indicator are                       determined;
       e. the actions of the personnel in the event of a deviation of the key parameter from the required established values are                     determined;
      Pellet production is associated with many factors that affect the technological process. These are factors related to the nature and properties of the materials themselves, the method and conditions of their preparation, and factors directly related to the operation of the main technological equipment and the roasting machine itself. Therefore, the values of the key parameters of the technological process are also characterized by certain deviations. Each type of deviation is assigned a specific position and marker color. Each marker color corresponds to a green, yellow and red zone:
       a. in which there is no violation of the technology and the process is carried out in accordance with the deviation limits                    established by the regulatory documentation - no action is taken (green marker);
       b. in which the technological process is in the instability zone - it is necessary to take measures to stabilize the parameters,                otherwise there is a certain probability of releasing low-quality products (yellow marker);
       c. in which there is a fundamental violation of the technological process or a critical equipment failure, leading with a high             degree of probability to the release of products that do not meet the established requirements for one or more                                 parameters - it is necessary to immediately take measures to stabilize the parameters to the values established by the                         regulatory documentation or, if it is impossible to promptly respond to stabilize the parameter, stop the process to                        eliminate the causes that caused this discrepancy (red marker);
       Since the process instability zone (yellow zone) is a buffer zone and is located between the comfort zone (green zone) and the discomfort zone (red zone), in practice it is customary to select it from the boundary values of the green zone deviations. The deviation range of the yellow zone must be sufficient both in terms of the value and the time interval for timely response by personnel. In some processes, only the green and red zone deviation gradation is used. This practice is mainly used when reflecting the operation of equipment - (e.g. works/does not work, complies/does not comply). The boundaries of the zones should not intersect and be without breaks (gaps) when determining the boundaries. The list of KPT&E and the parameters of the deviation boundaries are periodically supplemented and adjusted depending on the analysis of the work for the reporting period (e.g. quarter), when changing the requirements of the technological process. using new technologies, materials and equipment. An example of the key parameters of the KPT&E and deviations by zones is given in figure. Each enterprise producing pellets, depending on the requirements of the technology and the equipment used, independently determines and establishes a list of the necessary key parameters of the technology and equipment sufficient to control the technological processes and equipment. Different enterprises have different technical bases (automation of production, availability of control devices) and availability of personnel. Some of the KPT&E parameters are determined by automation systems online (for example, temperature, pressure, vacuum, layer height, etc.), other parameters require direct human participation for periodic manual sampling and obtaining the result (compressive strength, abrasion resistance, etc.). The higher the degree of automation of the key parameters, the more stable the control system is, excluding the influence of the human factor. In an ideal solution, with the correct selection of key parameters describing the technological process and their full automation, there is practically no need for a significant number of quality control personnel at the enterprise. That is, if our process is carried out in the zones of green and yellow markers, we can be sure that we will receive pellets of the specified quality at the output without additional product control methods.
     The concept of products accepted on first presentation is directly related to the key parameters of the KPT&E. The term characterizes the production of pellets in compliance with the requirements established by the KPT&E and was introduced to assess the quality of manufactured products throughout the entire process. Pellets are considered to be of excellent quality if they are produced without violating the parameters of the KPT&E, i.e. the first presentation is considered equal to 100%. The formula for calculating the level of products accepted on first presentation for pellet plants is given below:

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Presented – quantity of products presented for certification, t;
KPT&E   – quantity of products manufactured in violation (red marker) of KPT&E parameters, t;
      The level of products accepted at the first presentation is an important factor in assessing and motivating the shop staff to produce high-quality products and is a target factor influencing the remuneration of shop staff, from line personnel to the head of the enterprise.
     The next important step of the quality management system after identifying deviations of key parameters of technology and equipment is to identify the root causes that caused these violations, conduct analyses for each violation and develop technical and organizational measures to reduce or prevent their recurrence. All deviations of the KPT&E are divided by types of violations. Analysis of violations is carried out with all deviations that fall into the red zone. Analysis is carried out by technical specialists of the enterprise with the participation of the personnel who committed this violation. The activities developed based on the results of the analyses must contain specific deadlines for implementation, the final result of implementation and clear methods of monitoring and recording the results. 

       All analyses of violations with proposed measures to prevent them are systematized and form a single knowledge base that allows for training of current and new personnel of the enterprise and continuous improvement of the technological process. 

     Continuous monitoring of the functioning of the pellet production quality system is carried out through technological inspections and audits. 

    As a result of technological inspections, cases of violation of regulatory documentation requirements, deviations of parameters from established values are identified, bottlenecks of the technological process are determined and measures are developed to eliminate them and improve the technological process. The optimal frequency of technological inspections is once a week. Technological inspections should cover all sections of the workshop. Particular emphasis should be placed on areas where systematic deviations in the parameters of the KPT&E and violations of the technological process are periodically identified. The result of the technological inspection is a technological protocol reflecting violations, methods and terms of their elimination, as well as recommendations for improving the technological process.

     The audit system covers the entire range of functioning of the quality system and is carried out to confirm the current quality system at the enterprise to the requirements of ISO 9001. The system's performance is assessed according to the "Quality management process assessment matrix", which includes the following sections:
        a. working with KPT&E;
        b. debriefings;
        c. analysis of the effectiveness of the developed activities;
        d. audits and walk-throughs;
        e. knowledge base;
        f. achieving goals;
        g. working with key clients;
        h. working with complaints;
Each section of the matrix is assessed on a 5-point scale. 

    For the functioning of the quality system with the reflection of the cause-and-effect relationship of the occurrence of deviations in the technological process, a quality guide is formed. The main provisions of this document are:
        a. the basis for analyzing the causes of quality incidents;
        b. a reference book of all current regulatory and technological documentation for the enterprise;
        c. the basis for training technological personnel;

​       d. involving enterprise personnel in the functioning of the quality system;
       The structure of the guide consists of two parts – a static part and a dynamic part, which includes the following sections:
        Static section:
        a. general characteristics of the workshop;
        b. production flow chart;
        c. production apparatus chain chart;
        d. list of main process equipment for which quality control and monitoring parameters have been established;
        e. chart of location of quality control and monitoring points;
        f. current list of quality control and monitoring parameters indicating criteria for each indicator and personnel actions in                case of deviations;
        g. current references to all regulatory documents governing the quality management process;
       Dynamic section:
       a. ABC analysis of the reasons for the release of non-conforming products. deviations of the KPT&E (for a month,                           quarte, year) by type, shift;
       b. dynamics of the enterprise indicators set as targets with the allocation of the share of achieved goals;
    The guide is subject to monthly updating with the dynamic and static parts. If the dynamics of one or more indicators deteriorate from the previous month, new corrective measures must be developed. 

      The knowledge base is a global system document structuring all elements of quality management and freely available at the enterprise for the personnel involved in the technological process. It includes current versions of the KPT&E, regulatory documents, quality guides, materials on quality incident analysis and measures to eliminate them, statistics on violations and first presentation and serves as a basis for personnel training and the functioning of the quality management system at the enterprise. It is in electronic form and is updated monthly. The stages of implementing the quality management system at the enterprise are given in figure.